Author
SHINI, S - UNIV OF QUEENSLAND | |
SHINI, A - UNIV OF QUEENSLAND | |
Huff, Geraldine | |
KAISER, P - INST. FOR ANIMAL HLTH, UK | |
BRYDEN, W - UNIV OF QUEENSLAND |
Submitted to: World Poultry Congress Proceedings
Publication Type: Proceedings Publication Acceptance Date: 6/30/2008 Publication Date: 6/30/2008 Citation: Shini, S., Shini, A., Huff, G.R., Kaiser, P., Bryden, W.L. 2008. Effects of repeated oral corticosterone administration on performance and stress parameters of laying hens. In: Proceedings of the 23rd World Poultry Congress, June 30 - July 4, 2008, Queensland, Brisbane, Australia. 2008 CDROM. Interpretive Summary: The effects of repeated stress during rearing on performance and physiology of laying hens was studied using a compound that simulates stress. 240 Hisex laying hens were reared in environmentally controlled battery cages. At 7, 11, and 15 weeks of age they were exposed for 1 week to the compound in drinking water or untreated water. At each treatment point (1 h, 3 h, 24 h, and 1 wk post-treatments) tests were conducted to determine the effects of the compound. Body weight and egg production were measured throughout the study. Birds treated with the compound had decreased body weight and higher levels of the compound in their blood. A ratio of different types of white blood cells (called the heterophil to lymphocyte ratio, H/L) is used to measure stress in birds. When delivery of the compound was interrupted, its levels in the blood and the H/L ratio were reduced and both were unchanged at 35 weeks of age. Exposing birds to repeated and long-term administration of the compound caused significant changes in plasma glucose, cholesterol, and triglyceride levels. The compound delayed the laying cycle and decreased production at peak of lay. These results demonstrate that oral administration of this compound affects hen physiology, decreases performance, and may model the effects of production stressors. Technical Abstract: The effects of repeated stress during rearing on performance and physiology of laying hens was studied using a corticosterone (Cort) model. 240 Hisex laying hens were reared in environmentally controlled battery cages. At 7, 11, and 15 wk of age they were exposed for 1 wk to the following treatments in drinking water: Cort dissolved in ethanol, ethanol, or untreated water. At each treatment point (1 h, 3 h, 24 h, and 1 wk post-treatments) endocrine, metabolic and haematological tests were conducted. Body weight and egg production were measured throughout the study. Cort treated birds had decreased body weight compared to both controls, which was associated with increases in both plasma Cort level and heterophil to lymphocyte ratio (H/L). When Cort delivery was interrupted, plasma Cort and H/L were reduced and both were unchanged at 35 wks of age. Exposing birds to repeated and long-term Cort caused significant changes in plasma glucose, cholesterol, and triglyceride levels. Cort delayed the laying cycle and decreased production at peak of lay. These results demonstrate that oral Cort administration affects hen physiology, decreases performance, and may model the effects of production stressors. |