Dietary Saccharomyces cerevisiae enhanced growth performance, short-chain fatty acids, and reduced the susceptibility of African catfish, Clarias gariepinus to Aeromonas hydrophila infection.

Rise in antibiotic-resistant bacteria strains in aquaculture demands for an ecofriendly alternative, hence this study evaluates the impact of dietary Saccharomyces cerevisiae, sourced locally from corn slurry (LYSc) and foreign/internationally from Lesaffre’s SAF-Instant yeast (FYSc), on the growth, antioxidant, immune responses, and susceptibility of African catfish, Clarias gariepinus to Aeromonas hydrophila infection. Three diets (400 g crude protein/kg diet); control (diet without FYSc and LYSc), 6 g FYSc (0.7 × 10¹⁰ CFU/g)/kg, and 6 g LYSc (0.7 × 10¹⁰ CFU/g)/kg were prepared and fed to 180 fish (mean weight = 8.0 g; 3 aquaria per treatment; 20 fish per aquaria) distributed in a completely randomized design for 56 days before 10 fish per aquarium were challenged with A. hydrophila for 14 days. Fish fed on 6 g/kg of FYSc exhibited significantly (P < 0.05) improved final body weight (93.1 g; +42.1%), weight gain (85.1 g; +48.0%), and specific growth rate (4.4%/day; +16.2%) compared to control fish. Lysozyme and respiratory burst activities and superoxide dismutase, catalase, and glutathione peroxidase, reduced glutathione significantly (P < 0.05) enhanced in FYSc groups as well as gut acetic (12.2 nmol/L) and butyric (1.0 nmol/L) acids than the control group. Post A. hydrophila mortalities were reduced from 53.3% in the control to as low as 13.3% in the FYSc group. However, no significant variations were observed between FYSc and LYSc based fish. Dietary S. cerevisiae, enhances growth, health, and disease resistance in African catfish, particularly locally sourced yeast thus offering a sustainable strategy for aquaculture.