Modulatory effects of medium chain fatty acids in poultry nutrition and health

摘要

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.