Source: UNIV OF MINNESOTA submitted to
METHODS FOR ACHIEVING OPTIMAL PROTEIN UTILIZATION IN RUMINANTS
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
REVISED
Funding Source
Reporting Frequency
Annual
Accession No.
0086506
Grant No.
(N/A)
Project No.
MIN-16-048
Proposal No.
(N/A)
Multistate No.
(N/A)
Program Code
(N/A)
Project Start Date
Oct 1, 2009
Project End Date
Sep 30, 2014
Grant Year
(N/A)
Project Director
Stern, M. D.
Recipient Organization
UNIV OF MINNESOTA
(N/A)
ST PAUL,MN 55108
Performing Department
Animal Science
Non Technical Summary
The US dairy and beef cattle industries are major contributors to diets of Americans, supplying substantial quantities of protein, energy and calcium to the diet. Because protein is the most expensive nutrient supplied in the ruminant diet, it is especially important to maximize the efficiency of protein utilization for production of animal products. One of the goals of any profitable enterprise should be to maximize profit margins by increasing the conversion efficiency of dietary nutrients (energy and amino acids) into animal protein using means that are acceptable to consumers. Protein represents a major fraction of ruminant rations and therefore optimizing its utilization should have important economical consequences. Ruminant animals use dietary crude protein less efficiently than monogastrics due in part, to alteration of the protein by microbes that are found in the rumen, the first compartment of the four compartmental stomach of ruminants. Nutritional models for feeding protein to ruminants have evolved from basic to more complex systems that accounts for the changes to protein that occurs in the rumen. Ruminal degradation of protein (proteolysis) from dietary feed ingredients is one of the most important factors influencing intestinal amino acid supply to ruminants. Proteolysis determines the availability of ammonia-nitrogen, amino acids and other dietary components that influence microbial growth rates in the rumen. Rate and extent of ruminal proteolysis affects not only microbial protein synthesis but also determines the quantity and quality of undegraded dietary protein that will reach the duodenum. As a result, availability of amino acids in the small intestine is a function of the amount of feed protein that passes undegraded through the rumen and the amount of microbial protein synthesized in the rumen. Because microbial protein has a better amino acid profile than most feed proteins, this remains an important area of study. One of our major goals is to maximize microbial protein synthesis in the rumen. The more complex ruminant feeding models consider protein digestion in the small intestine with the understanding that all dietary protein sources are not digested to the same extent. With improved techniques that alleviate use of surgically prepared animals, such as the three-step in situ/in vitro procedure that we developed at the University of Minnesota, the NRC (2001) assigned estimates of intestinal digestion to the ruminally undegraded proetin fraction of each feedstuff. However, there is still a void in the intestinal digestion of these types of estimates with certain feedstuffs that needs to be rectified. As new protein sources are incorporated into ruminant diets, we plan to evaluate the ruminal undegradable protein fraction and intestinal protein digestion. These values will help producers make educated economical decisions on use of protein in the diets that they formulate. Compilation of all the protein sources that we have evaluated for ruminal protein degradation and intestinal protein digestion in the past 13 years will make a significant contribution to the nutritional models for feeding protein to ruminants.
Animal Health Component
20%
Research Effort Categories
Basic
80%
Applied
20%
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
3023499101075%
3023399101025%
Goals / Objectives
The US dairy and beef cattle industries are major contributors to the diets of Americans, supplying substantial quantities of protein, energy and calcium to the diet. Because protein is the most expensive nutrient supplied in the ruminant diet, it is especially important to maximize the efficiency of protein utilization for production of animal products. One of the goals of any profitable enterprise should be to maximize profit margins by increasing the conversion efficiency of dietary nutrients (energy and amino acids) into animal protein using means that are acceptable to consumers. Ruminant animals use dietary crude protein less efficiently than monogastrics due in part, to ruminal nitrogen metabolism. In ruminants, dietary protein is divided into rumen degradable (RDP) and undegradable protein (RUP) with RDP composed of non-protein and true-protein N. True protein is degraded to peptides and AA, and eventually deaminated into ammonia-N or incorporated into microbial protein. Rumen output consists of ammonia-N, undegraded protein (dietary or endogenous), and microbial protein. When dietary RDP is in excess of the amount required by ruminal microorganisms, protein is degraded to ammonia-N, which is absorbed from the rumen and then metabolized to urea in the liver, and lost in the urine. Therefore, it is important to maximize microbial protein synthesis in the rumen and reduce wastage of nitrogen as ammonia. The real crude protein needs of ruminants are amino acids, and thus feeding rations that meet the amino acid requirements of ruminant animals should reduce wastage of dietary protein and increase the efficiency of utilization of protein for animal production (milk and meat). Nutritional models for feeding protein to ruminants have evolved from basic crude protein to more complex systems based on RDP, RUP and intestinal digestion of RUP. The NRC (2001) assigned estimates of intestinal digestion to the RUP fraction of each feedstuff. However, there is still a void in the intestinal digestion of RUP data in regard to certain feedstuffs that needs to be rectified. It is important to note that certain models such as the Cornell Net Carbohydrate Protein System (CNCPS) that are commonly used in the dairy industry are still using a constant of 80% for intestinal digestion of RUP. In addition, as new protein sources are incorporated into ruminant diets, they will need to be evaluated for RUP and intestinal protein digestion. These values will help producers make educated economical decisions on use of protein in the diets that they formulate for their animals. Using the various tools that we have at our disposal for measuring ruminal fermentation and intestinal protein digestion, our goals/objectives are to: 1. Evaluate various chemical properties of feedstuffs and modifiers of microbial metabolism and their effects on protein synthesis, protein degradation and fermentation by ruminal microbes and 2. Develop a comprehensive data base for measurement of intestinal protein digestion of ruminally undegraded dietary protein that can be incorporated into nutritional models for feeding protein to ruminants.
Project Methods
Previous research in my laboratory has resulted in development of relatively low cost, less labor intensive procedures to measure ruminal microbial protein synthesis and degradation, and intestinal protein digestion. These procedures include the use of an elaborate dual flow continuous culture system that simulates the rumen and has proven to be an effective rumen model and a unique research tool. A three-step in situ/in vitro procedure was also developed that estimates intestinal protein digestion and closely simulates physiological conditions of ruminants. We recently conducted a study using ruminally cannulated dairy cows and observed that supplementing dairy cows with active dry yeast (Saccharomyces cerevisae) increased the mean, minimum and maximum ruminal pH; decreased time spent in subacute rumen acidosis, and tended to decrease total VFA concentration in the rumen compared with control cows. Based on these observations, we will conduct a study using the dual flow continuous culture system to determine the effects of supplementing active dry yeast (Saccharomyces cerevisae) on nutrient metabolism by ruminal microbes and effects on pH. Four fermenters will receive buffer in the form of artificial saliva at a normal rate of 1.7 ml/min, while the other four will receive buffer + yeast at the same rate. Based on a dose of .5 g of yeast/cow/day and assuming a DM intake of 20 kg, fermenters will receive 1.9 mg of yeast/day (in two pulses of 0.95 mg) to mimic the dose of yeast for a "real" cow. Measurements of pH will be monitored every 10 minutes throughout the day and at the end of the 10-day experimental period fermentation parameters will be determined. The three-step in situ/in vitro procedure that we developed was designed to 1) closely simulate physiological conditions of ruminants, including potential effects of ruminal fermentation; 2) be rapid, reliable, and inexpensive; 3) be applicable to a wide variety of protein supplements; and 4) accurately reflect differences in CP digestion. Since developing this procedure, we have analyzed various animal protein sources, by-product protein sources, heat processed soybean products and commonly used protein sources such as soybean meal, cottonseed meal and sunflower meal. Our data base for measurements of intestinal protein digestion is continually expanding. For example, we are currently evaluating samples from Sweden including crushed barley, crushed peas, expeller processed rapeseed, hempseed cake and heat processed hempseed cake. We also will evaluate the effect of steam heat processing of hempseed cake at different temperatures on ruminal protein degradation using an autoclave set at 110, 120 and 130 C for 30 minutes and comparing theses samples with unprocessed hempseed cake. Compilation of all the protein sources that we have evaluated for ruminal protein degradation and intestinal protein digestion in the past 13 years will make a significant contribution to the nutritional models for feeding protein to ruminants that have not accounted for this very important variable and should increase the accuracy of their predictions.

Progress 01/01/12 to 12/31/12

Outputs
OUTPUTS: This year's research project resulted in abstracts in the Journal of Dairy Science and two publications in a refereed journal (Asian-Aust. J. Anim. Sci.) . PARTICIPANTS: Martin Ruiz Moreno, Ph. D., Elizabeth Seitz, Gail Carpenter and Sam Fessenden, M.S students from the University of Minnesota, respectively and G. I Crawford, Extension University of Minnesota. TARGET AUDIENCES: Research Scientists, Dairy Producers, Consulting Dairy Nutritionists and Feed Industry Representatives. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
In ruminants, excess dietary S is associated with several conditions including a reduction in DM intake, negative effects on feedlot performance and carcass characteristics, and sulfur-associated polioencephalomalacia. Therefore, ruminant nutritionists are interested in methods to reduce negative effects of high S diets. Bismuth subsalicylate (BSS) has been shown to decrease fecal H2S production in humans, while there are conflicting results about the effect of monensin (MON) on H2S production in ruminants. Therefore, the objective of Experiment 1 was to evaluate effects of these compounds on H2S production by rumen microbes. Eight dual flow continuous culture fermenters were used during 2 consecutive 10-d periods with the first 7 days for stabilization followed by 3 days of sampling. Addition of BSS to the diet increased (P < 0.05) digestion of OM, NDF and ADF but decreased (P < 0.05) NFC digestion and total VFA concentrations. Molar proportions of acetic and propionic acid increased (P < 0.05) with BSS, while butyric acid decreased (P < 0.05). Headspace concentration of H2S was reduced 99% (P < 0.05) with BSS. Fermenter pH mean, minimum and maximum increased (P < 0.05). Results indicate that BSS can markedly decrease H2S production in long term in vitro rumen incubations. Fermentation biomass (FB) is a dried bacterial co-product derived from lysine production (Ajinomoto Heartland, Inc.). The objective of Experiment 2 was to determine if FB can be used as a protein source in ruminant diets. Substrate for microbes in continuous culture fermenters was provided by one of two isonitrogenous diets, a control (CON) or dried fermentation biomass (DFB). Nitrogen source had no effect (P > 0.1) on total-N, dietary-N, and bacterial-N flows. Addition of FB decreased (P < 0.05) ammonia-N flow from 0.41 to 0.23 g/d and tended to decrease (P =0.06) effluent ammonia concentration from 17.1 to 9.7 mg/100 mL. Histidine and methionine flows increased (P < 0.05) from 0.48 to 0.53 and 0.18 to 0.20 g/d, respectively, when FB partially replaced SBM in the diet, but there were no effects (P > 0.1) on other AA or total AA. Results indicate that FB elicited a similar response in N metabolism and AA flows to SBM and may be used as a protein source in ruminant diets.

Publications

  • Riasi, A, M. Danesh Mesgaran, M.D. Stern, and M.J. Ruiz Moreno. 2012. Effects of two halophytic plants (Kochia and Atriplex) on digestibility, fermentation and protein synthesis maintained in continuous culture. Asian-Aust. J. Anim. Sci. Vol. 25, No. 5:642-647.
  • Karlsson, L., M. Ruiz-Moreno, M. D. Stern, and K. Martinsson . 2012. Effects of temperature during moist heat treatment on ruminal degradability and intestinal digestibility of protein and amino acids in hempseed cake. Asian-Aust. J. Anim. Sci. Vol. 25 No. 11:1559-1567.
  • M. Ruiz-Moreno,* E. Binversie, and M. D. Stern. 2012. Effect of monensin and bismuth subsalicylate on hydrogen sulfide in continuous culture fermenters. J. Dairy Sci. Vol. 95, Suppl. 2:622.
  • Carpenter, A., E. Binversie, M. Ruiz-Moreno, J. Usry, I. Shinzato, and M. D. Stern. 2012. Effect of dried fermentation biomass on microbial fermentation in continuous culture. J. Dairy Sci. Vol. 95, Suppl. 2:623.


Progress 01/01/11 to 12/31/11

Outputs
OUTPUTS: This year's research project resulted in four abstracts in the Journal of Dairy Science and one proceedings manuscript at the 2011 Minnesota Dairy Health Conference. PARTICIPANTS: Martin Ruiz Moreno, Elizabeth Seitz, Ph. D.and M.S students from the University of Minnesota, respectively and G. I Crawford, Extension University of Minnesota. TARGET AUDIENCES: Research Scientists, Dairy Producers, Consulting Dairy Nutritionists and Feed Industry Representatives. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
In Exp 1, an in vitro rumen fluid incubation was conducted using differing dietary concentrations of roughage (R) and sulfur (S) in a 3 x 2 + 2 factorial arrangement of treatments during 4 consecutive 24-h periods. Isonitrogenous dietary treatments included a corn-based control diet with no distillers grains (DG), 9% R, and 0.18% S (CON); a high R treatment with 27% R, 40% DG and 0.50% S (HRHS), and 6 treatments arranged in a 3 x 2 factorial with 3 S concentrations (0.3, 0.4, and 0.5%; LS, MS, HS, respectively), and 2 R concentrations (3 and 9%, LR and MR, respectively). Grass hay served as the roughage source and S concentrations were achieved through combination of 2 DG with differing S concentrations. At 5 and 24-h post-incubation, gas production was measured and a subsample of headspace gas was analyzed for hydrogen sulfide (H2S). Final pH was measured at the end of each 24-h incubation. Results indicate that DG inclusion generally increased batch culture pH, and compared with CON, the MS and HS treatments had higher total &#956;g H2S and &#956;g H2S/mL gas. Excessive release of rumen hydrogen sulfide (H2S) has been associated with sulfur-induced polioencephalomalacia. Bismuth subsalicylate (BSS) has been used to decrease H2S production in humans but its effect on rumen H2S production is unknown. In Exp 2, an in vitro rumen incubation was conducted to assess the effect of 5 levels of BSS on H2S release and rumen metabolism during 2 consecutive 24-h periods. A diet consisting of 50% corn, 40% dried distillers grains, 9.75% hay and 0.25% mineral premix provided substrate for microbial metabolism. Chemical grade BSS was added to a final concentration of 0 (Control), 0.5, 1, 2 and 4% of DM. Rumen fluid was obtained from a cannulated dairy cow and mixed with McDougall's saliva to a 1:2 ratio. Treatments were assigned in five replicates to 120-mL serum bottles containing 50 mL of the inoculum mix and 0.5 g of dietary DM. Bottles were flushed with N2, crimp sealed and incubated during 24 h at 39.1 degrees C. At the end of incubation, gas volume and H2S in the headspace of bottles were quantified. Final pH was recorded and incubation fluid was analyzed for NH3-N and VFA. Final pH increased (P < 0.05) with 2 and 4% BSS by 0.06 and 0.22 pH units, respectively. No effect (P > 0.05) of BSS on NH3-N concentration was observed. At 4% of DM, BSS decreased (P < 0.05) total VFA concentration by 15% and molar proportion of propionic acid by 5.7% while increasing acetic acid by 1.5% and the A:P ratio from 2.4 to 2.6, compared with the control. With 2% BSS, molar proportion of butyric acid was 9% lower than the control (P < 0.05). Concentration of branched-chain VFA was 19% higher (P < 0.05) with the addition of 0.5% BSS, compared with the control. All levels of BSS increased (P < 0.05) valeric acid molar proportion compared with 0% BSS. Compared with the control, gas production decreased (P < 0.05) with the addition of 2 and 4% BSS by 12 and 25%, respectively. All concentrations of BSS reduced (P < 0.05) H2S production by 18, 24, 82 and 99% for 0.5, 1, 2 and 4% BSS, respectively. Results indicate that BSS can markedly decrease H2S production.

Publications

  • Boucher, S. E., S. Calsamiglia, M. D. Stern, C. M. Parsons, H. H. Stein, C. G. Schwab, K. W. Cotanch, J. W. Darrah, and J. K. Bernard. 2011. Method evaluation for determining digestibility of rumen undegraded amino acids in blood meal. J. Dairy Sci. 94 (E. Suppl.). E-388.
  • Ruiz-Moreno, M., E. Seitz, M. D. Stern, and J. Garrett. 2011. In vitro modification of ruminal and post ruminal metabolism by lignosulfonate and polysaccharide protected microminerals. J. Dairy Sci. 94 (E. Suppl.). E-388.
  • Seitz, E., A. Carpenter, M. Ruiz-Moreno, M.D. Stern, G.I. Crawford. 2011. Effect of dietary roughage and sulfur concentration on hydrogen sulfide production from corn-based diets containing dried distillers grains. J. Dairy Sci. 94 (E. Suppl.). E-390-391.
  • Ruiz-Moreno, M., E. Seitz, and M. D. Stern. 2011. In vitro mitigation of rumen hydrogen sulfide. J. Dairy Sci. 94 (E. Suppl.). E-259. Stern, M. D. 2011. Rumen Physiology. Proc. Minnesota Dairy Health Conference: pp 100-118.


Progress 01/01/10 to 12/31/10

Outputs
OUTPUTS: This year's research project resulted in two abstracts in the Journal of Dairy Science. PARTICIPANTS: Martin Ruiz Moreno, Ph. D. student from the University of Minnesota. TARGET AUDIENCES: Research Scientists, Dairy Producers, Consulting Dairy Nutritionists and Feed Industry Representatives. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
In Exp 1, effects of Saccharomyces cerevisiae (SC) on rumen fermentation were evaluated using eight fermenters inoculated with ruminal fluid from a dairy cow in early lactation. Fermenters were provided with 75 g of DM/d of a diet formulated for a dairy cow producing 40 kg milk/d, 3.8 % fat, 3.7% protein. Two levels of SC (Levucell, SC20, Lallemand) at 0 or 2 mg/fermenter/day (SC0 and SC2, respectively) were infused twice a day at 0900 and 2100 h to the fermenters in a completely randomized arrangement of treatments. The latter concentration would be equivalent to supplementing 0.5 g/d of SC to a dairy cow. Apparent and true OMD were not affected (P > 0.05) by SC averaging 55.6 vs 56.0 and 65.5 vs 64.7% for SC0 and SC2, respectively. Similarly, no differences (P > 0.05) were obtained in NDF and ADF digestibility (51.1 vs 49.4% and 50.3 vs 48.1% for SC0 and SC2, respectively) or in total VFA concentrations (140.2 and 140.8 mM for SC0 and SC2, respectively). The addition of SC resulted in a lower (P < 0.05) NH3-N concentration and NH3-N flow (6.28 vs 3.85 mg/100 mL and 0.19 vs 0.12 g/d for SC0 and SC2, respectively. Average and minimum pH of fermenters did not differ between treatments (P > 0.05) but a trend (P < 0.1) for a lower maximum pH was obtained at 5.78 vs 5.71 for SC0 and SC2, respectively. A low dose of SC may benefit NH3-N metabolism, without having any negative effects on in vitro rumen fermentation. Hydrogen sulfide (H2S) release in the rumen depends upon ruminal pH, sulfur availability and its interaction with other minerals. In Exp 2, an in vitro rumen fluid incubation was conducted using two sources of S, Zn, Cu and Mn in a 2 x 2 factorial arrangement of treatments during 2 consecutive 24-h periods. A synthetic diet provided substrate for microbial metabolism. Sulfur was added as NaSO4 or sulfur-bound lignosulfonate to a final concentration of 0.75% of DM. Copper, Zn and Mn were added as CuSO4, ZnSO4 and MnSO4 or as protected Cu, Zn and Mn (SQM protected minerals, Qualitech, Inc.) to a final concentration of 16, 56 and 71 ppm of DM, respectively. Rumen fluid was mixed with McDougall's artificial saliva to a 1:4 ratio. Treatments were assigned in six replicates to 120-mL serum bottles containing 40 mL of the inoculum mix and 0.5 g dietary DM. Serum bottles were flushed with N2, sealed, and incubated for 24 h at 39.1 degrees C. Interactions between lignosulfonate and mineral source were detected. Addition of SQM minerals and lignosulfonate resulted in lower pH (P < 0.05) than that without lignosulfonate (5.87 vs 5.95, respectively), while absence of SQM minerals resulted in intermediate pH of incubations despite lignosulfonate (5.90 plus/minus 0.04). Addition of lignosulfonate without SQM minerals decreased total gas production (P < 0.001) compared to the other treatments (173.1 vs 175.9 mL/g OM). Lignosulfonate resulted in a lower (P < 0.001) production of H2S (416.2 vs 475 ug/g OM). In contrast, addition of SQM minerals increased (P < 0.001) production of H2S (469.5 vs 421.5 ug/g OM). The impact of mineral sources on H2S production should be considered when formulating diets for lactating cows.

Publications

  • Ruiz-Moreno, M., E. Seitz, J. Garrett and M. D. Stern and J. Sullivan. 2010. Hydrogen sulfide release by ruminal microbes maintained in batch culture. J. Dairy Sci. Vol. 93, E-Suppl. 1:429-30.
  • Ruiz-Moreno, M., M. D. Stern and J. Sullivan. 2010. Effects of low dose of Saccharomyces cerevisiae on metabolism by ruminal microbes in dual flow continuous culture fermenters. J. Dairy Sci. Vol. 93, E-Suppl. 1:425.


Progress 01/01/09 to 12/31/09

Outputs
OUTPUTS: This year's research project resulted in three publications in the Journal of Dairy Science. PARTICIPANTS: Sarah Boucher, Ph. D. student from the University of New Hampshire, Chuck Schwab, Professor from the University of New Hampshire, Professor Sergio Calsamoglia from the University of Barcelona, Spain; Professors Hans Stein and Carl Parsons from the University of Illinois, and Martin Ruiz Moreno, Ph. D. student from the University of Minnesota. TARGET AUDIENCES: Research Scientists, Dairy Producers, Consulting Dairy Nutritionists and Feed Industry Representatives. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
In Exp 1, five sources of Dried Distiller Grains with Solubles (DDGS) and 5 sources of Fish Meal (FM) were obtained from Feed Analysis Consortium, Inc. (Champaign, IL). To obtain the rumen-undegradable protein fraction, samples were ruminally incubated in situ for 16 h in 4 lactating cows, and the collected rumen-undegraded residues (RUR) were pooled by sample. Subsamples of the intact feeds and RUR were crop-intubated to 4 cecectomized roosters, and total excreta were collected for 48 h. Intact feeds, RUR, and excreta were analyzed for AA. Basal endogenous AA loss estimates were obtained from fasted birds and were used to calculate standardized digestibility of RUP-AA and AA in the intact feeds. Results indicate that standardized digestibility of feed-AA differs from RUPAA for DDGS samples but not for FM samples, and that standardized digestibility of individual AA differs within samples. Results also indicate that DDGS and most FM samples do not contain a constant protein fraction that is both undegradable in the rumen and indigestible in the small intestine. Indigestibility values of RUR were lower than in intact feeds, suggesting that the feed ingredients used in this experiment contain a protein fraction that is indigestible in the intestine but partly degradable in the rumen or digestible in the intestine after rumen incubation, or both. In a second experiment, 3 soybean meal, 5 DDGS, and 5 FM samples were used to evaluate the modified 3-step in vitro procedure (TSP) and the in vitro immobilized digestive enzyme assay (IDEA; Novus Intl Inc., St. Louis, MO) for estimating digestibility of AA in rumen-undegraded protein (RUP-AA). In a previous experiment, each sample was ruminally incubated in situ for 16 h, and in vivo digestibility of AA in the intact samples and in the rumen-undegraded residues (RUR) was obtained for all samples using the precision-fed cecectomized rooster assay. For the modified TSP, 5 g of RUR were weighed into polyester bags, which were then heat-sealed and placed into Daisy II incubator bottles. Samples were incubated in a pepsin/HCl solution followed by incubation in a pancreatin solution. After this incubation, residues remaining in the bags were analyzed for AA, and digestibility of RUP-AA was calculated based on disappearance from the bags. In vitro RUP-AA digestibility estimates obtained with this procedure were highly correlated to in vivo estimates. Corresponding intact feeds were also analyzed via the pepsin/pancreatin steps of the modified TSP. In vitro estimates of AA digestibility of the feeds were highly correlated to in vivo RUP-AA digestibility, suggesting that feeds may not need to be ruminally incubated before determining RUP-AA digestibility in vitro. The RUR were also analyzed via the IDEA kits and were good predictors of RUP-AA digestibility. However, the IDEA values of intact feed samples were highly correlated to in vivo RUP-AA digestibility, suggesting that the IDEA value of intact feeds may be a better predictor of RUP-AA digestibility than the IDEA value of the RUR. In conclusion, the modified TSP and IDEA kits are good approaches for estimating RUP-AA digestibility.

Publications

  • Boucher S. E., S. Calsamiglia, C. M. Parsons, M. D. Stern, M. Ruiz Moreno, M. Vazquez-Anon,and C. G. Schwab. 2009. In vitro digestibility of individual amino acids in RUP: The Modified three-step procedure and the immobilized digestive enzyme assay. J. Dairy Sci. 92:3939-3950.
  • Boucher, S.E., S. Calsamiglia, C.N. Parsons, H.H. Stein, M.D. Stern, P.S. Erickson, P.L. Utterback and C.G. Schwab. 2009. Intestinal digestibility of amino acids in rumen undegraded protein estimated using a precision-fed cecectomized rooster bioassay: I. soybean meal and soyplus. J. Dairy Sci. 92:4489-4498.
  • Boucher, S.E., S. Calsamiglia, C.N. Parsons, H.H. Stein, M.D. Stern, P.S. Erickson, P.L. Utterback and C.G. Schwab. 2009. Intestinal digestibility of amino acids in rumen undegraded protein estimated using a precision-fed cecectomized rooster bioassay: II. Distillers dried grains with solubles and fish meal. J. Dairy Sci. 92:6056-6067.


Progress 01/01/08 to 12/31/08

Outputs
OUTPUTS: This year's research project was presented as a research presentation at the Annual American Society of Animal Science/American Dairy Science Association Meetings in Indianapolis, IN. PARTICIPANTS: Sarah Boucher, Ph. D. student from the University of New Hampshire, Chuck Schwab, Professor from the University of New Hampshire, Professor Sergio Calsamoglia from the University of Barcelona, Spain; Professors Hans Stein and Carl Parsons from the University of Illinois, and Martin Ruiz Moreno, Ph. D. student from the University of Minnesota. TARGET AUDIENCES: Research Scientists, Dairy Producers, Consulting Dairy Nutritionists and Feed Industry Representatives. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
Three soybean meal (SBM), 3 SoyPlus, 5 dried distillers grains with solubles (DDGS), and 5 fishmeal (FM) samples were obtained from FeedAC, Inc. to evaluate the modified three-step in vitro procedure (TSP) for estimating digestibility of rumen undegraded (RU) amino acids (AA). Each sample was incubated in situ for 16 h in the rumen of 4 cows averaging (mean +/- SD) 48 +/- 4 d in milk, fed a 55% forage, 45% concentrate diet. Rumen undegraded residues were collected and pooled by feed sample, and sub-samples were analyzed for AA. A sub-sample of each residue was also tube fed to cecectomized roosters (4 birds per sample), and endogenous AA losses were estimated from fasted birds. Standardized digestibility (STD) of RUAA was calculated. Subsamples of each residue were also analyzed via the modified TSP. Digestibility of RUAA was calculated based on disappearance from the bags. Digestibility of RU lysine, methionine, total AA, and total essential AA were correlated to STD estimates measured in the roosters (R2 = 0.94, 0.83, 0.93, and 0.92, respectively. In conclusion, the modified TSP may be a good approach for predicting RUAA digestibility in SBM products, DDGS, and FM.

Publications

  • Boucher, S. E., S. Calsamiglia, M. D. Stern, , C. M. Parsons and C. G. Schwab. 2008. Digestibility of rumen undegraded amino acids estimated in cecectomized roosters and the modified three-step in vitro procedure. J. Dairy Sci. 91 (Suppl. 1):588.


Progress 01/01/07 to 12/31/07

Outputs
OUTPUTS: This year's research project was presented as a research presentation at the Annual Colorado Dairy Nutrition Conference in January and as a poster at the 2007 conference on Gastrointestinal Function in Chicago IL in April. In addition, two posters were presented at the 2007 Annual Meetings of the American Society of Animal Science/American Dairy Science Association in San Antonio, Texas in July. PARTICIPANTS: Alex Bach, Visiting Professor from Barcelona, Spain; Martin Ruiz Moreno, Ph. D. student and Melissa Thrune, M. S. student. TARGET AUDIENCES: Research Scientists, Dairy Producers, Consulting Dairy Nutritionists and Feed Industry Representatives.

Impacts
In general, rumen undegradable protein elicited various responses on microbial fermentation in the rumen, while Yucca schidigera extract had minimal effect on microbial fermentation. Previous experiments have shown some effects of Yucca schidigera extract on fermentation by rumen microbes at a higher dose equivalent of 2 g/d. Therefore, responses to Yucca schidigera extract may be dose dependent. Dual-flow continuous culture fermenters were used to assess differences in degradation pattern and ability to promote bacterial growth from the soluble crude protein fractions of canola meal, soybean meal and fish meal. Bacterial nitrogen flow was greatest with fish meal compared with the other soluble crude protein fractions. Results indicate that microbial degradation of the soluble crude protein fraction of fish meal appears to be higher than the soluble crude protein fractions of canola meal and soybean meal and can impact the choice of protein supplement to use in the ruminant diet.

Publications

  • Moreno, M. and M. D. Stern. 2007. Effects of rumen undegradable protein and Yucca schidigera extract on metabolism by ruminal microbes maintained in dual flow continuous culture fermenters. Microbial Ecol. in Health and Disease, 19:50.
  • Ruiz Moreno, Bach, M. Thrune, M. D. Stern. 2007. Evaluation of the fermentation dynamics of the soluble protein fraction of three protein sources in continuous culture fermenters. J. Anim. Sci. Vol. 85, Suppl. 1/J. Dairy Sci. Vol. 90, Suppl. 1:103.
  • Stern, M. D., S. Calsamiglia, A. Bach and M. Ruiz Moreno. 2007. Significance of Intestinal Digestion of Dietary Protein. Proc. 18th Annual Colorado Dairy Nutr. Conf. E: pp. 1-18.


Progress 01/01/06 to 12/31/06

Outputs
An experiment was conducted to determine the effects of rumen undegradable protein (RUP) and supplementation of Yucca schidigera extract on fermentation by ruminal microbes maintained in dual flow continuous culture fermenters. Eight fermenter flasks (1.03 L in volume) were inoculated with ruminal fluid from a cannulated cow during two 10-d experimental periods. Isoenergetic and isonitrogenous diets were formulated with two sources of supplemental protein, solvent-extracted soybean meal and mechanical-extracted soybean meal processed with fresh soy gums (Soy Best - registered trademark) to attain low RUP (LRUP) and high RUP (HRUP) diets. In addition, there were two concentrations of Yucca schidigera extract added to the LRUP and HRUP diets at 0 (0YS) and 50 (50YS) mg/kg of DM. The latter concentration would be equivalent to supplementing 1 g/d of Yucca schidigera extract to a dairy cow. The LRUP (28.2% RUP) and HRUP (41.1% RUP) diets, along with the two concentrations of Yucca schidigera extract were randomly assigned in a 2 x 2 factorial arrangement of treatments with two replicates per period. After a 7 day adaptation period, the last 3 days of each experimental period were used to collect effluents for chemical analyses. Differences in digestion (P < 0.05) between LRUP and HRUP diets, respectively, were observed for apparent OM (29.5 vs 24.4%), true OM (43.4 vs 38.3%) and NDF (33.0 vs 22.2%). There was a tendency (P < 0.10) for ADF digestion to also be higher with the LRUP diets (40.9 vs 34.2%). Because of greater digestion with the LRUP diets, total VFA concentration (mM) was greater (P < 0.05) at 142.3 vs 126.0. Ammonia-N (mg/100 mL) was greater (P < 0.05) with the LRUP diets (8.9) compared with the HRUP diets (5.4) while dietary N flow (g/d) was less (P < 0.05) with the LRUP diets (1.61 vs 1.88). There were no differences in bacterial N flow between RUP treatments or Yucca schidigera extract treatments. In this experiment, there were no interactions between RUP and Yucca schidigera extract supplementation. In general, RUP elicited various responses, while the dose of Yucca schidigera extract had minimal effect on microbial fermentation.

Impacts
Previous experiments have shown some effects of Yucca schidigera extract on fermentation by rumen microbes at a dose equivalent to 2 g/d. Therefore, responses to Yucca schidigera extract may be dose dependent and can possibly alter fermentation in the rumen.

Publications

  • Stern, M. D., A. Bach and S. Calsamiglia. 2006. New concepts in protein nutrition of ruminants. Proc. 21st Annual Southwest Nutrition & Management Conference Proceedings. pp. 45-66.
  • Ruiz Moreno and M. D. Stern. 2006. Effects of rumen undegradable protein and Yucca schidigera extract on metabolism by ruminal microbes maintained in dual flow continuous culture fermenters. To be presented at the 2007 Conference on Gastrointestinal Function, Chicago, IL.


Progress 01/01/05 to 12/31/05

Outputs
In study one, a three-step procedure was used to evaluate the effects of soybean meal processing on ruminal crude protein (CP) degradation and intestinal CP digestion. This procedure was used to evaluate seven soybean meal (SBM) products including solvent-extracted SBM (SE), mechanical-extracted (ME) SBM #1 with fresh soy gums (ME1G), ME SBM #2 (ME2), ME SBM #3 (ME3), ME SBM extruded (MEE), SE heat treated (SEH), SE nonenzymatically browned (SENB). Ruminal undegradable CP (RUP) was 23.2, 49.3, 42.1, 33.4, 38.3, 52.3 and 68.3% for SE, ME1G, ME2, ME3, MEE, SEH and SENB, respectively. Intestinal CP digestion (ID) was 67.5, 83.8, 78.9, 75.7, 76.5, 65.4 and 57.7% for SE, ME1G, ME2, ME3, MEE, SEH and SENB, respectively, indicating that processing can overprotect protein from digestion in the small intestine. Intestinally absorbable dietary protein (IADP), calculated as RUP x ID was 15.7, 41.3, 33.2, 25.2, 29.3, 34.2 and 39.4% for SE, ME1G, ME2, ME3, MEE, SEH and SENB, respectively. The range of IADP was 15.5% for SE to 41.3% for ME1G, however it is interesting to note that SENB was next highest at 39.4% because of a high RUP value that compensated for lower intestinal digestion. In study two, an experiment was done to determine the extent of ruminal degradation of a transgenic protein (Cry1Ab) expressed in kernels of maize (Zea mays) cultivar DKC53-32. Cracked kernels of transgenic maize (Bt+) were subjected to rumen digestion using in situ experiments with two ruminally cannulated Holstein cows. A non-transgenic maize cultivar (Bt-) was used as a control for crude protein (CP) degradation. CP and Cry1A concentrations from dacron polyester bags inserted in the rumen were determined for 48 h. The Bt- cultivar had greater CP content (P<0.05) than the Bt+ maize, but no difference (P>0.05) was found in ruminal degradable protein and the CP rate of degradation. The Cry1Ab protein was detected throughout ruminal digestion. The amount of Cry1Ab protein remaining after 16 and 24 h of ruminal degradation was 85 and 60%, respectively. In study three, the presence of patulin-producing Penicillium species in corn silage and high moisture corn, as well as adverse effects of patulin on microbial fermentation in continuous culture fermenters was studied. Penicillium species were isolated from 82% of samples and of these 3% produced the mycotoxin, patulin. Other molds identified were Mucor, aspergillus and Fusarium. Rumen microbes maintained in continuous culture fermenters were supplied with 0, 10, 20 or 40 mg of patulin every12 hours for three consecutive days. Increasing patulin reduced fiber digestion, true organic matter digestion, nonstructural carbohydrate digestion, protein digestion, bacterial nitrogen flows and total volatile fatty acid concentration. Conversely, ammonia nitrogen increased with increasing patulin indicating a decrease in efficiency of nitrogen utilization by the rumen microbes.

Impacts
Results from study one show that it is important to account for RUP and intestinal CP digestion when selecting a SBM source to include in the ruminant diet. Results from study two indicat that a significant fraction of Cry1Ab protein is not digested in the rumen. This is the first report of the rumen degradation rate of a transgenic protein. Results from study three show that Penicillium species molds are common contaminants of corn silage and high moisture corn and they produce patulin that can adversely affect fermentation by ruminal microbes. Alterations in microbial digestion of dry matter and production of microbial end-products impact the production and/or health of ruminants.

Publications

  • Bach, A., S. Calsamiglia and M. D. Stern. 2005. Nitrogen metabolism in the rumen. J. Dairy Sci. 88 (E. Suppl.).E9-E21.
  • Tapia, M. O., M. D. Stern, A. L. Soraci, R. Meonuck, W. Olson, S. Gold, R. L. Koski-Hulbert, and M. J. Murphy. 2005. Patulin-producing molds in fermented feeds and effects of patulin on fermentation by ruminal microbes in continuous culture. Anim. Feed Sci. Technol. 119:247-258.
  • Jacobs, J. L., F, Diez-Gonzalez, R. L. Phillips and M. D. Stern. 2005. Detection of transgenic maize Cry1Ab protein subjected to ruminal digestion. J. Anim. Feed Sci. 14(4):655-664.
  • Stern, M.D., M.R. Moreno and C.A. Macgregor. 2005. Effects of various methods used to process soybean meal on protein digestion in the rumen and small intestine. 2005 Conference on Gastrointestinal Function, Chicago, IL. Volume 2:24.


Progress 01/01/04 to 12/31/04

Outputs
Extensive research has been done to find less expensive and less invasive procedures for evaluating nutritional values of feeds for ruminant diets. Ideally, in vitro procedures are desirable compared with in situ and in vivo procedures. In vitro procedures that can be performed in the laboratory are more cost effective than procedures involving surgically cannulating animals for means of research. In vitro procedures are also noninvasive, which is desirable, as invasive procedures such as intestinally cannulating animals raise issues regarding ethical treatment of animals. In this study, an in situ technique using a ruminally cannulated cow was compared to an enzymatic in vitro procedure using similar retention times to compare crude protein (CP) digestion of different feeds. In addition, a comparison of intestinal CP digestion was done using the three-step procedure developed in our laboratory (Calsamiglia and Stern, 1995) with a 16 hour in situ ruminal residue, compared with an in vitro protease incubation procedure developed by McNiven et al. (2002) with a 4-hour in vitro residue followed with a modification of the pepsin-pancreatin procedure devoped in our laboratory. Five plant by-products were used that vary in ruminal degradability of protein, including corn gluten meal (CGM), sugarbeet pulp (SBP), citrus pulp, brewers' grains (BG) and distillers dried grains with solubles (DDGS). There is great interest in utilization of plant by-products as alternative sources of protein because of their availability and lower cost relative to other protein supplements. Results from this study showed that of the five feeds evaluated, CGM was highest in ruminally undegraded protein (RUP), demonstrated by in situ results. Following CGM, in decreasing order, were DDGS, BG, SBP and citrus pulp. In vitro results showed that SBP was highest in ruminal undegradable protein. Following SBP, in decreasing order, were CGM, BG, DDGS and citrus pulp. A comparison between in situ and in vitro procedures for evaluating protein degradation showed that degradation occurred more rapidly using the in vitro procedure, however the correlation coefficient between the in vitro and in situ procedures was 0.94 indicating that there was a good correlation between procedures.

Impacts
Results from this research, indicate that in vitro procedures have the potential to replace in situ procedures; however, further research using a greater variety of feeds needs to be done to standardize procedures. Implications are that if the procedure can be performed entirely in vitro, this would be more rapid and a surgically prepared animal would not be required for estimation of ruminal and intestinal protein digestion.

Publications

  • Mesgaran, M.D., Riasi, A. and Stern, M.D. 2004. Chemical composition, and in vitro and in situ protein digestibility of some halophytes located in central Iran. Proc. Brit. Soc. Anim. Soc., short communication, 2004:242.
  • Crawford, G.I., Stern, M.D., Hulbert, R.L.K., Caperoon, K.A. and Summer, P.G. 2004. Effects of a liquid byproduct nitrogen source on nitrogen utilization by ruminal microbesin continuous culture fermenters. J. Anim. Vet. Adv. 3(12):872-880.
  • Johnson, S. 2004. Evaluation of a ruminal in situ procedure vs an enzymatic in vitro procedure for estimating ruminal and intestinal protein digestion of various oilseed meals. Science in Agriculture Senior Thesis, University of Minnesota, St. Paul.
  • Wickham, S. 2004. Evaluation of a ruminal in situ procedure vs an enzymatic in vitro procedure for estimating ruminal and intestinal protein digestion of plant by-products. Science in Agriculture Senior Thesis, University of Minnesota, St. Paul.


Progress 01/01/03 to 12/31/03

Outputs
A liquid byproduct of monosodium glutamate (MSG) production, containing 13.7% N and 8.3% NH3N (DM basis) was evaluated as a nitrogen source for rumen microbes using eight dual-flow continuous culture fermenters. Two dietary treatments were utilized, with the primary N source being provided by soybean meal (SBM) in the first treatment, and the MSG byproduct (MSGN) in the second treatment. Each treatment was formulated to contain approximately 17% CP, 30% NDF, 17.5% ADF, and 5% fat (DM basis). The experiment consisted of one 10 d experimental period, including a 7 d stabilization phase followed by 3 d of sampling. Fermenter pH was maintained between 5.8 and 6.5 throughout the experiment. Measured pH was higher (P < 0.05) for SBM (5.83) than for MSGN (5.82). Digestion of ADF was 63.4 and 69.3% for SBM and MSGN, respectively, and tended to be higher (P = 0.06) for MSGN. Organic matter, CP, and NDF digestion were not affected (P > 0.05) by treatment. Efficiency of bacterial synthesis averaged 20.5 g of N/kg of OM truly digested, and was not different (P > 0.05) between treatments. Effluent concentration of NH3N was greater (P < 0.05) for MSGN (13.5 mg/100 mL) compared with SBM (2.4 mg/100 mL). Molar proportions of acetate (P = 0.07) and valerate (P = 0.08) tended to be higher for MSGN, while molar proportions of propionate tended (P = 0.07) to be higher for SBM. Total amino acid input and flow were higher for SBM, and total amino acid flow relative to input was greater for MSGN (P < 0.05).

Impacts
Results from this experiment indicate that the liquid byproduct of MSG production supported in vitro microbial growth similar to SBM and also increased ADF digestion. Therefore, when plant proteins are in limited supply there are possible non protein nitrogen sources available to the ruminant animal.

Publications

  • Crawford, G.I., Stern, M.D., Hulbert, R.L.K. and Summer, P.A. 2003. Effects of a liquid byproduct N source on fermentation by ruminal microbes in continuous culture fermenters. 2003 Conference on Gastrointestinal Function, Chicago, IL. Volume 1:33.
  • Crawford, G.I. 2003. Effect of various fat and protein sources on microbial fermentation in continuous culture of rumen contents. M.S. Thesis, University of Minnesota, St. Paul.
  • Nelsen, K.K., Crawford, G.I., Hulbert, R.L.K. and Stern, M.D. 2003. Chemical composition and small intestinal digestion of protein from various ruminal microbial fractions. 2003 Conference on Gastrointestinal Function, Chicago, IL. Volume 1:33.


Progress 01/01/02 to 12/31/02

Outputs
In Experiment 1, small sub-unit (SSU) rRNA-targeted oligonucleotide probes were used to monitor the persistence of a genetically engineered bacterium inoculated in model rumens. Eight dual flow continuous culture fermenters were operated with either standard artificial saliva buffer or buffer with chondroitin sulfate (0.5 g l -1) added. After 168 h of operation, fermenters were inoculated with Bacteroides thetaiotaomicron BTX (BTX), at approximately 1% of total bacteria. B. thetaiotaomicron was quantified using a species-specific probe and shown to persist in fermenters 144 h after inoculation (relative abundance 0.48% and 1.42% of total SSU rRNA with standard and chondroitin sulfate buffers, respectively). No B. thetaiotaomicron SSU rRNA was detected in fermenter samples prior to inoculation with strain BTX. Relative abundances of Bacteria, Eucarya and Archaea were not affected by either inoculation or buffer type. Chondroitin sulfate addition to the buffer increased bacterial nitrogen flow in fermenters, but did not alter nutrient digestion. Fiber digestion, in particular the hemicellulose fraction, increased after strain BTX addition. Total short chain fatty acid (VFA) concentrations were not altered by either buffer or inoculum but proportions of individual VFA differed. A second experiment was conducted to examine the chemical composition and small intestinal digestion of various rumen microbial fractions. These fractions included solid-associated bacteria (SAB), liquid-associated bacteria (LAB) and protozoa. Ash concentration (% of DM) was lower for protozoa (4.2) compared with SAB (12.1) but was not different between LAB (9.9) and SAB. Crude protein (% of OM) differed between the bacterial fractions in this study with LAB containing higher CP (70.2) compared with SAB (51.6), however CP of LAB was not different from protozoa at 60.2. Intestinal crude protein digestion was numerically greatest for protozoa (96.6%) followed by SAB (92.2%) and LAB (91.6%). Total amino acid concentration was numerically greatest for protozoa compared with SAB and LAB. The most obvious difference between microbial fractions was the relatively high amount of lysine for protozoa.

Impacts
Results from experiment 1 indicate that B. thetaiotaomicron BTX has the potential to increase ruminal fiber digestion, but further study is needed to determine effects on other fiber-digesting bacteria. Results from the second experiment demonstrated a high small intestinal digestibility of bacterial and protozoal protein. Because these data are lacking in the 2001 NRC for dairy cattle, results from this study can make a significant contribution in more accurately estimating protein requirements for dairy cattle.

Publications

  • Ziemer, C.J., Sharp, R., Stern, M.D., Cotta, M.A., Whitehead, T.R. and Stahl, D.A. 2002. Persistence and functional impact of a microbial inoculant on native microbial community structure, nutrient digestion and fermentation characteristics in a rumen model. Systemic and Appl. Microbiol. 25:416-422.
  • Kuha, K.K. 2002. Chemical composition and small intestinal protein digestibility of various rumen microbial fractions. Sci. in Agr. Undergraduate Thesis, University of Minnesota, St. Paul.


Progress 01/01/01 to 12/31/01

Outputs
A model rumen system, dual-flow continuous culture fermenters, was evaluated using ribosomal (r)RNA-targeted DNA probes to compare key microbial groups in samples vivo and in the fermenters. Fermenter samples had higher relative abundances of Bacteria 984.5%) and Archaea (2.1%) and lower relative abundances of Eukarya 91.8%) than ruminal samples (average 48.0% Bacteria, 1.3% Archea and 61.5% Eukarya). The relative abundance of Fibrobacter was similar between ruminal and fermenter samples, averaging 2.5%. In summary, fermenters were able to maintain a core prokaryotic community structure similar to the native microbial community in the rumen. Although protazoa populatiokns were lost, maintenance of Fibrobacter and archeal populations indicated that the model rumen system supported a functional community structure similar to the rumen. In a previous study, the mycotoxin, patulin, was inoculated into fermenters at 0, 30, 60 or 90 ppm with marked effects on organic matter (OM), crude protein (CP), and fiber digestion. In the current experiment, patulin was inoculated at 1, 10, 20 or 40 ppm. True OM digestion was lower in the 20 and 40 pp. patulin fermenters. All concentrations of patulin adversely affected fiber digestion while CP degredation was not different among treatments which was in contrast to the previous study. Total volatile fatty acid and acetate concentration (mm) were decreased by all concentrations of patulin in the current study.

Impacts
The model rumen system may serve as a suitable tool for studying aspects of ruminal microbial ecology and may resolve some of the relationships between community structure and function by providing control of experimental conditions. Penicillium species of mold such as patulin can have adverse effects on ruminal microbial metabolism at lower concentrations than previously studied.

Publications

  • Ziemer, C.J., Sharp, R., Stern, M.D., Cotta, M.A., Whitehead, T.R. and Stahl, D.A. 200. Comparison of microbial populations in model and natural rumens using 165 ribosomal RNA-targeted probes. Environmental Microbial. 2: 632-643.
  • Tapia, M.O. 2001. Patulin toxicity in sheep. Ph.D Disertations, University of Minnesota, St. Paul.


Progress 01/01/00 to 12/31/00

Outputs
Eight dual-flow continuous culture fermenters were used to study the effects of sodium bicarbonate and Acid Buf, a calcified seaweed product, on pH, microbial nitrogren metabolism and feed digestion. Dietary treatments were: 1) control diet, 2) control diet with .78% Acid Buf, 3) control diet with .49% Acid Buf, and 4) control diet with .78% sodium bicarbonate. The control diet had a 60:40 concentrate to forage ratio. The buffered diets did not alter pH of the fermenters compared with the control diet. The pH of the fermenters averaged below 6.0 for each of the diets throughout the experiment. No differences among treatments were observed for digestion of organic matter, protein or fiber. Molar percentages or total production of volatile fatty acids were not different among treatments. Ammonia-N production, effluent N flow, and bacterial synthesis of crude protein did not differ among treatments. Penicillium species of mold can be contaminants of fermented feeds that can produce mycotoxins, including patulin that are toxic to a wide range of living organisms including microbes, plants and animals. In another study, eight single-flow continuous culture fermenters were used to evaluate the influence of patulin on fermentation by ruminal microbes. Substrate for microbial metabolism was a diet consisting of 38% alfalfa hay, 28% corn silage, 27% cracked corn, 5% soybean meal and .6% of a mineral mix on a DM basis. During each period, two fermenters each were inoculated with 0, 30, 60 or 90 ppm of patulin every 12 hours for the last 3 days. Addition of patulin to the fermenters at all 3 levels decreased true organic matter, crude protein and fiber digestion by an average of 25, 23 and 44%, respectively with no differences among patulin levels. Bacterial N flow (g/d) was 1.13, .65, .65 and .44 for the 0, 30, 60 and 90 ppm patulin levels, respectively and was greater for the 0 ppm treatment compared with 30, 60, 90 ppm. Individual volatile fatty acid concentrations were also affected by patulin, most notably there was a decrease in acetate due to patulin addition.

Impacts
Buffer concentrations in high grain diets need to be further evaluated to determine effects on pH in the rumen. Penicillium species of mold such as patulin can have adverse effects on ruminal microbial protein synthesis and fermentation.

Publications

  • Aga, L.M., Koski, R.J. and Stern, M.D. 2000. Effects of buffers on pH and microbial metabolism in continuous culture of rumen contents. Proc. of 25th Conf. on Rumen Function. 25:33. (Abstract)
  • Tapia, M.O., Murphy, M.J., Koski, R.J. and Stern, M.D. 2000. Influence of patulin level on fermentation by ruminal microbes in continuous culture. Proc. of 25th Conf. on Rumen Function. 25:34. (Abstract)


Progress 01/01/99 to 12/31/99

Outputs
Eight single-flow continuous culture fermenters were used to study the effects of the type of energy source on ruminal nitrogen utilization from high quality pasture. The four dietary treatments included high quality grass and legume pasture alone, pasture plus soybean hulls, pasture plus beet pulp, and pasture plus corn. Diets supplemented with additional sources of energy (soybean hulls, beet pulp, and corn) were isocaloric but differed in the type and rate of carbohydrate fermentation. Energy supplements constituted 45% of the total dietary dry matter and were fed twice daily at 12-h intervals in place of pasture, which is characteristic of grain feeding at milking when animals are in a grazing situation. Energy supplementation reduced pH, ammonia nitrogen flow, and ammonia nitrogen concentration and increased bacterial nitrogen flow (as a percentage of nitrogen intake). The supplementation of corn and soybean hulls resulted in the highest microbial nitrogen flow (as a percentage of nitrogen intake). Corn had a tendency to reduce fiber digestion because of excessively low ammonia nitrogen concentrations. Beet pulp was similar to corn in that it decreased ammonia nitrogen concentrations. Supplementation of soybean hulls resulted in a more synchronized fermentation, greater volatile fatty acid production, and greater fiber digestion. In another study, eight dual-flow continuous culture fermenters were used to study the effects of feeding different levels of methionine and ruminally undegradable protein (RUP) on the amino acid (AA) profile of protein residue after microbial fermentation. Two dietary treatments, diets HmLr (high methionine, low RUP) and HmHr (high methionine, high RUP), were formulated to meet, but not exceed, more than 140% of each estimated individual AA requirement for milk production. Diets LmLr (low methionine, low RUP) and LmHr (low methionine, high RUP) were formulated to meet the estimated individual AA requirement except for methionine.

Impacts
With diets based on pasture, it may be more important to improve bacterial nitrogen flow and bacterial utilization of nitrogen than to maximize the efficiency of bacterial protein synthesis because better utilization of nitrogen by ruminal microorganisms results in higher bacterial nitrogen flow and higher fiber digestion. Because true microbial digestion of methionine, cystine, tyrosine, and isoleucine was reduced in the presence of high levels of methionine, supplementation of dietary methionine can increase flows of these amino acids to the duodenum.

Publications

  • Bach, A. and Stern, M.D. 1999. Effects of different levels of methionine and ruminally undegraded protein on the amino acid profile of effluent from continuous culture fermenters. J. Anim. Sci. 77:3377-3384.
  • Bach, A., Yoon, I.K., Stern, M.D., Jung, H.G. and Chester-Jones, H. 1999. Effects of type of carbohydrate supplementation to lush pasture on microbial fermentation in continuous culture. J. Dairy Sci. 82:153-160.


Progress 01/01/98 to 12/31/98

Outputs
A linear model, two mathematical nonlinear models, and a curve-peeling procedure were used to estimate rate and extent of ruminal crude protein degradation of meat and bone meal and soybean meal from data obtained using the in situ Dacron polyester bag technique. Most of the values for extent of crude protein degradation of meat and bone meal were lowest when determined using curve peeling or the nonlinear models. In general, rates and extents of crude protein degradation of meat and bone meal estimated using the linear model and including ruminal incubations up to 12 h were greater than those obtained with the linear model and including ruminal incubations up to 24 h or up to 72 h. In addition, the models ranked the meat and bone meal samples differently for rate and extent of crude protein degradation. The results of the lack-of-fit test indicated that the linear model was inappropriate for estimating rate of degradation of meat and bone meal. However, crude protein degradation for soybean meal could be described by the linear model if long ruminal incubation times (greater than 48 h) were included in the calculations. When using a specific mathematical model to predict crude protein degradation, analysis of residuals vs fitted and lack-of-fit tests should be performed to assess the validity of the model to describe the degradation patterns of the protein source under consideration. Also, long (at least 48 h) ruminal incubation times may be needed to correctly describe the pattern of crude protein degradation for meat and bone meal and other protein sources. In another study, Methanogen populations in the rumen and in model rumen systems (operated over a 240 h period) were studied using the small subunit (SSU) rRNA phylogenetic framework for group-specific enumerations. Representatives of the family Methanobacteriaceae were the most abundant methanogen population in the rumen, accounting for 89.3 percent of total archaea in the rumen fluid and 99.2 percent in a protozoal fraction of rumen fluid. Their percentage of archaea in the model rumen systems declined from 84 percent to 54 percent after 48 h of operation, correlated with loss of protozoa from these systems. Competitive relationships are key determinants of microbial community structure in the rumen. The techniques used for this study could be equally valuable for evaluating these various key microbial relationships. Because the nutrition of the host animal is largely determined by the products of the overall metabolism of this community (volatile fatty acids, bacterial protein and vitamins), the metabolic interactions that define the microbial community and its collective activities also determine host nutrition and production. We anticipate that information provided by the use of molecular techniques combined with established culture based enumerations and rumen fermentation characteristics will help resolve the contribution of microbial interactions to overall ruminal metabolism and host production.

Impacts
(N/A)

Publications

  • SHARP, R., ZIEMER, C. J., STERN, M. D. AND STAHL, D. A. 1998. Taxon-specific associations between protozoal and methanogen populations in the rumen and model rumen system. FEMS Microbial. Ecol. 26:71.
  • BACH, A., STERN, M. D., MERCHEN, W. R. AND DRACKLEY, J. K. 1998. Evaluation of selected mathematical approaches used to describe the kinetics of protein degradation in situ. J. Anim. Sci. 76:2885.


Progress 01/01/97 to 12/31/97

Outputs
A three step (rumen-pepsin-pancreatin) invitro procedure was developed to estimate intestinal digestion of proteins in ruminants. Differences among studies in animal species cannula placement, digestibility markers, and animal variation introduce considerable variation into what is designed to be the standard for evaluating the three step procedure. Relative to in vivo research, the three step in vitro procedure provides a low cost, rapid, and reliable method for estimating intestinal protein digestion of feedstuffs. Differences in intestinal digestion of proteins among and within various sources should be considered when determining protein value for ruminants.

Impacts
(N/A)

Publications

  • Stern, M. D., Bach, A., and Calsamiglia, S. 1997. Alternative techniques for measuring nutrient digestion in ruminants. J. Anim.


Progress 01/01/96 to 12/30/96

Outputs
In situ and in vitro procedures were used to determine ruminal degradation and intestinal digestion of crude protein from meat and bone meal, hydrolyzed feather meal, ring dried blood meal, and batch dried blood meal obtained rom various rendering and meat packing plants. Results demonstrated that large variations in ruminal degradation, intestinal digestion and intestinally absorbable dietary protein can occur among and within different animal byproducts. Menhaden fish meal (FM) samples from five processing plants were used to evaluate effects of preparation on ruminal degradation of FM protein. Results confirmed that preparation methods can significantly alter ruminal degradation of FM protein and that measurements of ruminal solubility can possibly be used as a predictor of ruminal degradation for FM protein. Continuous culture fermenters were used to study the effects of type of energy source on ruminal nitrogen utilization from lush pasture. Cracked corn, soybean hulls and beet pulp were used as energy supplements for a high quality 50:50 grass/legume pasture forage. Energy supplementation reduced pH, ammonia nitrogen flow and concentration, and increased bacterial nitrogen flow (as a % of nitrogen intake) demonstrating that energy supplementation can improve pasture nitrogen utilization.

Impacts
(N/A)

Publications

  • HOWIE, S.A., CALSAMIGLIA, S., AND STERN, M.D. 1996. Variation in ruminal degradation and intestinal digestion of animal byproduct proteins. Anim. Feed Sci. Technol. (In press).
  • YOON, I., LINDQUIST, K., HONGERHOLT, D., STERN, M., CROOKER, B., AND SHORT, K. 1996. Methods of processing menhaden fish meal and their effects on ruminal protein degradation assessed by various techniques. Anim. Feed Sci. Technol. 60:13-27
  • YOON, I.K. AND STERN, M.D. 1996. Effects of Saccaromyces cerevisae and Aspergillus oryzae on ruminal fermentation in lactating Holstein cows. J. Dairy Sci. 79:411-417.
  • BACH, A., YOON, I.K., STERN, M.D., JUNG, H.G., AND CHESTER-JONES, H. 1996. Effects of type of energy supplementation for lush pasture on microbial fermentation in continuous culture. J. Anim Sci. 74(Suppl. 1):88.


Progress 01/01/95 to 12/30/95

Outputs
Three mid lactation Holstein cows with ruminal and duodenal cannulas were used to determine whether ruminal or postruminal alterations in metabolism are responsible for changes in milk composition that frequently are associated with dietary fish meal. Cows were offered a diet of forage and concentrate that was supplemented with isonitrogenous amounts of soybean meal dosed into the rumen or fish meal dosed either into the rumen or into the duodenum. Milk yields were unaffected by treatment, but milk fat content decreased, and milk protein content increased when cows were supplemented with fish meal. Results from this experiment suggest that effects of fish meal on milk composition are due to postruminal alterations in metabolism. Dual flow continuous culture fermenters were used to study the effects of protein source on microbial fermentation. Results suggested that feeding a combination of soybean meal and corn gluten meal as protein supplement could result in increased dietary amino acid flow into the duodenum. Male Holstein calves were used to evaluate the effect of feeding starter and grower diets containing either soybean meal, calcium lignosulfonate treated soybean meal with corn or with soyhulls. Calves fed starter diets with treated soybean meal had higher average daily gain than other treatments for the first 91 d. There were no differences in calf performance in the remaining growing period. Soyhulls effectively replaced corn grain.

Impacts
(N/A)

Publications


    Progress 01/01/94 to 12/30/94

    Outputs
    Milk yield was not affected when corn was replaced with beet pulp at 15% of dietary dry matter or soybean meal with animal by-product meal at 25% of dietary crude protein. However, beet pulp depressed dry matter intake, and milk crude protein content and yield. Continuous culture fermenters were used to evaluate effects of extrusion of whole soybeans and changes in forage composition of diets on microbial fermentation. Changes in the ratio of alfalfa hay to corn silage and alteration of dietary soybean concentration affected true organic matter digestion and dietary crude protein degradation, but extrusion of whole soybeans had little effect on fermentation. Eight different protein supplements were evaluated for their effects on ruminal fermentation and crude protein digestion using dual flow continuous culture fermenters. Supplementation of diets with proteins low in ruminal degradability increased nonammonia nitrogen, dietary nitrogen, total and essential amino acid flow, and modified the amino acid profile flowing out of the fermenters. Seventeen Menhaden fish meal samples were used to develop equations to predict ruminal degradation of fish meal protein. Data demonstrated that a one variable model with solubles add-back provides an easy, fast, and inexpensive way to predict ruminal degradation of fish meal protein, and is highly correlated with in situ measurements.

    Impacts
    (N/A)

    Publications


      Progress 01/01/93 to 12/30/93

      Outputs
      Continuous culture fermenters were used to study the effects of diets containinglignosulfonate-treated soybean meal subjected to two pH treatments (pH controlled at 6.3 or uncontrolled) on microbial fermentation. Treatment of soybean meal with lignosulfonate protected protein from microbial degradation. When pH was uncontrolled, average daily pH was 5.9 (range 5.5 to 6.2) and the effect of lignosulfonate treatment on protein protection and other parameters was not detected. A three step procedure, including ruminal preincubation, pepsin digestion and pancreatic digestion, was developed to estimate postruminal digestion of proteins in cattle. The technique was validated using duodenal samples from which small intestinal digestion was previously determined in vivo. Results demonstrated that differences in postruminal digestion between various sources be considered when determining protein value for ruminants. In another study, the effects of supplemental yeast (Saccharomyces cerevisae) and fungal (Aspergillus oryzae) cultures on ruminal microbial fermentation, microbial population and nutrient supply to the small intestine of lactating cows were examined. Bacterial nitrogen flow to the small intestine was not affected by treatments; however, results showed that direct-fed microbial additives can alter the ruminal bacterial population and fermentation.

      Impacts
      (N/A)

      Publications


        Progress 01/01/92 to 12/30/92

        Outputs
        Forty-eight multiparous cows were assigned randomly to a total mixed ration formulated to contain 68 or 55% of dietary crude protein as ruminally degradable protein. Supplemental crude protein was soybean meal for the control diet or a combination of soybean meal, expeller-processed soybean meal and fish meal for the low degradable protein diet. Production of fat-corrected milk was not affected by dietary treatment. Cows fed the expeller-processed soybean meal and fish meal diet produced milk that contained less milk fat and milk protein than cows fed the control diet. In another study, these same diets provided substrate for microbial metabolism in dual flow continuous culture fermenters. True organic matter and dry matter digestion were not affected by dietary treatment. Although total volatile fatty acid concentration was not affected by dietary treatment, molar proportion of propionate was higher, and acetate and acetate to propionate ratio were lower, for expeller-processed soybean meal and fish meal diet. Partial replacement of soybean meal by expeller-processed soybean meal and fish meal decreased fiber digestion by rumen microbes and altered volatile fatty acid molar proportion in the effluent, but did not reduce ruminal degradation of dietary protein.

        Impacts
        (N/A)

        Publications


          Progress 01/01/91 to 12/30/91

          Outputs
          A dual flow continuous culture system was used to study effects of roasting fullfat soybeans and addition of various lipid sources on fermentation by rumen microorganisms. Main effects in the factorial design were protein source (roasted and steeped vs raw full fat soybeans) and lipid supplement. Lipid supplement treatments included: no supplemental lipid, 3% Megalac, 3% Megalac, 3% tallow and 3% corn oil. Supplementation of lipid resulted in higher total and individual fatty acid flow from the fermenters compared with the non-supplemental lipid control. Lipid source, regardless of ruminal inertness, had little effect on microbial fermentation. Roasting of full fat soybeans was not successful in protecting protein from microbial degradation. In another study, yeast culture, (Saccharomyces cerevisae) supplementation to diets containing different proportions of alfalfa hay and corn silage on ruminal microbial fermentation and microbial population was examined. Forage source x yeast culture interactions were not significant for any measurements. Total viable, proteolytic and cellulolytic bacterial numbers in fermenters were not affected by treatments. Yeast culture supplementation did not affect any of the variables measured in this experiment.

          Impacts
          (N/A)

          Publications


            Progress 01/01/90 to 12/30/90

            Outputs
            A dual flow continuous culture system was used to examine the effect of replacing plant protein-nitrogen with urea-nitrogen plus corn in diets containing predominantly alkaline hydrogen peroxide-treated wheat straw on bacterial protein synthesis and other fermentation measurements. Four diets consisted of 70% treated straw with urea-nitrogen replacing 0, 25, 50 and 75% of soybean meal-nitrogen. Results indicated that replacement of up to 25% of the supplemental plant protein-nitrogen with urea-nitrogen plus corn did not have a negative effect on ruminal bacterial growth and fermentation. In another experiment, concurrent in vivo and in vitro studies were conducted to evaluate urea, soybean meal, ground raw soybeans, extruded soybeans or extruded soybeans plus urea as primary supplemental nitrogen sources in starter diets for Holstein steers. Average daily gains for steers up to 181 kg body weight were similar for steers fed extruded soybeans plus urea, extruded soybeans alone and soybean meal but lower for those fed urea or ground raw soybeans. In continuous culture, dietary protein degradation was lowest for the extruded soybean diet while lysine flow was higher for the extruded soybean plus urea diet than for all diets except the extruded soybean diet. Results of these experiments indicate that extruded soybeans as a protected ruminal escape nitrogen source with or without added urea did not improve steer performance above that obtained from soybean meal in starter diets.

            Impacts
            (N/A)

            Publications


              Progress 01/01/89 to 12/30/89

              Outputs
              Eight dual flow continuous culture fermenters were used to compare alkaline hydrogen peroxide-treated wheat straw with other carbohydrate sources for ruminal microbial growth and fermentation. Diets contained either 70% nontreated wheat straw, cellulose, corn starch or treated wheat straw. Results from this experiment showed that when wheat straw was treated, degradation and fermentability of cell walls by ruminal bacteria were increased. Total bacterial nitrogen production was greater for the corn starch and treated straw diets indicating that treated straw was comparable to corn starch as an energy source for growth of ruminal bacteria. Another study examined the effects of protection method on protein degradation of soybean meal by ruminal bacteria. Treatments included solvent extraction (control), sodium hydroxide, ethanol, formaldehyde, expeller processing, propionic acid, extrusion and lignosulfonate. Crude protein degradation of formaldehyde-treated, expeller processed, propionic acid-treated, extruded and lignosulfonate-treated soybean meal diets were lower than the control diets. Total bacterial nitrogen output was lowest for soybean meal protected by formaldehyde, expeller processing and lignosulfonate treatments. Protection by formaldehyde, expeller processing, propionic acid and lignosulfonate treatments increased total amino acid flow compared with the control. Formaldehyde and expeller processing treatments also increased essential amino acid flow compared with the control.

              Impacts
              (N/A)

              Publications


                Progress 01/01/88 to 12/30/88

                Outputs
                Eight dual-flow continuous culture fermenters were used to determine amino acid profiles of effluent digesta when corn gluten meal, whole soybeans extruded at 149C, meat and bone meal and soybean meal were fed in various combinations. Results from this experiment showed that amino acid profiles of digesta leaving the rumen can be modified by feeding protein sources resistant to microbial degradation and that combinations of complementary resistant proteins could improve intestinal amino acid supply and balance. Another study examined the effect of soybean meal, Ca-lignosulfonate treated soybean meal, blood meal and feather meal, supplied individually or in combination in diets composed predominantly of alkaline hydrogen peroxide treated wheat straw, on ruminal microbial fermentation and amino acid flow. Results showed that diets which contained blood meal had lower organic matter and fiber digestion, ammonia N and VFA concentrations, and CP degradation but higher non-ammonia N, dietary N, total amino acid, and essential amino acid flows, compared to the soybean meal diets. Combining treated soybean meal and blood meal resulted in similar organic matter and fiber digestibilities compared to the soybean meal diets. Flow of certain individual amino acids, such as histidine and leucine, were higher with this combination. Results suggested that amino acid profiles of digesta leaving the rumen can be manipulated with diets containing low degradable protein along with a highly fermentable roughage.

                Impacts
                (N/A)

                Publications


                  Progress 01/01/87 to 12/30/87

                  Outputs
                  Continuous culture fermenters were used to study effects of forage source on ruminal bacterial nitrogen metabolism. Forages included alfalfa, cicer milk-vetch, birdsfoot trefoil and sainfoin. Bacterial degradation of protein was lowest for sainfoin, possibly due to the condensed tannins found in sainfoin which forms reversible bonds with the protein. Another study was conducted to evaluate calcium lignosulfonate-treated soybean meal as a source of rumen protected protein. Diets included untreated soybean meal (SBM), water-treated soybean meal (H(2)O-SBM), xylose-treated soybean meal (xylose-SBM) and lignosulfonate-treated soybean meal (LSO(3)-SBM) and were fed to Holstein cows fitted with ruminal and intestinal cannulae. Ruminal protein degradation was 70.6, 69.6, 55.8 and 53.7% for SBM, H(2)O-SGM, xylose-SBM and LSO(3)-SBM diets, respectively. Duodenal nonammonia-N flow and absorption of total amino acids (g/d) in the small intestine were generally not affected by treatment. Using the fermenters, efficiency of bacterial protein synthesis, total effluent bacterial N and organic matter and fiber digestion all increased when urea was supplemented to diets containing LSO(3)-SBM. In addition, diaminopinelic acid (DAPA) and purine concentrations and estimates of ruminal microbial activity from 13 experiments were evaluated. In general, purines produced lower estimates of ruminal microbial activity than DAPA, however, variability of these estimates was similar for the markers.

                  Impacts
                  (N/A)

                  Publications


                    Progress 01/01/86 to 12/30/86

                    Outputs
                    A study was conducted to compare ruminal bacterial protein synthesis and degradation using diaminopmelic acid (DAP) and purines as microbial markers in continuous culture fermenters. Ethanol treatment of soybeans lowered bacterial N and increased dietary N in the effluent due to a reduction in protein degradation from 85.9 to 70.1% determined by DAP analysis. In contrast, no differences were observed for the same variables using purines. Efficiency of bacterial protein synthesis was higher (34.7 vs 32.3 g N/kg OM digested) using purines with diets containing ethanol treated soybeans, however DAPA showed no such trend. In another study, methionine flow was 22% higher for N-acetyl-D, L-methionine compared to D,L methionine indicating a greater resistance to bacterial degradation of the methionine derivative. Using the fermenters, various nitrogenous supplements including urea, soybean meal, raw soybeans, extruded soybeans (ES) and extruded soybeans plus urea (ES + U) were examined for effect on fermentation. Degradation of dietary crude protein in the urea diet was 91 vs 64% for the extruded soybean diet while bacterial N production was highest (1571 mg/d) for the ES + U diet and lowest (1161 mg/d) for the ES diet. In addition, Holstein cows in early lactation were used to compare combinations of supplemental extruded soybeans and corn gluten meal to soybean meal. Milk yields ranged from 31.0 to 34.3 kg/d and were greatest for cows fed soybean meal compared to various combinations of the protected protein sources.

                    Impacts
                    (N/A)

                    Publications


                      Progress 01/01/85 to 12/30/85

                      Outputs
                      Eight dual flow continuous culture fermenters were used to study the effects of various factors on ruminal bacterial fermentation. Supplementation of a diet containing 60% grain and 40% forage (DM basis) with various cobalt (Co) sources at 1 ppm had no effect on carbodydrate or protein utilization. Supplementing Co at 10 ppm as Co glucoheptonate increased vitamin B(12) synthesis, neutral detergent fiber and acid detergent fiber digestion in high and low forage diets. Fermenters were also used to determine the effect of supplementation of methionine and various derivatives on effluent flow of methionine. Methionine flow was higher for D,L-methionyl-D,L-methionine compared to a control diet (no methionine supplementation). Using the fermenters, rate of protein degradation was found to be greater for linseed meal (LSM) than corn gluten meal (corn) with soybean meal intermediate (SBM). Calculated bypass of potentially digestible protein for SBM, LSM and CGM was 15.9, 10.9 and 29.2%, respectively. The effects of total nonstructural carbohydrate (TNC) and protein degradation on ruminal bacterial fermentation was also studied. Ammonia-nitrogen concentration was lower for low TNC diets than high TNC diets. Protein degradation was lower, while efficiency of bacterial protein synthesis was higher for the low TNC diets. Resistance of beet pulp in the low TNC diets and alcohol treated soybeans in the low protein degradation diets resulted in higher total amino acid flows.

                      Impacts
                      (N/A)

                      Publications


                        Progress 01/01/84 to 12/30/84

                        Outputs
                        A dual flow continuous culture system was used to examine the effects of variousfactors on rumen bacterial fermentation. Niacin nor niacinamide (100 mg/kg diet) had any effect on organic matter (OM) digestibility, total volatile fatty acid (VFA) concentration or bacterial protein synthesis. In one experiment, niacin supplementation increased total nonstructural carbohydrate digestibility and in another experiment, acid detergent fiber and cellulose digestibilities were higher with niacinamide supplementation. Fermenters were also used to determine the influence of protein source (corn gluten meal, meat and bone meal, heat-treated soybeans and soybean meal) on amino acids potentially available to ruminants. Higher total amino acid flows were observed with diets containing predominantly corn gluten meal compared to other test proteins, while combinations of corn gluten meal and heat-treated soybeans provided hgiher flows of arginine, leucine and phenylalanine compared to soybean meal. The effect of ammonium salts of volatile fatty acids (ASVFA) on fiber digestion was also examined. Ammonium salts of volatile fatty acids (68.5% ammonium salts of C-5 branched chain VFA and 31.5% ammonium isobutyrate) were supplementted at 0, .4, .8, 1.2 and 1.6% of the grain mix.

                        Impacts
                        (N/A)

                        Publications


                          Progress 01/01/83 to 12/30/83

                          Outputs
                          An experiment was conducted to examine the use of lignosulfonate to protect soybean meal protein from microbial degradation in continuous culture of rumen contents. Pelleting of soybean meal with 4% permeate reduced NH(3)-N and protein degradability from 5.14 to 4.36 mg/100 ml and 75.6 to 58.4%, respectively, compared to an untreated pelleted soybean meal diet. Dual flow continuous culture fermenters were also used to determine nitrogen utilization of alfalfa, birdsfoot trefoil and smooth bromegrass. Results from this experiment indicated that protein degradation and synthesis by the rumen microbes were higher for alfalfa. Another experiment was designed to compare rumen variables determined in continuous culture with those obtained in vivo. Soybean meal, raw soybeans and whole soybeans extruded at 132 and 149C provided 50% of the protein in diets which were comprised of 52% grain, 36% corn silage and 12% alfalfa hay (dry matter basis). These same diets were previously studied in vivo using lactating dairy cows fitted with rumen cannulae and t-type cannulae in the duodenum and ileum. Average values for true organic matter digestibility (%), degradability of crude protein (%) and bacterial synthesis (g N/kg OM truly digested) were 56, 70 and 42 in the rumen of cows and 58, 76 and 35 in continuous culture. Results from this study indicate that the dual flow continuous culture system gives reasonable estimates of in vivo ruminal fermentation.

                          Impacts
                          (N/A)

                          Publications


                            Progress 01/01/82 to 12/30/82

                            Outputs
                            Since the amount of protein supplied to the small intestine of ruminants is determined by the quantity of microbial protein synthesized in the rumen and protein escaping microbial degradation, it is important to optimize the contribution of each of these protein sources. An experiment has been designed to determine the optimal nonstructural carbohydrate (starches, sugars, fructosans) to degradable protein ratio for obtaining maximal protein synthesis in the rumen. Protein degradability in the rumen was determined by in situ procedures for six feedstuffs which had total nonstructural carbohydrate (TNC) values ranging from 10-75%. Ruminal protein degradation for corn, beet pulp, wheat middlings, wheat bran, barley and oats was 47, 43, 70, 72, 74 and 80%, respectively. These feedstuffs and heat treated soybeans will provide the substrate for microbial metabolism in an In Vitro artificial rumen to determine rate of energy and protein availability for maximum microbial protein synthesis. Also, in an effort to increase the amount of soybean meal protein escaping ruminal degradation, pelleting of soybean meal with lignosulfonate has been examined. Results indicate that soybean meal pelleted with 4% lignosulfonate reduced ammonia-nitrogen release by 55% in rumen fluid incubated for 6 hours. This suggests that pelleting of soybean meal with lignosulfonate may substantially reduce ruminal protein degradation and is currently being studied further.

                            Impacts
                            (N/A)

                            Publications