Evaluation of protein: lipid ratio on growth, feed efficiency, and metabolic response in juvenile yellowtail snapper Ocyurus chrysurus (Bloch, 1791)

This study was conducted to evaluate juveniles' Ocyurus chrysurus (13.7 ± 0.45 g initial weight) utilize lipid as an energy source on growth, feed efficiency, body composition, digestive and hepatic enzyme activities. Four diets of two protein levels (40 50%) with (6 12%) 2% digestible carbohydrates were formulated. Fish fed for 60 days apparent satiation at a stocking density 10 fish per tank (100 L). Growth gain 50% dietary higher than 40% (P < 0.05). However, efficiency significantly 12 6% lipid. Whole-body glycogen in the liver increased dramatically content-alkaline protease activity trend increased. Trypsin decreased, whereas chymotrypsin showed opposite Bile salt-dependent lipase towards increasing decreased. Glucose-6-phosphate dehydrogenase (G6PDH), 6-phosphogluconate (6PGDH), fructose-1, 6-biphosphatase (FBPase) levels. alanine aminotransferase (ALT) content. On other side, pyruvate kinase (PK) both indicates that high (12%) improved but did not reduce demand juveniles O. chrysurus.