Optimizing protein, lipid and carbohydrate levels in diets for growth of juvenile hybrid grouper (Epinephelus fuscoguttatus ♀ x E. lanceolatus ♂)

Hybrid grouper (Epinephelus fuscoguttatus female x E. lanceolatus male) that is well known as "cantang" has a good prospect for aquaculture due to its high economic value, fast growing and good acceptance to compound feed. However, information on feed specification for this grouper is still limited. Therefore, this research aimed to find out the good proportions of protein, lipid and carbohydrate in feed for hybrid grouper. Six experimental diets were formulated with protein contents of 48, 44 and 40%, which then combined with lipid contents of 9-17% and carbohydrate contents of 15-32%. Juvenile hybrid grouper of 4.8 +/- 0.6 g body weight were stocked into 24 fiber tanks, 400 L in volume, with a density of 40 fish/tank. Fish were fed experimental diet twice every day for 56 days. Resuls of the experiment showed specific growth rate (SGR) of fish fed 48% protein diet was not significantly different with SGR of fish fed diet containing 44% protein, 14% lipid, 15% carbohydrate and SGR of fish fed diet containing 40% protein, 16% lipid, 15% carbohydrate. The best protein efficiency ratio and protein retention were achieved in fish fed diet containing 44% protein, 14% lipid and 15% carbohydrate as well as in fish fed diet containing 40% protein, 16% lipid and 15% carbohydrate. This result suggested feed containing 44% protein, 14% lipid and 15% carbohydrate or feed containing 40% protein, 16% lipid and 15% carbohydrates was effective in increasing dietary protein efficiency and support good growth for juvenile hybrid grouper cantang.