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Mandarin fish is a typical carnivorous fish, it can accept artificial diet after domestication, which is significantly essential to optimize its artificial diet. Nevertheless, only few studies were conducted on artificial diet of mandarin fish. Therefore, an 8‐week feeding trial was conducted to evaluate the influence of feeding stimulants on growth performance, feed intake and appetite regulation of mandarin fish. In this trial, six diets were formulated, a basal diet contained 80% of Fish Meal without feeding stimulants, named as Control, 0.4% inosinic acid meal, 0.4% L‐Alanine meal, 3% Yeast meal, 3% a commercial squid extract meal and 0.4% betaine meal were added into the basal diet to make five experimental diets, which were named as IM, AM, YM, SVO and BM respectively. At the end of feeding trial, SVO group showed higher feed intake, up‐regulated mRNA expression of neuropeptide Y (NPY) and down‐regulated mRNA expression of pro‐opiomelanocorticoid (POMC) significantly as compared to control group, which suggested that squid extract improved feed acceptability and promoted appetite in mandarin fish. Similarly, compared to control group, SVO group showed low food conversion ratio, high weight gain and SGR, indicated that squid extract enhanced the growth performance. Our results suggested that the appropriate level of squid extract addition could contribute to optimize artificial diet in mandarin fish. [ABSTRACT FROM AUTHOR]

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]