Effects Of Phellodendri Chinensis Cortex And Berberine On Fatty Liver Of Epinephelus Fuscoguttatus Induced By High Fat

Long-term intake of high-fat feed often leads to excessive fat deposition and induces fatty liver in fish.Phellodendri Chinensis Cortex(PCC)and its alkaloid Berberine(BBR)have shown lipid-lowering effects in some mammals and fishes,but they have not yet been studied in grouper.In this study,a fatty liver model of Epinephelus fuscoguttatus was first established through high-fat diet induction,then a feeding trial of E.fuscoguttatus fed with/without PCC and BBR supplementation in high fat diet was conducted to evaluate their lipid-lowering effects,and the mechanism of PCC/BBR actions were studied via transcriptome sequencing analysis.Results are as follows:1.Establishing a E.fuscoguttatus fatty liver model: Three high-fat diet groups with lipid contents of 12%(HFD1),16%(HFD2)or 20%(HFD3)and a control group with a lipid content of 8% were set up.E.fuscoguttatus were fed different diets for 4 weeks.The results showed that: compared with the control group,the fatness(CF)and liver-to-body ratio(HSI)of the three high-fat diet groups were increased,but the differences were not significant(P>0.05).For fishes in HFD3,the weight gain rate(WGR)and specific growth rate(SGR)increased significantly(P<0.05);the livers significantly whitened,grew fragile,the cell structure injury relieved significantly and the liver cells were filled with large numbers of lipid droplets;triacylglycerol(TG),total cholesterol(T-CHO),Low-density lipoprotein cholesterol(LDL-C),alanine aminotransferase(ALT),aspartate aminotransferase(AST),superoxide dismutase(SOD),catalase(CAT),and malondialdehyde(MDA)levels for serum were significantly increased(P<0.05);high-density lipoprotein cholesterol(HDL-C)was significantly reduced(P<0.05).All above results indicated that E.fuscoguttatus fed with 20% lipid content diet(HFD3)had developed nutritional fatty liver with typical pathological symptoms.2.Evaluating the lipid-lowing effects of PCC and BBR in high-fat diet fish.Three experimental groups and a control group were set up: High-fat diet model group(HFD)were fed with a lipid content of 20% high-fat diet;high-fat diet PCC group(HFDP)were fed with a lipid content of 20% high-fat diet and 10g/kg PCC;high-fat diet BBR group(HFDB)were fed with a lipid content of 20% high-fat diet and 50 mg/kg BBR;and the control group(C)were fed with a lipid content of 8% basal diet.Samples were collected after feeding for 4 weeks,6 weeks,and 8 weeks,respectively.The results showed that,at 6weeks compared with the fatty liver model(HFD)group,fishes in HFDP and HFDB group showed increased WGR and SGR(P>0.05),significantly decreased CF(P<0.05),decreased HSI(P>0.05),and significantly alleviated liver whitening,brittleness,cell structure injury and fat infiltration which were caused by high-fat diet.PCC significantly reduced the TG,T-CHO,LDL-C,HDL-C,AST,ALT,CAT,SOD and MDA levels in the serum of HFD E.fuscoguttatus(P<0.05);BBR also reduced all above 10 serum indicators in HFD E.fuscoguttatus(P<0.05),except that the decrease of T-CHO,ALT and CAT were not significant(P>0.05).The above experimental results showed that when fed for 6 weeks,PCC and BBR can significantly improve the growth performance,reduce the serum lipid level,alleviate liver injury,and improve antioxidant capacity of E.fuscoguttatus on a high-fat diet.3.In order to explore the mechanism of PCC and BBR action on the immunity and lipid metabolism regulation in fatty liver model grouper,the liver and intestinal tissues of E.fuscoguttatus groups(HFD,HFDP,HFDB,C)at 6 weeks were analyzed by transcriptome sequencing.The results showed that in the liver,HFD vs C,HFDP vs HFD,HFDB vs HFD obtained 1650,1828,1211 differentially expressed genes(DEGs),respectively,which were mainly enriched in multiple immune-related pathways,such as the Staphylococcus aureus infection pathway.The DEGs of HFD vs C were significantly enriched in lipid metabolism-related pathways such as PPAR signaling pathway,Cholesterol metabolism pathway,et al.In the intestine,HFD vs C,HFDP vs HFD,HFDB vs HFD obtained 1574,2081,and 1840 DEGs,respectively.These DEGs were significantly enriched in multiple immune-related pathways,energy metabolism pathways and lipid metabolism-related pathways: HFD vs C had DEGs significantly enriched in multiple immune-related pathways(such as the Complement and coagulation cascades pathway)and lipid metabolism-related pathways(such as PPAR signaling pathway);HFDP vs HFD DEGs were significantly enriched in energy/lipid metabolism pathways such as the Pancreatic secretion pathway,Fat digestion and absorption pathway,Cholesterol metabolism pathway and so on;HFDB vs HFD DEGs were also significantly enriched in energy/lipid metabolism pathways such as Thermogenesis and non-alcoholic fatty liver(NAFLD),Steroid biosynthesis,Fat digestion and absorption,Cholesterol metabolism and so on.The above experimental results show that high-fat feed can regulate the lipid metabolism of E.fuscoguttatus through PPAR signaling pathway,Cholesterol metabolism pathway,Fat digestion and absorption pathway,NAFLD pathway,Steroid biosynthesis pathway,Fat digestion and absorption pathway,et al.PCC and BBR play a role in regulating the lipid metabolism of E.fuscoguttatus.The lipid metabolism regulation action of PCC and BBR on E.fuscoguttatus with high-fat diet was mainly in the intestine,while the immune-regulatory action of PCC and BBR on E.fuscoguttatus with high-fat diet was in both the intestine and the liver.