Evaluation of the use of alpha-amylase, cellulase, xylanase, and beta-glucanase enzymes in vitro and in vivo on non-specific immune indices, intestinal bacterial flora, cholesterol, and blood glucose of rainbow trout

One of the limitations of aquaculture is the supply of fish meal needed for the aquaculture industry, but the use of plant items instead of fish meal contain anti-nutrients such as non-starch polysaccharides, which is one of the main limitations of using plant items in the diet of carnivorous fish. The present study investigated the in vivo and in vitro enzymes of alpha-amylase, cellulase, xylanase, and beta-glucanase on 210 rainbow trout (weight average 17.17 ± 3.85) in 7 treatments (three replications) including adding enzyme mixtures 24, 12, 6, 3 hours before production, the enzyme was added during production and after production for 60 days. First, the enzymatic composition for wheat flour and soybean meal was designed by in vitro test.The required enzyme levels of alpha-amylase, cellulase, xylanase, and beta-glucanase for wheat flour are 0.5, 0.1, 0.3 (g/kg), and 0.2, respectively, and for soybean meal are 0.5, 0.2, 0.5, and 0.1 (g/kg), respectively. . After producing the diets, feeding was done three times a day until satiety. At the end of the experiment, 3 fish were randomly sampled from each replicate to measure the total bacterial flora, intestinal lactobacilli, and measure blood parameters. According to the results, enzymes were not effective on white blood cells, red blood cells, hematocrit, and complement index, but increased serum cholesterol and triglyceride levels in the treatment of adding enzyme mixture 6 hours before production. Glucose levels were higher in the treatments of adding enzyme mixture 3 and 6 hours before production. The number of intestinal lactobacilli was higher in treatment of adding enzyme mixture 6 hours before production. And serum lysozyme in the treatment of adding the enzyme mixture 6 hours before production is higher than other treatments.In general, the results of this study show that the use of enzymes in the diet of rainbow trout changes the bacterial population of the intestine and the time of adding the enzyme to food items changes the efficiency of the use of enzymes.