Comparison study of protective effects of porcine bile acids and sheep bile acids against heat stress in chickens

Abstract BACKGROUND Heat stress (HS) is known to exert negative effects on the poultry and breeding industry, resulting in severe economic losses. Bile acids (BAs), an important component of bile, play a crucial role in improving the production performance of livestock and poultry, alleviating stress injury, and ensuring the health of livestock and poultry. At present, porcine BAs are widely used because of their therapeutic effects on HS; however, it remains unclear whether the same effects are exerted by sheep BAs, which are different from porcine BAs and have different compositions. In this study, we compared the anti‐HS effects of porcine BAs and sheep BAs in the diet by establishing an HS model of chicks and investigating the chicken performance, HS‐related genes' expression, oxidative stress markers, jejunal histoarchitecture, inflammatory cytokines' expression, jejunal secreted immunoglobulin A concentration, and cecal bacterial flora. RESULTS The results showed that the addition of sheep BAs to the diet increased the average daily weight gain and the feed conversion ratio of chicks. Under HS, sheep BAs were more effective than porcine BAs in improving the activities of lactate dehydrogenase and glutamic pyruvic transaminase in serum and the content/activity of malondialdehyde, superoxide dismutase, and reduced glutathione in serum and tissue, in reducing the messenger RNA (mRNA) expression of heat shock proteins (HSP60, HSP70, and HSP90) in the liver and jejunum, and in improving the histological structure and the expression of tight junction proteins (occludin and zonula occludens‐1) and enriching intestinal bacterial flora. However, porcine BAs were significantly inferior to sheep BAs in reducing the mRNA expression of inflammatory factors (interleukin‐6, interleukin‐1 β , and tumor necrosis factor‐ α ). CONCLUSION The effect of sheep BAs was more significant than porcine BAs was in alleviating HS injury in chicks, suggesting that sheep BAs have great potential as new feed nutrition and health additive to improve poultry production performance and prevent HS. © 2023 Society of Chemical Industry.