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)

ABSTRACT

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.

KEYWORDS:

• Arabinoxylan-oligosaccharides
• exogenous enzymes
• gut bacteria
• non-starch polysaccharides
• short-chain fatty acids

Acknowledgments

The financial assistance of the National Research Foundation (NRF) toward this research is hereby acknowledged, under the Research and Technology Fund project number 98614. Opinions expressed and conclusions arrived at, are those of the author and are not necessarily to be attributed to the NRF. The authors would further like to extend their gratitude to Nutrex nv for supplying the enzyme used during the trials.

Data availability statement

Data are available in the thesis of the first author, titled “The effects of xylanase and arabinoxylan oligosaccharides on the growth performance, nonspecific immunity, hindgut microbial diversity and hindgut short-chain fatty acid production of African catfish, Clarias gariepinus,” which is published online by Stellenbosch University, https://scholar.sun.ac.za/handle/10019.1/105842.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the National Research Foundation [98614].