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A study was conducted to determine the effects of dietary non-protein energy sources on growth, tissue lipid accumulation and lipid metabolism-related genes expression of grass carp. Triplicate groups of fish were fed for 9 weeks on four isonitrogenous (300 g kg−1) experimental diets with four levels of non-protein energy (6.52 kJ g−1 control diet, 5.32 kJ g−1 high- CEL diet, 8.46 kJ g−1 high- CHO diet and 8.53 kJ g−1 high- LIP diet respectively). Increasing dietary non-protein energy source levels did not improve the growth, and the high- CEL diet reduced the growth of grass carp. The high- CHO diet tended to induce high hepatosomatic index, with high fat and glycogen content of liver. However, the high- LIP diet caused the high mesenteric fat index, but did not increase liver fat. The m RNA abundance and activities of hepatic lipogenic enzymes were significantly increased in the high- CHO diet group, whereas the opposite tendencies were observed in the high- LIP diet group. Peroxisome proliferator-actived receptor-α ( PPARα) in liver and PPARγ in mesenteric adipose tissue were up-regulated in the high- CEL diet group. Lipoprotein lipase ( LPL) gene expression was significantly increased both in liver and mesenteric adipose tissue of fish fed the high- LIP diet, while the LPL gene expression was up-regulated in liver but down-regulated in mesenteric adipose tissue of fish fed the high- CEL diet. These findings suggest that an increase in dietary non-protein energy sources alters the genes expression of lipid metabolism and increased lipid deposition. [ABSTRACT FROM AUTHOR]