Mixed culture microorganisms fermented soybean meal improves productive performance and intestinal health of Nile tilapia (Oreochromis niloticus) juveniles fed plant‐based diets in a biofloc system

摘要

Abstract This study aimed to evaluate the effect of plant‐based diets containing different inclusion levels (7, 14, 21 and 28) of mixed culture microorganisms fermented soybean meal (FSBM) on the zootechnical performance and intestinal health of juvenile Nile tilapia (Oreochromis niloticus) reared in a biofloc system. The FSBM diets were compared with a positive control diet with fish meal and a negative control diet with no animal protein. All diets were isoprotein (33 CP) and isoenergetic (4300 kcal GE/kg). The design was completely randomized with four replications and the experiment lasted 54 days. Juveniles (1.635 ± 0.198 g) were distributed in 24 tanks (70 L) at a density of seven animals per tank. Fermentation increased probiotic microorganisms count (lactic acid bacteria 4.75 ± 0.21 log CFU g−1 and yeast 3.30 ± 0.54 log CFU g−1) and improved nutritional characteristics of FSBM. In fish fed the diet containing 7 FSBM, growth performance did not differ from fish fed the fish meal diet. FSBM inclusion improved the food efficiency of plant‐based diets. The inclusions above 21 of FSBM increased the intestinal villi height. In the inclusion of 28 of FSBM, the goblet cell was higher compared to that of the other plant‐based diets. The inclusion of 7 FSBM allows a total replacement of fish meal without compromising the growth performance of the animals.