Betaine: A Potential Nutritional Metabolite in the Poultry Industry

SIMPLE SUMMARY: The effects of antibiotics as alternative feed additives on the health of poultry have gained promising results. Betaine has been extensively used in the poultry industry as a potential metabolite. This review article focuses on the interaction between betaine and other elements, such as methionine, choline, and creatine. In addition, poultry carcass traits and performance, as well as its osmoregulatory, anticoccidial, immune-modulatory, and heat-stress alleviation activities, were discussed with regard to the effects of dietary supplementation of betaine. Due to the different advantages of using betaine, it has been suggested to be a promising feed additive to the poultry diet. More research is needed to explain how betaine exerts its action in the body. ABSTRACT: Poultry industry has been recognized as a fast-developing sector aiming to produce low-cost and high-nutrient foods for human consumption. This review article aimed to focus on the significant roles of dietary betaine supplementation in the poultry industry. In this respect, different effects of betaine on performance and carcass traits, as well as its osmoregulatory, anticoccidial, immune-modulatory, and heat-stress alleviation activities, were discussed. Different concentrations of betaine supplementation can improve the feed conversion ratio, final body weight, breast muscle yield, egg production ratio, and reduce body fat contents in broiler chicken, turkey, duck, geese, and quail diets. Betaine supplemented with methyl groups can eliminate the need to have some methyl-group donors, including choline and methionine, therefore having positive effects on feed conversion ratio in poultry diets. The osmolytic character of betaine can alleviate heat stress and have a positive impact on tonic immobility, which consequently reduces stress in poultry. By inhibiting distinct developmental stages of Eimeria species, betaine reduces the damaging effects of coccidiosis on broiler chickens and improves intestinal structure and function. The immunological, cardiovascular, neurological, renal, and hepatic metabolic systems benefit from betaine’s osmo-protective properties. Therefore, betaine has the potential to be considered as an alternative to feed additives and enhances the health status and productive performance of poultry.