Largemouth bass (LMB) are a popular sportfish in the U.S., and increased attention has given promise for this species to be cultured as a food fish. The aquafeed industry relies on animal protein as the primary ingredient in dietary formulations. Due to increased consumer demand, price volatility, and the risk of exploitation of aquatic species, the industry has pushed for a more sustainable approach to dietary formulation. New alternative protein sources such as poultry-by-product (PBP) and soybean meal (SBM) have displayed the potential to serve as replacement protein sources in formulated diets to influence the growth performance and health of several aquaculture species. Currently, the price and supply of SBM have become highly unstable due to global conflicts, which have caused turmoil in the supply chain. The search for a new alternative protein source is dire to keep aquafeed production profitable yet sustainable. The U.S. is one of the biggest producers of ethanol and fermented corn protein (FCP), which is one of the by-products of the ethanol industry. The CFP has served as an excellent protein source in feed production for the agriculture industry.
To evaluate the potential replacement of SBM with FCP, this study investigated growth performance health in LMB fingerlings. Twenty individual tanks, within a recirculating aquaculture system (RAS), were each stocked with twenty LMB fingerlings (21.76 ± 0.13 g). The fish were fed one of the four experimental (5, 10, 15, and 20% FCP) diets or the control (0% FCP) diet for 12 weeks. This trial is currently ongoing. No differences in tank biomass (P = 0.279), average individual weight (P = 0.086), FCR (P = 0.199), tank biomass gained (P = 0.144) have been detected after four weeks. On the contrary, differences in weight gain (%; P = 0.018) and thermal growth coefficient (TGC; P = 0.025) have been observed. At the conclusion of the growth trial, fish will be sampled for whole-body proximate analysis, blood chemistry (including serum lysozyme), intestinal and liver gene expression, and histological analyses. Similar to soy-based proteins, FCP could provide benefits to growth performance all while reducing LMB production costs. Furthermore, this ingredient may provide potential health benefits to increase production efficiency.