Potential use of macro-algae Gracilaria lemaneiformis in diets for the black sea bream, Acanthopagrus schlegelii, juvenile

In this study, diets containing 5, 10, 15, and 20% Gracilaria lemaneiformis (GL) (D1-D4 diet) were prepared to investigate the effects of GL on growth performance, carcass composition, activities of digestive enzymes, transaminases activities of black sea bream (Acanthopagrus schlegelii) juvenile. Weight Gain (WG) and Feed Efficiency Ratio (FER) of the fish fed D4 diet were significantly lower than that of control group. Fish fed with the D4 diet showed significantly lower crude lipid of both body and liver and Hepato-Somatic Index (HSI) than those fed with the control diet. Activities of pepsin in the stomach, lipase and amylase in the anterior intestine were significantly suppressed in fish which were fed with the D4 diet (P < 0.05). On the other hand, the activities of serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were significantly higher in fish which were fed with the D4 diet (P < 0.05) than that of the control group. These results indicate that incorporation of the GL in the diet at up to 15% level for juvenile black sea bream is feasible in terms of the growth performance and the physiological state.