The Effect of Different Levels of Dietary Protein and Lipid on Growth Indices and Reproductive Performance in Zebra Fish (Danio rerio)

Inroduction & The use of appropriate diets is one of the most important biological components for growth and health fish, and also it effects on fertility, egg production and egg quality. In this research, the effect of different levels of protein and lipid on growth indices and reproduction performance in zebra fish (Danio rerio) was investigated. 9 diets with 3 protein levels(25, 30 and 35%) and 3 lipid levels (4, 8 and 12%) was conducted to evaluate the protein and lipid ratio for optimum growth and reproduction of zebra fish. 135 fishes were categorized into five groups with an average biomass (± SD) of 1.23 ± 0.02 (gr) and with a sex ratio of 2 to 3 (male / female) were randomly distributed into 27 aquaria (20-liter) and fed 3 times daily during 4 months. The results revealed that the interaction between protein and lipid increased the weight, body weight gain, dietary efficiency, fish growth rate and survival (P <0.05), but feed conversion ratio reduced significantly (P <0.05). Increasing dietary protein levels increased (P <0.05) nutritional efficiency, specific growth rate, percentage of body weight gain, weight and survival of the larvae and decreased conversion ratio of food and daily food intake significantly (P <0.05). Body weight gain, nutritional efficiency, growth rate, weight gain and survival of the larvae was significantly higher (P <0.05) and feed conversion ratio was lower (P <0.05) in the fish fed 12% lipid. The diet containing 35% protein with 12% lipid would be suitable for optimum growth and reproduction of zebra fish.