Effects of Varying Quantities of Dietary Protein and Lipid on Growth Performance, Blood Biochemical Parameters, Digestive Histology and Enzyme Activity in Juvenile Gold Fish (Carassius auratus)

Background: Goldfishes are used as an ideal model for nutritional studies in larval and juvenile cyprinids. However, of the limited published data that is available on goldfish, protein requirements have varied from 29% to 53% for goldfish larvae. So the present study was undertaken to determine growth performance of goldfish, C. auratus fed with different dietary protein and lipid levels to develop nutritionally balanced diets. Methods: In this study, Carassius auratus juveniles were fed with six diets containing two protein levels (300 and 400 g/kg) and three lipid levels (40, 80 and 120 g/kg) to evaluate the optimal dietary protein and lipid levels to determine growth performance, blood biochemical parameters, digestive enzyme activity and intestinal and liver histology. Result: According to the findings, gold fish juveniles when fed a casein-dextrin based semi-purified diet containing 400 g/kg dietary protein and 80 g/kg dietary lipid content, maximum development and feed utilisation are seen. Second-order polynomial regression also suggests that a diet with 400 g/kg protein and 80 g/kg lipid is best for juvenile goldfish growth and feed utilisation.