محمود نفیسی بهابادی

The purpose of this study was to investigate effects of macro alga flour replacement with fish meal on immunity, intestinal tissue and liver antioxidant enzymes of Lates calcarifer. In this case, 120 pieces of Asian sea bass with an average weight of 28 ± 0.5 g were divided into four treatments and three replicates were divided into 12 tanks of fiberglass 300 liters (10 fish per tank). Practical diets were prepared using blends of soybean meal and fishmeal used as control diet (C) supplemented with 3 (GL3%), 6 (GL6%), and 9% (GL9%) G. pygmaea. The results of this study showed that the alga flour replacement with fish meal in diet of Asian sea bass immunoglobulin content significantly increasein fish fed GL6% diets. Increasing dietary supplementation of G. pygmaea decreased the serum alternative complement activities when compared to control group. The inclusion of Gracilaria in the dietled to evident changes in the fish antioxidant status with significant reduction of glutathione S-transferase, glutathione reductase and lipid peroxidation. The histological study showed that all groups of fish indicate normal morphology of anterior intestine and pyloric caeca. Overall, the results obtained in this study indicate that dietary G. pygmaea supplementation improves growth performance in Asian sea bass without compromising immune response, antioxidant responses and digestive function.