Evaluation of Yellow Bean (Phaseolus vulgaris) as a Fish Feed Ingredient: Effects on Growth, Blood Parameters, and Immunology in Nile Tilapia (Oreochromis niloticus)

This study evaluated the dietary inclusion of Yellow Bean (Phaseolus vulgaris L.) concentrate as a sustainable plant-based protein source in the diets of Nile tilapia (Oreochromis niloticus), aiming to assess its effects on growth, hematological, and immune parameters. A total of 450 juvenile tilapia (11.6 ± 0.1 g) were fed diets containing graded inclusion levels of Yellow Bean concentrate—0% (control), 25%, 50%, 75%, and 100%—over a 60-day feeding trial. Growth performance indices, blood biochemical parameters, and non-specific immune responses were measured. The results revealed that partial substitution of conventional protein sources with Yellow Bean at 25–50% inclusion levels significantly improved key performance indicators such as feed intake (FI = 60.6 g in YBD-4), catalase activity (CAT = 13.7 U/mg), and plasma lysozyme activity (6.10 U/ml) (p < 0.05), without compromising fish health. The highest survival rate (97.5%) was observed in the 100% inclusion group (YBD-5), although feed conversion efficiency declined at higher inclusion levels. These findings suggest that 25–50% Yellow Bean inclusion offers an optimal balance of growth and immune enhancement, indicating its potential as a viable and eco-friendly alternative protein ingredient for tilapia aquaculture.