Author:

Keywords:

Science & Technology, Life Sciences & Biomedicine, Agriculture, Dairy & Animal Science, Agriculture, acute heat stress, brain-gut neuropeptides, broiler chicken, feed intake, CORTICOTROPIN-RELEASING-FACTOR, REGULATING FOOD-INTAKE, ENERGY-BALANCE, BODY-WEIGHT, FEED-INTAKE, GHRELIN, CORTICOSTERONE, CHOLECYSTOKININ, PERFORMANCE, RESPONSES, Animals, Chickens, Gastrointestinal Tract, Gene Expression Regulation, Hormones, Hot Temperature, Hypothalamus, Male, Neuropeptides, Stress, Physiological, Time Factors, 06 Biological Sciences, 07 Agricultural and Veterinary Sciences, Dairy & Animal Science, 30 Agricultural, veterinary and food sciences, 31 Biological sciences

Abstract:

Heat stress-induced reduction in feed intake is an annoyance of the poultry industry. Feed intake is regulated by complex mechanisms in which brain-gut neuropeptides are involved, but the changes in such neuropeptides in broiler chickens during heat exposure remain unclear. In this study, we investigated the effects of acute heat stress (35°C, 6 h, and 65% relative humidity) on the gene expression of appetite-regulating peptides in the hypothalamus and gastrointestinal tract of broiler chickens at 42 d of age. The hypothalamic mRNA levels of neuropeptide Y, agouti-related peptide, pro-opiomelanocortin, cocaine- and amphetamine-regulated transcript, corticotropin-releasing hormone, melanocortin 4 receptor, melanin-concentrating hormone, prepro-orexin, cholecystokinin (CCK), and ghrelin did not significantly change (P>0.05) in the heat-exposed broiler chickens. However, the mRNA levels of ghrelin in the glandular stomach, duodenum, and jejunum significantly increased and the mRNA level of CCK in the duodenum significantly decreased. The results indicate that acute heat stress had no effect on the gene expression of central appetite-regulating peptides under current experimental conditions; however, some gastrointestinal tract peptides (e.g., ghrelin and CCK) might play a role in the regulation of appetite in acute heat-exposed broiler chickens. Furthermore, ghrelin in the glandular stomach, duodenum, and jejunum might be the main regulative target of acute heat stress induced anorexia.