Inhibitory Effect of Prickly Ash (Zanthoxylum bungeanum) Seed Kernel Oil on Lipid Metabolism of Grass Carp (Ctenopharyngodon idellus) in High-Fat Diet

Abstract

To investigate the effect of prickly ash (Zanthoxylum bungeanum) seed kernel oil (PASO) on the lipid metabolism of grass carp (Ctenopharyngodon idellus) under a high-fat diet, PASO were added into two lipid-level (4 g/kg and 8 g/kg) diets to form four isonitrogenous diets: soybean oil (SO), PASO, high-fat soybean oil (HSO), and high-fat prickly ash seed oil (HPASO). A total of 216 healthy grass carp (9.43 ± 0.82 g) were randomly divided into four groups and fed with the four diets, respectively, for 56 days. The result showed that the viscerosomatic index (VSI) and the content of the crude lipid in the hepatopancreas and muscle was significantly higher by oil levels (p < 0.05). The linolenic acid content in the body of the fish significantly increased in PASO and HPASO compared to that in SO and HSO (p < 0.05). The fatty acid composition of the hepatopancreas, intraperitoneal fat, and muscle in four dietary groups was significantly similar to the fatty acid composition in the diets (p < 0.05). More significant fat infiltration and nuclear translocation in the hepatopancreas of fish was found in the HSO group but was decreased in the HPASO group. The adipocyte size in the intraperitoneal fat tissue in the PASO group was significantly lower than that in the SO group (p < 0.05). The relative mRNA expression of the lipogenesis-related genes ppar-γ, cebp-α, and srebp-1c was significantly down-regulated in the PASO group compared with the SO group (p < 0.05), and the mRNA expression of lipolysis-related genes ppar-α and cpt-1 were significantly up-regulated in the PASO group (p < 0.05). In conclusion, dietary PASO showed the function of reducing lipid accumulation in the fish. This reduction might be attributed to the inhibition of the lipogenesis-related genes and the stimulation of the lipolysis-related genes, which were probably modulated by the high content of linolenic acid in PASO.