Evaluation of alternative growth promoter as modulating factors of broiler chickens microbiota in commercial farms
Crowded conditions of the intensive farming favored infection transmission and animal diseases. One of the main global questions regarding animal production is the use of antimicrobials as prophylactic additives on diet. There is a wide variety of alternative dietary additives to antibiotics, particularly the addition of tannins in animal diets began to be used to improve nutrition and control enteric diseases. We analyzed samples from a trial carried out on a commercial farm, evaluating both cecal and litter microbiota, by adding subtherapeutic doses of antibiotics (BAC) or tannins (TAN) to the diet, with the aim of characterizing the intestinal microbiota in response to the use of growth promoters, in commercial environments. The results obtained let us describe differential modulation trends using TAN or BAC as growth promoters. We observed an increase in the Firmicutes/Bacteroidetes ratio in TAN treatment, due to the increase in the relative abundance of Clostridiales order. This order has been related to improvements in the gut health of birds and better energy efficiency, suggesting that could be related to growth improvements. On the other hand, the analysis of the poultry litter microbiota allows us to find typical bacteria from the gastrointestinal tract of chickens and also pathogenic and environmental ones. This information becomes relevant considering that litter is reused in sheds, making the bacteria present in litter work as inoculum of the new birds in the next cycle, determining their microbial composition. In addition, the bacteria present in the litter could be spread in the environment when litter is used as organic fertilizer in agricultural production. Finally, the demands of both consumers and producers show the need for new production paradigms that meet their expectations in aspects related to health, animal welfare, environmental impact, and the performance of agricultural production.