Source: Hooge Consulting Service, Inc. submitted to
DIETARY L-THYROXINE TO INDUCE MOLT WITHOUT FEED WITHDRAWAL IN LAYING CHICKEN, BROILER BREEDER, AND TURKEY BREEDER HENS TO EXTEND PRODUCTION
 
PROJECT DIRECTOR: Hooge, D. M.
 
PERFORMING ORGANIZATION
(N/A)
Hooge Consulting Service, Inc.
Eagle Mountain,UT 84043
 
NON TECHNICAL SUMMARY: Molting (reproductive rejuvenation) of poultry to extend table or fertile egg production is a well accepted commercial practice in the U.S. However, the conventional method of ~10-day feed withdrawal to induce molt is increasingly viewed as unacceptable by McDonald's, Wendy's, AVMA, and the egg consuming public. The use of dietary L-thyroxine (T4; the natural molting hormone) for poultry can provide an effective commercial method of inducing molting while providing full access to treated feed and water. These studies will gather further information on the feasibility of the concept and how it should be carried out in chickens and turkeys to extend egg production, improve profitability, and assure animal welfare.
 
OBJECTIVES: Live poultry will be used to conduct feeding trials with L-thyroxine from supplemental dietary levothyroxine (L-thyroxine) and/or thyroactive iodinated casein to compare this method with conventional 10-day feed withdrawal molting (reproductive rejuvenation) to extend table or fertile egg production. Caged laying hens, broiler breeder hens, and turkey breeder hens will be evaluated in separate trials, but information will be obtained from results about species similarities and differences. Other goals will be to determine the iodine content of eggs collected during the molting procedures, to obtain blood samples for counting heterophil / leukocyte ratio as an indicator of level of stress, to measure body weight loss and extent of regression of ovaries and oviduct, and in some studies to determine subsequent live performance of hens following the molting process.
 
APPROACH: Small scale studies will be conducted at 4 locations in AR (broiler breeder hens), NC (turkey breeder hens, 2 sites), and VA (caged laying hens) to further assess the feasibility of the concept of using L- thyroxine in the feed of poultry to induce molting (cessation of egg production, feather loss, body weight reduction, regression of ovaries and oviduct) while allowing full access to treated feed and water. The conventional 10-day feed withdrawal method will be used as a control procedure. The FDA allows investigational products (test articles) such as L-thyroxine and thyroactive iodinated casein to be shipped interstate for study purposes and for trials to be conducted with live poultry as long as accurate, complete, and detailed records are kept (Title 21, CFR 511.1a). However, no eggs or poultry meat can go into the human food chain and all leftover birds and feed must be disposed of by incineration or landfill. These studies will help develop a patent pending commercial method of molting to extend egg production.
 
CRIS NUMBER: 0203122 SUBFILE: CRIS
PROJECT NUMBER: UTAK-2005-00125 SPONSOR AGENCY: NIFA
PROJECT TYPE: SMALL BUSINESS GRANT PROJECT STATUS: TERMINATED MULTI-STATE PROJECT NUMBER: (N/A)
START DATE: Jun 1, 2005 TERMINATION DATE: Jan 31, 2006

GRANT PROGRAM: SMALL BUSINESS AND INDUSTRY GRANTS
GRANT PROGRAM AREA: Small Business

CLASSIFICATION
Knowledge Area (KA)Subject (S)Science (F)Objective (G)Percent
315321010104.250%
315323010104.250%

CLASSIFICATION HEADINGS
KA315 - Animal Welfare/Well-Being and Protection
S3210 - Egg-type chicken, live animal
S3230 - Turkey, live animal
F1010 - Nutrition and metabolism
G4.2 - Reduce Number and Severity of Pest and Disease Outbreaks


RESEARCH EFFORT CATEGORIES
BASIC (N/A)%
APPLIED 100%
DEVELOPMENTAL (N/A)%

KEYWORDS: iodine; poultry; egg production; egg shell quality; diet; animal nutrition; thyroxine; molting; forced molting; layers; broilers; hens; turkeys; poultry production; feed intake; casein; cages; leukocytes; granulocytes; ovaries; oviducts; reproduction; performance evaluation

PROGRESS: Jun 1, 2005 TO Jan 31, 2006
Phase I grant funds were used to conduct 5 live poultry trials to further prove the concept and explore commercial feasibility of elevating blood thyroxine level by dietary supplementation with a thyroxine source to induce cessation of egg production ("molting") to extend egg production (after a rest period and photostimulation). A caged laying hen trial at Cal Poly, San Luis Obispo, demonstrated that either L-thyroxine (98%) or thyroactive iodinated casein (1% thyroxine), each contributing 40 ppm thyroxine, were effective for inducing cessation of egg production similarly (although slightly less quickly) than conventional 10-day feed withdrawal. Egg production was re-started and taken up to peak without any problems. A broiler breeder trial at University of Arkansas indicated that broiler breeders responded similarly to caged laying hens except for taken slightly longer to reach 0% egg production with L-thyroxine or iodinated casein. Male broiler breeders suffered excessive mortality due to elevated thyroxine apparently due to increased blood pressure and body heat. Thyroactive iodinated protein supplying 40 ppm thyroxine was about 81% as effective as L-thyroxine supplying 40 ppm thyroxine for regressing the ovary apparently due to some inefficiency in digestion and absorption of thyroxine from the casein source. Two short-term turkey breeder hen molting trials at Diamond K Research, Inc., Marshville, NC showed that L-thyroxine, iodinated casein, or defatted or full-fat porcine thyroid products reduced feed intake, and porcine thyroid powder (defatted) decreased ovary and oviduct weights similar to feed and water withdrawal treatment in one trial. In the second trial ovary and oviduct weights were decreased by feed and water withdrawal or porcine thyroid products. Thyroxine products usually did not affect egg weight or shell thickness in caged layers or turkey hens. A commercial type trial at Talley Farms in NC showed that iodinated casein (40 ppm thyroxine in feed) reduced feed intake to 0.14 lb/hen/day compared to 0.50 lb/hen/day. The number of pips and late dead poults in the hatchery were increased due to dietary iodiated casein. It was concluded that iodinated casein would be the most economical thyroxine source as a feed additive. Regular feeds and lighting (e.g., 16 hours/day) should be used to provide adequate calcium for shell formation and maximize intake of treated feed. Thyroxine products tended to increase blood heterophil:lymphocyte ratios similar to feed withdrawal molting treatment when comparing against the ratio in control fed broiler breeder hens. Phase II will emphasize FDA-type trials with caged layers primarily, but also some trials with broiler breeder and turkey breeder hen molting.

IMPACT: 2005-06-01 TO 2006-01-31 The Phase I research clearly demonstrated that supplementing diets of adult female caged laying hens, broiler breeders, or turkey breeders could be used to cause cessation of egg production for a rest period and subsequent extension of egg production. There was some increase in iodine content of eggs. Phase II grant research will emphasize caged laying hen molting using FDA-type protocols in order to prepare a dossier for submitting a performance claim of "cessation of egg production" for dietary thyroactive iodinated casein to FDA. A pharmaceutical company (ECO Animal Health, Ltd, London, UK) has signed a commitment agreement to provide supplemental and follow-on funding to help commercialize the thyroxine molting technology.

PUBLICATION INFORMATION: 2005-06-01 TO 2006-01-31
Kuenzel, W. J., R. F. Wideman, M. Chapman, C. Golden, and D. M. Hooge. 2005. A practical method for induced moulting of caged layers that combines full access to feed and water, dietary thyroactive protein, and short day length. World's Poult. Sci. J. 61(4):599-624.

PROJECT CONTACT INFORMATION
NAME: Hooge, D. M.
PHONE: 801-766-1234
FAX: 801-768-2345