|Kannan, L - UNIVERSITY OF ARKANSAS|
|Pillai, P - UNIVERSITY OF ARKANSAS|
|Horst, R - UNIVERSITY OF ARKANSAS|
|Emmert, J - UNIVERSITY OF ARKANSAS|
Submitted to: Research in Veterinary Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 13, 2006
Publication Date: July 1, 2007
Citation: Rath, N.C., Kannan, L., Pillai, P.B., Huff, W.E., Huff, G.R., Horst, R.L., Emmert, J.L. 2007. Evaluation of the efficacy of vitamin D3 or its metabolites on thiram-induced tibial dyschondroplasia in chickens. Research in Veterinary Science. 83(2):244-250. Interpretive Summary: Meat-type poultry suffer from a 'leg problem’ called ‘tibial dyschondroplasia’ where parts of growing end of some leg bone fail to form bone. Vitamin D deficiency has been thought to cause this defect. Using an experimental model to induce this problem our studies show that vitamin D deficiency may not be the factor for the occurrence of this disease nor the supplemental fortification of diets with any vitamin D metabolites would protect chickens against this leg problem.
Technical Abstract: Two trials were conducted to determine if thiram-induced tibial dyschondroplasia (TD) in chickens was linked to a vitamin D deficiency and calcium homeostasis dysregulation, and whether feeding vitamin D fortified diets may prevent it. Day-old chickens were given grower diets containing different vitamin D products throughout the experiment until necropsy on day 16. Half of the birds in each feed group received thiram at levels of 100 ppm (trial 1) or 50 ppm (trial 2) between days 7-9 to induce TD. The birds were weighed, bled, and euthanized to determine TD incidences and severity by examining the growth plates. Tibial bones were used to measure biomechanical strength and ash content. Blood concentrations of 25-hydroxyvitamin D, Ca, P, alkaline phosphatase, and creatine kinase were measured in serum that showed no differences between different groups. Thiram reduced body weight and induced TD regardless of any vitamin D treatment to the same extent as untreated birds.