Bluegill ( Lepomis macrochirus ) is a popular game fish in North America. This study investigates the growth performances and gut microbiota of bluegill fed a commercial (CO) diet and an alternative (AT) diet with hemp protein meal in a recirculating system. Using a complete randomized experimental design, with three tanks per diet, 120 bluegills with an initial average weight of 12.67 ± 0.14 g were fed twice daily to apparent satiation for six weeks, and growth parameters were monitored. The results revealed the ability of the fish to utilize the AT diet, but the responses differed between the two diets. Growth was significantly higher in fish fed the CO diet than in the AT diet ( P < 0.05). Similar trends were obtained for feed conversion ratio, FCR and specific growth rate, SGR ( P < 0.05). The amplicon data revealed Fusobacteria, Firmicutes, Proteobacteria, and Bacteroidota as the major bacterial phyla in the bluegill intestinal samples. Bacteroidota was detected in high abundance in the AT diet-fed bluegill. The findings from this study demonstrated the ability of bluegill to grow on an AT diet and the feasibility of incorporating alternative ingredients, such as hemp protein meal, into the diet for its farming to support the expansion and sustainability of the aquaculture industry. The results may provide insight into future studies on developing a practical diet that meets the nutritional requirements and enhances the growth of beneficial gut microbes in bluegill. • The performance of bluegill fed plant and commercial diets was evaluated. • The gut microbiota of bluegill fed the diets was investigated. • Growth was significantly higher in fish fed the CO diet compared to those fed the AT diet. • C18:2n6 and C18:3n3 pathways were affected by dietary treatment. • A high abundance of the Bacteroidota phylum was found in the AT diet-fed bluegill.
Betiku et al. (Tue,) studied this question.