Abstract
A 60-day feeding trial was performed to determine the effects of diets with two levels of protein (35 and 40%) and three lipids to carbohydrate ratios (L:C ratios 2:1, 1:2, and 1:6) in the gene expression of lipid (acetyl-coA carboxylase, acc; fatty acid synthetase, fas; carnitine palmitoyl transferase-1, ctp1), carbohydrate (hexokinase, hk; glucose-6-phosphatase, g6p; phosphoenol pyruvate carboxylkinase, pepck), and the antioxidant (catalase, cat; glutathione peroxidase, gpx; super oxide dismutase, sod) metabolism in the juvenile Macrobrachium acanthurus. Each diet was fed to triplicate groups of ten organisms with an initial weight of 0.075 ± 0.015 g (mean ± SD) and after the 60 days, the thermal-unit growth coefficient (TGC) was calculated and samples of the hepatopancreas and gills were obtained, and then gene expression was determined. The TGC showed higher values in diets with 35% protein, but no significant differences were observed with respect of 40% protein treatments. acc and fas expressions were lower in the treatments 35% protein. In the 40% protein, the high expressions of fas and acc indicate an accumulation of lipids, while expression of pepck shows that glucogenic amino acids are used to synthetize glucose. Protein 35% improved the expression of antioxidant genes in the hepatopancreas but decreased in the gills. According with this, a level of 35% and L:C ratio of 1:2 seems to be an adequate combination of the macronutrients for the juvenile M. acanthurus.