A 10 week feeding trial was conducted to evaluate the effects of different dietary soybean oil (SO) levels on growth performance, fatty-acid composition and lipid deposition in viscera, histology and histochemistry of liver, intestine and hepatic-lipid metabolism-related gene expressions in pond loach Misgurnus anguillicaudatus juveniles. Misgurnus anguillicaudatus (mean ± s.d. mass 0·40 ± 0·01 g) were fed five experimental diets containing SO at different concentrations: 0, 20, 32, 56 and 100% SO and a diet containing 100% fish oil (100% FO). The mass gains and specific growth rates of M. anguillicaudatus fed 20% SO and 100% FO diets were significantly higher than those of the other groups (P < 0·05). The lipid content of viscera and the amount of cytoplasmic vacuolation in the liver increased with incremental dietary SO level. Meanwhile, increasing dietary SO levels up-regulated the messenger (m)RNA levels of lipogenic genes (such as Δ6fad, scd, ppar , fas and srebp-1) and down-regulated the mRNA levels of the lipolytic genes (such as ppar , cpt1, atgl and hsl) in the liver. The percentage of 20:4n-6 significantly (P < 0·05) increased with increasing dietary SO level, which might be correlated with the up-regulation of the mRNA level of Δ6fad. The highest levels of dietary SO, however, had a negative effect on growth performance, lipid deposition of viscera and histology and histochemstry of liver and intestine. The increased lipid accumulation induced by incremental dietary SO level probably occurred through different strategies for lipid metabolism as a result of competition between lipolysis and lipogenesis and between export and import of lipids in this species.

. 2008. Insulin induced lipogenesis and enhanced mRNA level of sterol regulatory element binding protein-1c in primary porcine adipocyte. Can. J. Anim. Sci. 88: 419Á424. Little is known about the development and metabolism of the pig adipocyte, and even less is known about regulation of lipogenesis in the pig adipocyte. The objective of this study was to test the effects of insulin on the morphology of cells, the content of triacylglycerols (TG), the activity of fatty acid synthase (FAS) and the mRNA level of sterol regulatory element binding protein-1c (SREBP-1c) in porcine adipocytes in vitro. Morphologically, larger lipid droplets appeared in the presence of insulin for 48 h. Insulin-induced lipogenesis of primary porcine adipocytes was correlated with the TG content and FAS activity. There was a significant difference in the TG content and FAS activity between the insulin-treated cells and the control cells (P B0.05); insulin increased the content of TG and FAS activity in a dose-dependent manner and the maximum activity occurred at 150 nmol L (1 . The TG content and FAS activity were increased in a dose-dependent manner and maximal values were obtained when adipocytes were incubated with 150 nmol L(1 insulin. The mRNA levels of SREBP-1c were also increased by insulin. In summary, lipogenesis of porcine adipocyte could be induced by insulin in a dose-dependent manner and the induced hypertrophy of porcine adipocytes partially due to the increase of TG content, FAS activity and SREBP-1c mRNA level.