Probiotics in Poultry Farming and their Effects on Gut Microbiota, Immunity and Productivity: A Review

Poultry farming in Brazil is one of the agricultural activities that is gradually evolving, making the country the third largest producer and exporter of chicken meat in the world. Antibiotic supplementation has traditionally been used to stabilize the intestinal microbiota, accelerate production, and prevent poultry diseases. However, due to the emergence and spread of resistant bacteria, viable alternatives to antibiotics, such as probiotics, have been sought. While existing studies have explored the benefits of probiotics in poultry, there is a lack of comprehensive reviews that systematically analyze their mechanisms of action, effects on gut microbiota, immunity, and overall productivity. This review aims to fill this gap by compiling and analyzing recent research on the use of probiotics in poultry farming, focusing on their role in enhancing nutrient utilization, improving gut health, and modulating immune responses. A total of 364 articles were reviewed, with 206 selected for detailed analysis. The findings demonstrate that probiotics promote metabolic processes of digestion and nutrient utilization, influence enzymatic activities, increase the absorptive surface of microvilli, and enable optimal nutrient use. This review provides a comprehensive understanding of how probiotics can be effectively integrated into poultry farming to improve productivity and health, offering insights for future research and practical applications in the industry.