Dietary Effect of Negro Pepper (Xylopia aethiopica) Supplementation on the Gut Health of Hybrid African Catfish (Clarias gariepinus x Heterobranchus bidorsallis)

The dietary effects of Xylopia aethiopica supplementation on gut health in hybrid African catfish (Clarias gariepinus ♀ × Heterobranchus bidorsallis ♂) were evaluated. Five isonitrogenous diets containing graded levels of X. aethiopica (0, 0.5, 1.0, 1.5, and 2.0 %) were administered to assess changes in gut microbiota composition, digestive enzyme activities, and intestinal histology, to identify the optimal inclusion level for gut function. Supplementation with X. aethiopica significantly reduced the abundance of pathogenic bacteria, notably Salmonella spp., Staphylococcus aureus, and Escherichia coli, with the greatest reduction observed at a 1% inclusion rate. Microbial diversity increased at moderate supplementation (1.0%) but decreased at higher levels. Activities of digestive enzymes, including protease, amylase, and lipase, were significantly higher in fish receiving 1.0% and 1.5% supplementation, indicating improved digestive efficiency. Histological analysis revealed that supplementation with 1% preserved normal intestinal architecture, whereas higher inclusion levels (≥1.5%) induced mild mucosal erosion and inflammatory changes. These findings indicate that X. aethiopica supplementation, particularly at 1.0%, optimally supports a healthy gut microbiota, enhances digestive enzyme activity, and maintains intestinal integrity in hybrid African catfish. The results highlight the potential of X. aethiopica as a natural feed additive in aquaculture nutrition, providing an alternative to synthetic growth promoters and antibiotics. Appropriate inclusion can improve feed utilization, enhance growth performance, reduce disease risk, and promote more sustainable and productive aquaculture systems. Keywords: Additives, Intestinal microbiome, amylase, Fish, intestinal morphology, Aquaculture feed