SUMMARY With the current bans and limitations on antibiotics as growth promoters, feed additives, such as prebiotics, probiotics, and organic acids are widely used to inhibit the effects of pathogenic microorganisms on poultry health. Recently, medium-chain fatty acids (MCFAs) have become a focus of attention due to their potentially favourable antimicrobial effects. Fatty acids with a chain length between six and 12 carbon atoms are regarded as MCFAs. Research results showed that MCFAs are effective against a wide range of enteric microorganisms. They act by reducing colonisation of enteric bacteria (by an average of 44%, 78%, 79% and 66% for Campylobacter spp., Clostridium spp., Salmonella spp. and Escherichia coli, respectively) in chicken intestines. Improved growth performance (by an average of 4% and 12% for body weight gain and feed conversion ratio, respectively) can be attributed to a healthier and more stable gut environment created by MCFAs. Moreover, dietary MCFAs may help to promote immune function, with reduced mortality reported of up to 20%. Trials have revealed that effective dosages include 2.9 g/kg caproic, 7.0 g/kg caprylic, 1.7 g/kg capric, 2.0 g/kg lauric, 2.5 g/kg monocaprin and 3.0 g/kg MCFAs in poultry diets. Studies indicated that MCFAs can reduce abdominal fat (by up to 30%) in broilers and reduce contaminated egg yolk and shells (up to 76% for Salmonella spp.), which is desired by consumers. Considering such benefits, MCFAs have the potential to be an alternative to antibiotic growth promoters in poultry nutrition and reduce the risk for antimicrobial resistance.

中文翻译：

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中链脂肪酸对家禽营养和健康的调节作用

总结 由于目前对抗生素作为生长促进剂的禁令和限制，饲料添加剂，如益生元、益生菌和有机酸被广泛用于抑制病原微生物对家禽健康的影响。最近，中链脂肪酸 (MCFA) 由于其潜在的有利抗菌作用而成为关注的焦点。链长在 6 到 12 个碳原子之间的脂肪酸被视为 MCFA。研究结果表明，MCFAs 对多种肠道微生物有效。它们的作用是减少肠道细菌的定植（弯曲杆菌属、梭菌属、沙门氏菌属和大肠杆菌分别平均减少 44%、78%、79% 和 66%）。改善的生长性能（体重增加和饲料转化率分别平均提高 4% 和 12%）可归因于 MCFA 创造的更健康、更稳定的肠道环境。此外，膳食中的 MCFA 可能有助于促进免疫功能，据报道死亡率降低高达 20%。试验表明，在家禽日粮中的有效剂量包括 2.9 g/kg 己酸、7.0 g/kg 辛酸、1.7 g/kg 癸酸、2.0 g/kg 月桂酸、2.5 g/kg 单癸酸和 3.0 g/kg MCFA。研究表明，MCFA 可以减少肉鸡的腹部脂肪（最多 30%），并减少受污染的蛋黄和蛋壳（沙门氏菌最多 76%），这是消费者所期望的。考虑到这些好处，中链脂肪酸有可能成为家禽营养中抗生素生长促进剂的替代品，并降低抗微生物药物耐药性的风险。