Chicken Hepatic Response to Chronic Heat Stress Using Integrated Transcriptome and Metabolome Analysis

The liver plays a central role in metabolism and is important in maintaining homeostasis throughout the body. This study integrated transcriptomic and metabolomic data to understand how the liver responds under chronic heat stress. Chickens from a rapidly growing broiler line were heat stressed for 8 hours per day for one week and liver samples were collected at 28 days post hatch. Transcriptome analysis reveals changes in genes responsible for cell cycle regulation, DNA replication, and DNA repair along with immune function. Integrating the metabolome and transcriptome data highlighted multiple pathways affected by heat stress including glucose, amino acid, and lipid metabolism along with glutathione production and beta- oxidation. Overall design: Ross 708 broiler chickens were raised from day of hatch to day 28, on the University of Delaware farm. Birds were placed into two separate houses, one thermoneutral house and one experimental (heat stress) house. Both houses were kept at 23 hours of light and 1 hour of dark and birds were placed on litter and given feed (meeting all NRC requirements) and water with ad libitum access. Both houses were kept at 35 degrees celsius for the first week and the temperature was decreased 5 degrees celsius each week until 25 degrees celsius. The thermoneutral hosue was maintained at 25 degrees celsius for the remainder of the study. Starting on day 21, the experimental house began a cyclical heat stress scheme with 8 hours per day of increased temperatures (35 - 37 degrees celsius) through completion of the trial at day 28 where necropsies were performed and tissue samples collected.

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Jastrebski SF, Lamont SJ, Schmidt CJ