author(s)
Irfan Rasool, Kamal Kant Jain, Narottam Prasad Sahu, Sujata Sahoo, Adnan Hussain Gora, Saima Rehman and Showkat Ahmad Dar

abstract
A 45-day feeding experiment was carried out to evaluate the growth, conversion efficiency and body composition of zebrafish by altering the protein-carbohydrate ratio in the diet. One hundred and Eighty Zebrafish (Danio rerio) having an average weight of 0.20 ±0.03g were randomly distributed in three experimental groups with 20 fish in each replicate. Fish were fed with three iso-lipidic diets (crude lipid 8%) that contained three different levels of protein and in each protein level, three different levels of carbohydrate (T1:25% protein, 45% carbohydrate; T2- 35% protein and 45% carbohydrate; -T3-45% protein, 25% carbohydrate) were included. The growth performance of the experimental fish was evaluated. The results demonstrated that T1 group exhibited higher growth rate (SGR), feed efficiency ratio (FER) and protein efficiency ratio (PER) but lowest weight gain (% WG), as compared to T2 and T3. Feed conversion ratio was also significantly higher in T1 as compared to T2 and T3 groups. However, there was no significant difference in the protein efficiency ratio between T1 and T2, whereas it was significantly reduced in T3 group. A significant decrease in the whole body moisture, protein content, and increase in whole-body lipid content was observed in group T1. The present study shows that optimum protein levels in the diets may be reduced to 25% protein while carbohydrate levels can be increased up to 45% to formulate the feed with more inclusion of digestible carbohydrate based on the growth performance and protein utilization in zebrafish.