|Dozier iii, William|
Submitted to: Poultry Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 4/15/2006
Publication Date: 5/15/2006
Citation: Thaxton, J.P., Dozier III, W.A., Branton, S.L., Morgan, G.W., Miles, D.M., Roush, W.B., Lott, B.D., Vizzier-Thaxton, Y. 2006. Stocking density and physiological adaptive responses of broilers. Poultry Science. 85:819-824. Interpretive Summary: Animal welfare has generated concerns from both domestic and global market sectors in marketing meat products of broiler chickens. Stocking density in growout has been regarded as a concern to food retailers and wholesalers. High stocking density has been reported to adversely affect the well being of the broiler. This study evaluated physiological indicators of stress as influenced by stocking density. Three trials were conducted that evaluated stocking density ranging from 25 to 55 kg BW/m2. Results indicated that increasing stocking density from 25 to 55 kg BW/m2 of floor space did not affect indicators of stress such as corticosterone, glucose, cholesterol, heterophil:lymphocyte ratio, and total nitrites. These results provide new knowledge that stocking density indicative of commercial practice does not induce stress in broilers grown to heavy weights.
Technical Abstract: Three trials were conducted to assess the effects of stocking density on physiological adaptive responses of broilers. Male broilers were reared in floor pens under conditions assimilating those used commercially in the United States. Accepted indicators of adaptation to a stressor were measured on d 49 including plasma concentrations of corticosterone (CS), glucose (GLU), cholesterol (CHOL), and total nitrites, as an indicator of nitric oxide, as well as heterophil:lymphocyte (H:L) ratio. In Trial 1, calculated stocking densities were 20, 25, 30, 35, 40, 45, 50, and 55 kg BW/m² and in Trials 2 and 3 stocking densities were 30, 35, 40 and 45 kgBW/m². Stocking densities were calculated based on a final BW of 3.3kg. Linear trend analyses were used to assess the role of stocking density on each of the physiological parameters. Results indicate that stocking density did not cause physiological adaptive changes indicative of stress.