Effects of dietary supplementation of endo-(1,4)-β-xylanase in plant-based diets on growth performance, hindgut microbial diversity, and blood chemistry in large on-growing African catfish (Clarias gariepinus)

The study aimed to investigate the impacts of dietary supplementation of endo-(1,4)-β-xylanase in high plant-ingredient diets in on-growing African catfish (Clarias gariepinus). A high plant-ingredient basal diet was supplemented with exogenous xylanase at 0 (Control diet), 100, 150, and 200 ppm, and fed to on-growing (initial weight ca 500 g) fish for a duration of 91 days. Growth parameters, fillet proximate composition, hindgut microbial diversity, hindgut short-chain fatty acid concentration, and blood chemistry parameters were monitored. There were no effects on growth parameters, fillet proximate composition, hindgut short-chain fatty acid concentration, and blood chemistry parameters. Dietary xylanase supplementation caused a significant shift in hindgut microbial diversity, where the 200 ppm treatment showed significantly lower Shannon diversity (2.15 ± 0.13) than the control (2.78 ± 0.21). The significantly lower microbial diversity indicates that enzyme supplementation selectively benefitted certain microbial populations in the hindgut, presumably through the release of prebiotic compounds during non-starch polysaccharide hydrolysis. It is concluded that dietary xylanase supplementation can significantly impact hindgut microbial communities in on-growing African catfish, and it is recommended that future work investigate whether dietary xylanase supplementation can benefit aquaculture production performance in younger fish.