Giving Chickens a Firmer Leg to Stand On

Some leg ailments in broiler chickens are related to excessive dead cells in the inner, larger bone just below the knee--called the tibia--which prevents bone tissue from forming, Agricultural Research Service scientists report.

Today's broiler chickens are bred for fast growth; the growth rate for modern-day broilers is almost double that of 30 years ago. The bones do not always have enough time to mature and grow properly.

This has led to problems of tibial dyschondroplasia (TD), a major metabolic disorder that causes bone problems in chickens and turkeys, according to ARS poultry physiologist Narayan Rath in Fayetteville, Ark. TD impedes bone from replacing cartilage, causing the tibia to be soft, fragile and prone to bone deformities and breakage.

Bone strength is related to bone density and mineral content. Chemical bonding, called "cross links," ties together collagen fibers that form the major bone structure, increasing collagen strength and eventually bone strength.

Rath is examining the collagen cross links from birds at different ages to learn more about bone strength. The goal: to see if cross links can be enhanced to increase bone strength. The researchers hope to establish methods that will reduce bone-related problems that cost the poultry industry millions of dollars in losses each year.

More information on this research appears in the May issue of Agricultural Research magazine. The story is also on the World Wide Web at:

http://www.ars.usda.gov/is/AR/archive/may98/firm0598.htm

An in-depth study on Rath's research on cell death and tibial dsyschondroplasia appears in the January-March 1998 issue of Avian Diseases 42:72-79.

Scientific contact: Narayan Rath, ARS Poultry Production and Product Safety Research Unit, Fayetteville, Ark., phone (501) 575-6189, fax (501) 575-4202, nrath@comp.uark.edu.