Effects of xylanase, protease, and xylo-oligosaccharides on growth performance, nutrient utilization, short chain fatty acids, and microbiota in -challenged broiler chickens fed high fiber diet.

A 21-d experiment was conducted to study the effect of xylanase, protease, and xylo-oligosaccharides on growth performance, nutrient utilization, gene expression of nutrient transporters, cecal short-chain fatty acids (SCFA), and cecal microbiota profile of broilers challenged with mixed spp. The study utilized 392 zero-d-old male broiler chicks allocated to 8 treatments in a 4 × 2 factorial arrangement, as follows: corn-soybean meal diet with no enzyme (Con); Con plus xylanase alone (XYL); Con plus xylanase combined with protease (XYL + PRO); or Con plus xylo-oligosaccharides (XOS); with or without challenge. Diets were based on a high-fiber (100 g/kg soluble fibers and 14 g/kg insoluble fibers) basal diet. At d 15, birds in challenged treatment were gavaged with a solution containing , , and oocysts. At d 21, birds were sampled. depressed ( < 0.01) growth performance and nutrient utilization, whereas supplementation had no effect. There were significant  × supplementation interactions for the sugar transporters ( = 0.02), ( = 0.01), ( < 0.01), and peptide transporter ( < 0.01) in jejunal mucosa. challenge increased the expression of ( < 0.01) and ( = 0.04) but decreased ( = 0.03) expression in the cecal tonsil.  × supplementation interactions for cecal acetate, butyrate, and total SCFA showed that concentrations increased or tended to be greater in the supplemented treatments, but only in non-challenged birds. Birds challenged with spp. had higher concentrations of isobutyrate ( < 0.01), isovalerate ( < 0.01), and valerate ( = 0.02) in cecal content. challenge significantly ( < 0.01) decreased the microbial richness and diversity, and increased ( < 0.01) the proportion of , , and . In conclusion, infection depressed growth performance, nutrient utilization with regulating nutrient transporters. Furthermore, challenge shifted the microbial profile and reduced microbial richness and diversity. On the other hand, enzyme supplementation showed limited benefits, which included increased concentrations of SCFA.