Hepatoprotective Effects Of Berberine On Fatty Liver Injury In Tilapia(Oreochromis Mossambicus)

In recent years,with the development of aquaculture and the excessive use of high-protein and high-fat diets,various fish such as Cyprinus carpio,Carassius auratus,Oreochromis mossambicus and Megalobrama amblycephala have begun to develop fatty liver injury and other diseases,which seriously affects the metabolic function and disease resistance of fish and restricts the development of modern aquaculture.Therefore,it is of great significance to explore the mechanism of fatty liver injury and screen liver protection drugs for aquatic animals and the stable development of the industry.In this study,we established a fatty liver injury model of tilapia by feeding high-fat diets and investigated the protective effect of berberine on fatty liver injury in tilapia.The main research contents and results are as follows:1 Effect of fat levels on the blood lipids,liver function and expression of lipid metabolism related genes in tilapia:A model of fatty liver injury was established by using feeds with different fat levels(6%,11%,21%).The change of blood lipids content,liver function parameters and lipids metabolism related genes in the fish were measured.The results showed that the levels of Triglyceride,Total Cholesterol,Low density lipoprotein cholesterol,Glutamate-Oxaloacetate Transaminase and Glutamate-Pyruvic Transaminase were significantly increased(P<0.05)in the 21%fat level group when compared with the 6%fat level group after 8 weeks feeding,which indicated high blood lipid content and liver damage.Simultaneously,the expressions of β-oxidation related genes(Peroxisome Proliferators-Activated Receptor α,Acyl-Coa Oxidase I and Carnitine Palmitoyltransferase I)in the liver were significantly decreased after 8 weeks in high fatty diet group(P<0.05),while the expression of fat synthesis genes(Sterol Regulatory Element Binding Proteins-1C,Fatty Acid Synthase and Acetyl CoA carboxylase I)showed an irregularity change among different groups.The results displayed that high-fat diets led to the lipid metabolism disorders in tilapia.2 The effect of fat levels on oxidative stress and inflammatory factor expression in tilapia:After 8 weeks of experiment,the changes of Malondialdehyde,Superoxide Dismutase,Total antioxidant capability,Glutathione and Catalase levels were observed in tilapia.The results showed that,compared with the 6%fat level group,the Malondialdehyde content in the serum and liver of the 21%fat level group was significantly increased(P<0.05),while the Superoxide Dismutase,Total antioxidant capability,Glutathione and Catalase were reduced at different extents.It indicates that the high-fat diet can cause lipid peroxidation and the decrease of antioxidant capacity in the liver of tilapia.The expression of pro-inflammatory cytokines(Tumor Necrosis Factor-α,Interleukin-1β and Rel-B)in the liver of 21%fat level group were significantly higher than those in the 6%fat level group(P<0.05),indicating that the inflammatory response was an important component of fatty liver injury in tilapia.3 Protective effects of berberine on fatty liver injury induced by high-fat diets in tilapia:The fish were divided into 5 groups,blank group(6%fat level)and high fat group(21%fat level),low dose berberine group(50mg/kg),medium dose berberine group(100mg/kg)and high dose berberine group(200mg/kg).After 8 weeks feeding,changes in physiological and biochemical indexes,fat metabolism and expression of inflammation-related genes in tilapia were analysed.The results showed that berberine could effectively reduce the contents of serum Triglyceride,Total Cholesterol,Low density lipoprotein cholesterol,Glutamate-Oxaloacetate Transaminase and Glutamate-Pyruvic Transaminase in tilapia and alleviate the liver injury compared with the high-fat group.Under the intervention of berberine,the Malondialdehyde content in the liver of berberine treatments were significantly decreased(P<0.05),and the levels of Superoxide Dismutase,Total antioxidant capability,Glutathione and Catalase were significantly increased to some extent,indicating the degree of peroxidation of the body was alleviated and the antioxidant capacity was enhanced.Simultaneously,berberine can increase effectively the expression of Peroxisome Proliferators-Activated Receptor α,Acyl-Coa Oxidase I and Carnitine Palmitoyltransferase I genes and reduce significantly the expression of proinflammatory gene of Tumor Necrosis Factor-α,Interleukin-1β and Rel-B(P<0.05)in high fatty diet group.The results indicated that berberine has a protective effect on the liver of tilapia,and this protective effect is related to its ability to resist oxidation,regulation of fat metabolism balance and alleviation of inflammatory response.Therefore,berberine can be used as a hepatoprotective agent to relieve fatty liver injury in fish.