Effect of Chitin Supplemented Diet on Innate Immune Response of Rai

Chitin is a natural polymer found abundantly in the shells of crustaceans, insects and in fungi. Chitin and its deacetylated product chitosan are commercially manufactured from shells of shrimp and crab. Four experimental diets containing 0 (control), 10, 25 and 50 mg/kg chitin were prepared in the laboratory from a commercial pellet diet. A total of 50 rainbow trout were divided randomly into four groups, each receiving one of the above mentioned diets. Six fish from each group were randomly sampled. Blood samples were collected from the caudal vein on days 0, 7, 14, 21, 28, 35 for haemolytic complement activity and NBT assay. When fish were fed with chitin supplemented diets for 5 weeks, this activity increased to a statistically significant degree. Studies on neutrophil activity showed the enhancing effect of dietary supplements on neutrophils respiratory burst activity as evidenced from the increased NBT reduction. Based on the results of the present study, it can be concluded that the administration of a chitin diet (10, 25 or 50 mg/kg) enhances rainbow trout immune activity through the non-specific modulation of haemolytic complement activity and leukocyte respiratory burst activity.