Effect medicinal plants powder, stocking density and dietary aflatoxin contamination on digestive enzymes activity of rainbow trout

The effect of stocking density and dietary aflatoxin B1 along with rosemary and thyme powders on intestinal digestive enzymes activity of rainbow trout was evaluated. Total of 600 fish with an average weight of 90±3 were randomly allotted among six experimental groups consisted of two stocking density (15 and 45 kg.m-3), aflatoxin contamination (0 and 50 ppb) with/without including 4 % herbal blend powder (2% rosemary and 2% thyme). Each treatment was replicated thrice and the experiment was lasted for 6 weeks. Stocking at high density and receiving aflatoxin B1 contaminated diet resulted in higher digestive enzymes activity including amylase, lipase and alkaline protease (p≤0.05). It seemed that including herbal blend consisting of rosemary and thyme powder could mitigate pathologically elevated digestive enzymes activity due to dietary aflatoxin contamination (p≤0.05). In conclusion, dietary inclusion of rosemary and thyme multi-blend in aflatoxin contaminated diets at the studied level could ameliorate undesirable effects of aflatoxin on intestinal digestive enzymes activity of rainbow trout reared at various densities.