Impact of Dietary Sodium Butyrate and Salinomycin on Performance and Intestinal Microbiota in a Broiler Gut Leakage Model

SIMPLE SUMMARY: Imbalanced microbiota related to intestinal leakage is an emerging health problem in commercial broilers associated with partial loss of gut function and reduction in growth performance. Salinomycin is an ionophore coccidiostat with antibiotic effect, which is used as additive in broiler diets to control enteric diseases and improve performance. Due to the growing concern of the development of bacterial antibiotic resistance, ionophores are expected to be banned, within the EU, as feed additives in the near future. Butyrate with multiple beneficial effects on growth performance and pathogen control in broilers has been introduced as a promising alternative. In this study, the ability of a coated butyrate product to alleviate intestinal imbalance was compared to that of salinomycin after enteric challenge. Compared to butyrate and non-supplemented control, salinomycin increased potentially beneficial Ruminococcaceae and reduced potentially pathogenic Enterobacteriaceae, and counts of Lactobacillus salivarius and Clostridium perfringens. Further, salinomycin improved broiler performance. Dietary inclusion of coated butyrate had only limited effects on the composition of the broiler microbiota. Whether improved growth and feed utilization in the salinomycin-supplemented animals can be explained by suppression of C. perfringens and L. salivarius and enrichment of butyrate- and lactic acid-producing bacteria (Ruminococcaceae and Lactobacillaceae) needs further verification. ABSTRACT: Unfavorable alterations of the commensal gut microbiota and dysbacteriosis is a major health problem in the poultry industry. Understanding how dietary intervention alters the microbial ecology of broiler chickens is important for prevention strategies. A trial was conducted with 672 Ross 308 day-old male broilers fed a basic diet (no additives, control) or the basic diet supplemented with 500 mg/kg encapsulated butyrate or 68 mg/kg salinomycin. Enteric challenge was induced by inclusion of 50 g/kg rye in a grower diet and oral gavage of a 10 times overdose of a vaccine against coccidiosis. Compared to control and butyrate-supplemented birds, salinomycin supplementation alleviated growth depression. Compared to butyrate and non-supplemented control, salinomycin increased potentially beneficial Ruminococcaceae and reduced potentially pathogenic Enterobacteriaceae and counts of Lactobacillus salivarius and Clostridium perfringens. Further, salinomycin supplementation was accompanied by a pH decrease and succinic acid increase in ceca, while coated butyrate (0.5 g/kg) showed no or limited effects. Salinomycin alleviated growth depression and maintained intestinal homeostasis in the challenged broilers, while butyrate in the tested concentration showed limited effects. Thus, further investigations are required to identify optimal dietary inclusion rates for butyrate used as alternative to ionophore coccidiostats in broiler production.