Bile acids are used for better emulsification, digestion and absorption of dietary fat in chicken, especially in early life. Similarly, exogenous lipases have also been used for the improvement of physiological limitation of the chicken digestive system. Owing to potential of both bile acids and lipases, their use has been increased in recent years, for better emulsification of dietary fat and improvement of growth performance in broilers. In the past, pancreatic lipases were used for supplementation, but recently, microbial lipase is getting attention in poultry industry as a hydrolysis catalyst. Bile acids strengthen the defence mechanism of body against bacterial endotoxins and also play a key role in lipid regulation and sugar metabolism as signaling molecules. It has been demonstrated that bile acids and lipases may improve feed efficiency by enhancing digestive enzyme activity and ultimately leading to better fat digestion and absorption. Wide supplemental range of bile acids (0.004% to 0.25%) and lipases (0.01% to 0.1%) have been used in broiler diets for improvement of fat digestibility and their performance. Combinations of different bile acids have shown more potential to improve feed efficiency (by 7.14%) even at low (0.008%) levels as compared to any individual bile acid. Lipases at a lower level of 0.03% have exhibited more promising potential to improve fat digestibility and feed efficiency. However, contradicting results have been published in literature, which needs further investigations to elucidate various nutritional aspects of bile acids and lipase supplementation in broiler diet. This review focuses on providing insight on the mechanism of action and potential application of bile acids and lipases in broiler diets. Moreover, future implications of these additives in poultry nutrition for enhancing nutrient utilization and absorption are also discussed.

中文翻译：

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肉鸡日粮中添加胆汁酸和脂肪酶可提高养分利用率和生产性能：潜在影响和未来影响

胆汁酸用于更好地乳化，消化和吸收鸡肉中的膳食脂肪，尤其是在早期生活中。类似地，外源脂肪酶也已用于改善鸡消化系统的生理限制。由于胆汁酸和脂肪酶的潜力，近年来它们的使用已经增加，以更好地乳化膳食脂肪并改善肉鸡的生长性能。过去，胰腺脂肪酶被用作补充，但近来，微生物脂肪酶作为水解催化剂在家禽业受到关注。胆汁酸可增强机体抵抗细菌内毒素的防御机制，并在脂质调节和糖代谢中作为信号分子发挥关键作用。已经证明胆汁酸和脂肪酶可以通过增强消化酶的活性并最终导致更好的脂肪消化和吸收来提高饲料效率。肉鸡日粮中添加了广泛的胆汁酸（0.004％至0.25％）和脂肪酶（0.01％至0.1％）补充剂，以改善脂肪的消化率及其性能。与任何单独的胆汁酸相比，即使在低水平（0.008％）的情况下，不同胆汁酸的组合也显示出更大的潜力来提高饲料效率（提高7.14％）。脂肪酶的含量较低，为0.03％，具有改善脂肪消化率和饲料效率的潜力。然而，矛盾的结果已经在文献中发表，需要进一步研究以阐明肉鸡日粮中胆汁酸和脂肪酶补充的各种营养方面。这篇综述着重于提供对肉鸡日粮中胆汁酸和脂肪酶的作用机理和潜在应用的见解。此外，还讨论了家禽营养中这些添加剂对提高营养物利用和吸收的未来意义。