The effect of different levels of Bacillus probiotic extracellular enzymes on growth, nutrition and survival parameters of Rainbow trout Oncorhynchus mykiss (Walbaum, 1792) larvae

This study was conducted to evaluate the effects of enzymes produced by five Bacillus probiotics on growth and nutritional parameters of rainbow trout (Oncorhynchus mykiss) larvae with an initial body weight of 0.53 ± 0.19 g during 60 days. The enzyme suspension produced by Bacillus probitics resulted from culturing the bacilli in broth media with three concentrations of 1×106, 1×107 and 1×108 CFU/100g were inoculated into the diet of rainbow trout larvae. The results of larval biometry at the end of the period of the experiment showed the following: First, the use of enzyme suspension, produced by the highest concentration of Bacillus (1×108 CFU/100g) fed in T3 treatments (20.02 ± 3.77 g), caused a significant increase in the weight growth (P