|Dozier Iii, William|
Submitted to: Southern Poultry Science Society Meeting Abstracts
Publication Type: Proceedings
Publication Acceptance Date: 10/30/2004
Publication Date: 1/15/2005
Citation: Virden, W.S., Zumwalt, C.D., Thaxton, J.P., Corzo, A., Dozier III, W.A., Kidd, M.T. 2005. Comparison of two models for induction of controlled stress in broilers. Southern Poultry Science Society Meeting. Abstract 215. p. 51.
Technical Abstract: Prolonged stress in broilers results in the release of the stress hormone corticosterone (CS). Elevated levels of CS in the blood cause a severe decrease in meat production as a result of CS-induced gluconeogenesis. Research has demonstrated that controlled stress can be induced in broilers through continuous administration of either CS or adrenocorticotropic hormone (ACTH). An experiment was conducted to compare two methods of eliciting a controlled stress response in broilers. Two hundred-forty Ross X Ross 508 male broilers were randomly placed into 20 pens (12 birds/pen). All broilers received common starter diets from d 1 to 20. From d 21 to 35, stress treatments were administered. Treatments consisted of 1) control (no ACTH); 2) 4 IU of ACTH/kg BW injected i.m. for 7 d; 3) 8 IU of ACTH/kg BW injected i.m. for 7 d; or 4) 15 mg CS/kg of diet suspended in soybean oil for 14 d. On d 35, chicks receiving treatment 4 had lower BW (P < 0.01) than all other treatments. Chicks given either ACTH injection treatment had lower (P < 0.05) BW than that of control. Broilers receiving treatment 4 also displayed higher (P < 0.01) feed conversion ratio over chicks receiving all other treatments, whereas chicks receiving ACTH injections did not differ from control. Heterophil to lymphocyte ratio was higher (P < 0.01) in broilers receiving treatment 4 than in all other treatments. Chicks receiving treatment 3 had higher (P < 0.01) heterophil to lymphocyte ratio than chicks receiving treatment 2 or control. Cumulative feed intake and percentage mortality did not differ among treatments. Based on this research, feeding CS appears to be a more efficient method for eliciting a controlled stress response in broilers than ACTH injection.