Ameliorative Effects Of Ginkgo Biloba Extract On Oxidative Stress In Cyprinus Carpio

In aquaculture,fish inevitably suffers from a variety of stressors,leading to stress response,especially oxidative stress.In fish,oxidative stress is related to the occurrence and progress of many diseases,but it is lacking direct evidences regarding pathogenic mechanism of oxidative stress.Therefore,the aim of this study was to investigate the antioxidative status and immune responses in common carp（Cyprinus carpio）under oxidative stress.In this study,hydrogen peroxide（H₂O₂）was used to establish an oxidative stress model in Cyprinus carpio.Further,we investigated the protective effects of ginkgo bioba extract（GBE）on oxidative stress in Cyprinus carpio.The main research contents and results includes four experiments:1.Antioxidative status in Cyprinus carpio under oxidative stress:The fish were exposed to four concentrations of H₂O₂（0,0.25,0.50 and 1.00 mmol/L）for 14 days.After14 days of exposure,we collected the blood and liver,gill,intestinal,and muscle tissues to determine biochemical parameters and genes expression.The data showed that the levels of cortisol,triglyceride（TG）and lactic acid（LA）in H₂O₂treatments were significantly higher than those of the control group.The antioxidative data showed that H₂O₂exposure suppressed antioxidative ability in serum,liver,intestinal and muscle,but enhanced antioxidative ability in gills.Meanwhile,H₂O₂exposure markedly enhanced the levels of malondialdehyde（MDA）in liver,gill,intestinal,and muscle tissues.The genes expression data showed that H₂O₂exposure promoted the oxidative stress-related genes including nuclear factor erythroid 2-related factor 2（nrf2）,glutathione-S-transferase（gstα）,superoxide dismutase（sod）,catalase（cat）and glutathione peroxidase（gpx1）in the majority of tested tissues.However,the m RNA level of heme oxygenase（ho-1）was downregulated in the majority of tested tissues.2.Immune and inflammatory response in Cyprinus carpio under oxidative stress:The aim of the study was to investigate the immune and inflammatory responses to long-term H₂O₂exposure in liver,intestinal and muscle tissues of Cyprinus carpio.The data showed that H₂O₂exposure induced a significant immune response,with alterations in the levels of immune parameters including alkaline phosphatase（AKP）,acid phosphatase（ACP）,Lysozyme（LZM）,complement 3（C3）,heat shock protein 90（HSP90）and heat shock protein 70（HSP70）in different tissues.After H₂O₂exposure,the immune and inflammatory response was evoked,which was associated with activation of Toll-like receptors（TLRs）and nuclear factor kappa B（NF-κB）in the majority of tested tissues.Moreover,immune and inflammatory responses to H₂O₂exposure were in a dose-dependent and tissue-specific manner.3.Effect of GBE on growth performance,antioxidant function and immune-related genes expression of Cyprinus carpio:The aim of this study was to investigate the effects of GBE on the growth performance,serum biochemical indices,antioxidative status,CYP450 and immune-related gene expressions of Cyprinus carpio.The fish were fed a basal diet supplemented with GBE at concentrations of 0 g/kg（control）,0.5 g/kg,1.0 g/kg,and 5.0 g/kg for 60 days.Subsequently,blood,liver,intestine,gill,and muscle tissues were collected to evaluate biochemical parameters and gene expressions.The results indicated that the different concentrations of dietary GBE did not improve the growth performance and feed coefficient（P>0.05）of carp.Serum concentrations of total cholesterol（TC）,triglycerides（TG）,alanine aminotransferase（ALT）,and aspartate aminotransferase（AST）did not differ significantly between treatments and controls（P>0.05）,although GBE treatments significantly increased the serum total protein（TP）content and decreased Glu and cortisol levels.The antioxidant indices showed that dietary GBE could significantly increase the levels of superoxide dismutase（SOD）,catalase（CAT）,total antioxidant capacity（T-AOC）,and glutathione（GSH）in the liver（P<0.05）.Furthermore,the T-AOC in the intestines and gills was significantly higher in the GBE treatment groups than that in the control group,and GSH was significantly higher in the gills of carp in the 5.0 g/kg GBE treatment than that in the other groups.Moreover,the gene expression data indicate that dietary GBE up-regulated the transcription of cytochrome p450（cyp3a）and down-regulated the transcription of cyp1a and cyp1b in the liver and intestines of carp.Additionally,immune-related genes（c3 and c-lyz）in the livers and intestines of carp in the 1.0 g/kg and 5.0 g/kg GBE groups were significantly up-regulated.In conclusion,dietary GBE did not improve the growth performance and feed coefficients in carp;however,it reduced physiological stress,improved antioxidant ability,and increased expression of immune-related genes.Based on the results of our study,we recommend supplementing common carp with 1.0 g/kg of dietary GBE.4.Ameliorative effects of GBE on oxidative stress in Cyprinus carpio:Based on the above experimental results,to investigate the effects of GBE on the level of immune and inflammatory responses to long-term H₂O₂exposure in different tissues of Cyprinus carpio.Tree hundred fishes were randomly assigned to the following five groups,including normal control groups,H₂O₂groups,and three GBE groups（0.5,1.0 and 5.0 g/kg）.After feeding for 60 days,common carp were exposed to 1.0 mmol/L H₂O₂for 14 days.Subsequently,blood,liver,intestine,gill,and muscle tissues were collected to evaluate biochemical parameters and gene expressions.Compared with the H₂O₂group,adding 1.0～5.0 g/kg GBE in diets could significantly suppressed the activity of TG,TP,LA and cortisol in serum,and significantly improved the levels of T-AOC,SOD,CAT,GSH in serum,liver and intestinal tissues,and significantly reduce the level of MDA in the majority of tested tissues.Gene expression results showed that H₂O₂exposure could significantly increased the expression levels of immune-related genes（c3,c-lyz and hsp70）in liver,intestinal and muscle tissues than the normal control group,but significantly decreased in gill tissues.Moreover,after feeding for 60 days,c-lyz,c3 and hsp70 highly expressed in all tested tissues than the H₂O₂group.Moreover,immune-relate gene expression in 1.0 g/kg GBE group were in a dose-dependent and tissue-specific manner.Overall results suggested that dietary with GBE could strengthened anti-stress,improved antioxidant ability and increased immune-related（c3,c-lyz and hsp70）genes expression.Therefore,GBE can be used as a potential anti-oxidative stress additive in aquaculture.