The culture of the cinnamon river prawn Macrobrachium acanthurus has been suggested for several years to overcome the possibility of its disappearance caused by several human-related factors. The assessment of nutrient requirements is an important step to develop the culture and cholesterol is an essential nutrient for crustaceans that serves as precursor of sex and molting hormones, adrenal corticoids, and vitamin D. Thus, the present study was aimed to determine the dietary requirements of cholesterol in juvenile M. acanthurus .
A 60-days feeding trial was performed with prawns of an initial weight of 0.24 ± 0.0 8 g (mean ± SD). A basal diet (crude protein, 39 ± 0.6% ; crude 8 lipid 12 ± 1%; ash 5 ± 0.1%, and moisture, 3 ± 0.3%, mean ± SD) was added with 0.5 (Chlo-0.5) , 1 (Chlo-1.0 ) and 1.5 (Chlo-1.5 ) g of cholesterol per 100 g of diet. Basal diet without cholesterol addition (Chol-0 ) was used as control. Each diet was fed to triplicated groups of 5 organisms per replicate at a 9% of the total biomass. Obtained data was analyzed with a one-way ANOVA and significant differences were evaluated with a Fisher LSD test (P <0.05).
Data of weight gain (WG ) and specific growth rate (SGR) of prawns fed with diets Chlo-0 and Chol-0.5 were significantly lower than those observed for the groups of Chol-1.0 and Chol-1.5 (TABLE 1). Survival rate was significantly higher in the group Chlo-1.0 . Higher contents of protein in the muscle were observed when cholesterol increased in the diet, but no significant differences were found . A similar trend was observed in the muscle contents of lipids. The present results indicate that dietary inclusion of cholesterol should be around of 1.0 g per 100 g of diet for juveniles M. acanthurus.
TABLE 1. F inal weight (FW), weight gain (WG), specific growth rate (SGR) and survival of juvenile M. acanthurus fed different levels of cholesterol. Means (± SE) in the same line with different levels were significantly different (P<0.05).