Effects of different levels of dietary protein and lipid on the skin mucus immune indices in Zebra fish, Danio rerio

The zebra fish, Danio rerio is an ornamental freshwater fish. It is important because of beautiful appearance, economic value and has emerged as a pre-eminent vertebrate model for studying genetics. The use of appropriate diets is one of the most important biological components for growth and health fish. Since, protein and lipid are the main components of diet, in this feeding trial, we compared the effects of 9 diets with 3 protein levels (25, 30 and 35%) and 3 lipid levels (4, 8 and 12%) to evaluate the protein and lipid ratio on skin mucus immune indices of zebra fish. A total of 135 pieces of fish were divided into five groups with an average biomass (± SD) of 1.23 ± 0.02 g and a sex ratio of 2 to 3 (male / female) were randomly distributed into 27 aquaria (20-L) and fed 3 times daily during 4 months. Results showed that activity of lysozyme, alkaline phosphatase enzymes and soluble protein of zebra fish were  significantly higher in the fish fed 35% protein and 12% lipid (p<0.05). In conclusion, protein and lipid have a positive effect on skin mucus immune indices in zebra fish.