水飞蓟素对杂交石斑鱼幼鱼血清生化指标、脂代谢相关基因表达及肝脏代谢组的影响

Effects of Dietary Silymarin Supplementation on Serum Biochemical Parameters,Lipid Metabolism-Related Gene Expression,and Liver Metabolome in Juvenile Hybrid Grouper(Epinephelus fuscoguttatus♀×Epinephelus polyphekadion♂)

【目的】探究饲料中添加水飞蓟素对杂交石斑鱼(Epinephelus fuscoguttatus♀×Epinephelus polyphekadion♂)幼鱼血清生化指标、脂代谢相关基因的表达以及肝脏代谢组的影响,为水飞蓟素在杂交石斑鱼饲料中开发利用提供参考。【方法】取(24.06±0.15)g杂交石斑鱼幼鱼,分别投喂添加0、0.2、0.4和0.6 g/kg的水飞蓟素4种等氮等脂饲料(分别记为SL0、S1、S2和S3)56 d,测定石斑鱼的血清生化指标和脂代谢相关基因的表达,对肝脏进行代谢组分析。【结果】1)与对照(SL0组)相比,S1和S2组血清中甘油三酯的含量显著下降,S3组血清中总胆固醇、低密度脂蛋白胆固醇、谷草转氨酶和谷丙转氨酶的含量显著下降,S2组血清中总蛋白、白蛋白和高密度脂蛋白胆固醇的含量显著上升(P<0.05);2)与SL0组相比,S1、S2和S3组肝脏中hmgcr的表达水平显著下调以及pparγ的表达水平显著上调,S2组肝脏中pparα的表达水平显著上调(P<0.05);3)与SL0组相比,S1和S2组肌肉中pparγ的表达水平显著下调(P<0.05);4)与SL0组相比,在S3组肝脏代谢组中筛选出18种差异代谢物,其中共有15种差异代谢物下调,3种差异代谢物上调;谷胱甘肽代谢和鞘脂信号通路两条代谢通路被显著富集,5-羟脯氨酸、腺苷和牛磺鹅去氧胆酸等代谢物发生显著变化。【结论】饲料中添加0.6 g/kg的水飞蓟素可通过调节脂质代谢相关基因的表达抑制肝脏胆固醇的合成,调节代谢物的含量发挥抗氧化和免疫调节作用,从而降低杂交石斑鱼幼鱼的血脂水平,改善肝脏健康。

【Objective】To investigate the effects of dietary silymarin supplementation on serum biochemical parameters,lipid metabolism-related gene expression,and liver metabolome in juvenile hybrid grouper(Epinephelus fuscoguttatus♀×Epinephelus polyphekadion♂),and build a foundation for the development and utilization of silymarin in hybrid grouper feed.【Method】A total of 360 juvenile hybrid grouper(24.06±0.15 g)were selected and fed four isonitrogenous and isolipid diets supplemented with 0,0.2,0.4,and 0.6 g/kg of silymarin for 56 d,which were recorded as SL0,S1,S2,and S3 groups,respectively.The serum biochemical indices and the expression of genes related to lipid metabolism were measured in grouper,and liver metabolomic analysis was performed.【Result】1)Compared with the control group(SL0 group),the serum levels of triglycerides were significantly decreased in S1 and S2 groups,the serum levels of total cholesterol,low-density lipoprotein cholesterol,glutathione transaminase and glutamic acid transaminase were significantly decreased in S3 group,and the serum levels of total protein,albumin and high-density lipoprotein cholesterol were significantly increased in S2 group(P<0.05);2)Compared with the SL0 group,the expression levels of hmgcr were significantly downregulated as well as pparγwere significantly upregulated in the livers of S1,S2 and S3 groups,and the expression level of pparαwas significantly upregulated in the livers of S2 group(P<0.05);3)Compared to SL0 group,the expression levels of pparγwere significantly downregulated in the muscles of S1 and S2 groups(P<0.05);4)Compared to SL0 group,in the liver metabolome of S3 group,18 differential metabolites were screened,among which a total of 15 differential metabolites were down-regulated and 3 differential metabolites were up-regulated;glutathione metabolism and sphingolipid signaling pathways were significantly enriched,and metabolites such as 5-hydroxyproline,adenosine and taurodeoxycholic acid were significantly changed.【Conclusion】The addition of 0.6 g/kg of silymarin in the diet could inhibit the synthesis of liver cholesterol by regulating the expression of lipid metabolism-related genes,and regulate the content of metabolites to exert antioxidant and immunomodulatory effects,thereby reducing the blood lipid level of juvenile hybrid grouper and improving liver health.