OSU Researcher Giving Turkeys a Stronger Leg to Stand On

COLUMBUS, Ohio - A model developed to measure bone strength in poultry may help farmers choose breeds that meet market demand for meaty birds while eradicating bone deformities associated with rapid weight gain. Alfred Soboyejo, an Ohio State University agricultural engineering researcher, studied physical and biochemical factors associated with poultry breeding to determine what combinations increase tibia and femur bone strength in turkeys and broiler chickens. Genetic selection of poultry breeds to improve body weight increases weight gain without compensating for increased bone strength to support that weight. The result is leg bone deformities, such as "bowing" and "buckling" that cause lameness, broken bones and inflammations, and cost the poultry industry $32 million a year in production losses. Karl Nestor, an animal science researcher from Ohio Agricultural Research and Development Center in Wooster, OH, collaborated with Soboyejo on the project. Soboyejo found that specific poultry breeds play a role in increasing bone strength and believes that bone deformities could eventually be eliminated through genetic selection in much the same manner it has paved the way for bigger birds with good meat. "Species are very important. We can't select birds on body weight alone. We have to find ways to increase the body weight and breast muscle with correspondingly higher bone strength in the legs to promote good health of the bird," said Soboyejo. "By identifying poultry breeds that exhibit the best bone strength, we can then recommend to farmers which birds are best for the market." The project is the first of its kind to combine the principles of biomechanics and probabilistic structural mechanics with biology to identify and control physical and biochemical parameters as they relate to bone structure. Soboyejo, looking for a quantitative tool useful to farmers, developed new models for the quantification of bone strength and body weight gains in turkeys and broiler chickens, as they relate to physical and biochemical parameters. Some of these parameters of bones include elasticity of the cellular structural material of the bone, density and collagen content. Soboyejo found that certain chemical factors, such as collagen content of bone and the presence of pryridinoline and deoxypridinoline, also enhance overall bone strength. Collagen, a protein that largely makes up the organic layer of bone, combines with calcium salt crystals that form a cellular bone material with high mechanical properties of tensile and compressive strengths. Pyridinoline and deoxypridinoline are crosslinks of bone collagen used as markers to test bone diseases because they are released into the blood during bone degradation. Soboyejo suggested that a change in diet or addition of vitamins to a diet might enhance the effects of those chemical indicators to improve bone strength. Soboyejo believes that such indicators used to measure bone strength in poultry can also have practical applications in other scientific fields such as veterinary medicine and orthopedic medicine. "People suffering from osteoporosis, for example, could benefit from this type of work, because the factors that contribute to bone strength can be clearly identified and controlled," he said.