Nutritive value of soybean meal after solid state fermentation with Saccharomyces cerevisiae for Nile tilapia, Oreochromisniloticus

Commercial soybean meal (CSBM) was fermented with Saccharomyces cerevisiae using the solid-state fermentation (SSF). Yeast fermentation increased the protein content of CSBM by 13.65%, increased the total of hydrolyzed amino acids by 16.27% and decreased phytic acid and tripsin inhibitor. A feeding trial was conducted to investigate the effect of yeast fermented soybean meal (YFSBM) on the growth, feed utilization, hematological and biochemical blood parameters of Nile tilapia Oreochromisniloticus. Five isonitrogenous (295 g/kg crude protein and isocaloric 19.5 MJ/kg gross energy) practical diets were formulated by replacing 0% (D-0), 25% (D-50), 75% (D-75) and 100% (D-100) of protein from fish meal with YFSBM. Each diet was fed to three replicate groups of fish with an initial weight 3.49 ± 0.09 g for 84 days. Using polynomial regression the best final body weight (FBW), weight gain (WG), specific growth rate (SGR), protein efficiency ratio (PER) and protein productive value (PPV) were recorded by fish fed D-25. Based on FCR, broken-line model estimated the optimum level of YFSBM to replace FM is at 37.4%. The best apparent digestibility coefficients (ADCs) were recorded by fish fed the D-25 followed by D-50 using a linear model. Best fit was obtained using a linear model for chemical composition. Body protein and ash contents tended to be higher and reached a plateau in fish fed D-25 and D-50. However, fit linear model showed that the lowest dry matter (DM), lipid and gross energy (GE) contents occurred at 0% replacement. Using linear regression analysis, non-significant effect of YFSBM inclusion level on Htc and Hb was found. The same pattern was observed in WBCs, RBCs, IGF-I, C3 and GH increased and ALT and AST decreased with D-25 and D-50, respectively and the best fit of the data were obtained using polynomial regressions.