|Cheng, Heng Wei|
Submitted to: Poultry Science
Publication Type: Abstract Only
Publication Acceptance Date: 2/28/2010
Publication Date: 7/11/2010
Citation: Felver-Gant, J.N., Mack, L.A., Dennis, R.L., Cheng, H. 2010. Genetic Variations of Physiological Responses Following Heat Stress in Laying Hens [abstract]. Poultry Science. 89:T38(E-Suppl. 1). Interpretive Summary:
Technical Abstract: Heat stress (HS), also known as hyperthermia, is a major problem experienced by poultry during high-temperature conditions. The ability to manage the detrimental effects of HS can be attributed to many factors, including genetics. The objective of the present study was to determine the variation of effects that HS poses on the well-being of laying hens. Ninety 28-week-old White Leghorns of two strains were used; a line of individually-selected hens for high productivity and survivability, DeKalb XL (DXL), and a line of group-selected hens, kind gentle bird (KGB). Hens were randomly paired, housed by strain and assigned to hot (H) or control (C) treatments for 14 days (mean: C=24.3°C, H=32.6°C). Physiological measures were collected at day 8 and 14. Behavior data was collected at days 1, 2, 6, 9, and 13. Compared to controls, H-hens core temperature (CT) was significantly higher at day 8 and 14 (p<0.05). Heterophil:Lymphocyte ratios were significantly higher in H-hens at day 14 (p<0.05). H-hens had significantly reduced liver wt (LW) and spleen wt (SW) at day 8 and 14 (p<0.05) and body wt (BW) at day 14 (p<0.05). H-hens tended to have reduced BW at day 8 (p<0.10) and heart wt (HW) at day 14 (p<0.10). H-DXL had significantly reduced LW than H-KGB at day 8 (p<0.05). Behaviorally, H-hens opened their wings significantly more than C-hens (p<0.05). C-hens did not initiate thermal panting. H-KGB hens exhibited panting behavior significantly more than H-DXL (p<0.05). The data suggest that HS has detrimental effects on the physiology of laying hens. However, differences were observed in HS response due to the genetic basis of variation. These results provide evidence that will be valuable for determining interventions for laying hens under HS.