With the growing aquaculture industry, the exploration of alternative ingredients is crucial for the sustainability of aquaculture feed. While alfalfa meal is commonly used in animal feed, its use in aquatic feed remains limited. This study conducted two feeding trials to evaluate the potential of using alfalfa nutrient concentrate (ANC) as a partial replacement for fishmeal in the diet of yellow perch, a cool-water fish native to the Great Lakes region. The aim was to investigate alternative sources of protein for fishmeal and provide a new revenue stream for alfalfa producers. In the first trial, we assessed the growth performance of yellow perch fed diets containing varying levels of ANC (0, 5, 10, 15, and 20 g/100 g diet) to replace fishmeal in a control diet. The trial lasted 9 weeks with three replications for each diet. The growth rate, feed conversion ratio, satiation feed intake, and protein retention were similar (P > 0.05) across all diets. However, fish fed the ANC-20 diet had lower levels of ash, phosphorus, calcium, and manganese compared to those fed the ANC-0 diet (P < 0.05). A lower apparent digestibility coefficient for phosphorus was observed in the ANC ingredient compared to menhaden fishmeal, which partially explains the reduced phosphorus content in fish fed the ANC-20 diet.
The second 9-week second trial investigated the growth performance of yellow perch fed the ANC-20 diet supplemented with varying levels of phytase (0, 312.5, 625, 1250, 2500, and 5000 FTU/kg diet) compared to a control diet without ANC. Polynomial regression analysis revealed that the optimal growth rate was achieved with phytase supplementation at 1666 FTU/kg diet, highlighting the potential benefits of phytase in ANC-based diets. This study suggests that ANC can serve as a partial protein source to replace fishmeal in perch feed. However, longer-term feeding trials are needed to validate these findings, and the cost-effectiveness of using ANC in aquatic feed should be considered.