Effects of dietary replacement of fish meal by soybean meal on growth,feed utilization,and health condition of stinging catfish,Heteropneustes fossilis

Soybean meal (SBM) is a cost-effective alternative protein source to replace costly fish meal in aquaculture. This present study determined to measure the effects of replacing fish meal (FM) protein with SBM on growth, feed utilization, and health condition of stinging catfish, Heteropneustes fossilis. Four isonitrogenous (35 %) diets were applied in four treatment groups designed as SBM₀, SBM₂₅, SBM₅₀, and SBM₇₅, where 0 %, 25 %, 50 %, and 75 % of FM protein were substituted by SBM, respectively. Significantly higher mean final weight (g), weight gain (g), percent weight gain (%), specific growth rate (% day^?1), and protein efficiency ratio (PER) were recorded in SBM₀, SBM₂₅, and SBM₅₀ groups than SBM₇₅ group. Consequently, significantly lower feed conversion ratio (FCR) was found in SBM₀, SBM₂₅, and SBM₅₀ groups than SBM₇₅ group. Moreover, protein content of whole-body carcass was significantly higher in SBM₂₅ and lower in SBM₀ group however, lipid content was significantly higher in SBM₀ and SBM₇₅ than in other groups. Hemoglobin, red blood cells, and white blood cells were significantly higher in SBM₀, SBM₂₅, and SBM₅₀ groups compared to SBM₇₅. However, the higher the substitution of FM protein by SBM in diets higher the values of glucose. Morphological analysis of the intestine including villi length (μm), width (μm), and area (mm²); crypt depth (μm); wall thickness (μm); abundance of goblet cell (GB); and muscle thickness (μm) showed an increasing trend in fish fed diet containing upto 50 % replacement of FM protein by SBM. Therefore, the results suggest that SBM could replace upto 50 % FM protein in diets of H. fossilis without compromising growth, feed efficiency, and health status.