The Effects Of Yeast Culture Against CCl_4-induced Liver Damage In Pseudobagrus Ussuriensis

In recent years,yeast culture as a microecological preparation could maintain intestinal health,improve fish and shrimp production performance and immune function,which has been widely recognized in the aquatic industry.However,there is no report that yeast culture could protect the hepatic damage.Previous studies in our laboratory have found that adding 0%,1%,2%,and 3%yeast culture to the diets of Pseudobagrus ussuriensis for 8 weeks,the significantly increased in growth performance and antioxidant ability was exhibited in the fish fed 2%yeast culture.Based on the previous experiments,the fish were randomly divided into three groups（Y0,Y0/CCl₄,Y2/CCl₄）with three replicates and 30 fish in each replicate at the present study.The Y0 and Y0/CCL₄groups were fed basal diet without yeast culture,and the Y2/CCl₄ group was fed diet with 2%yeast culture.After 8 weeks feeding,Y0 group was intraperitoneally injected olive oil with 0.05ml/15 g fish body weight and Y0/CCl₄ and Y2/CCl₄ intraperitoneally injected 30%CCl₄olive oil solution with 0.05ml/15g fish body weight for 48 hours.The aim of this study was to investigate the protective effect of yeast culture on hepatic oxidative injury and inflammation in Pseudobagrus ussuriensis exposed to CCl₄.The main research contents and results are as follows:（1）Effect of yeast culture on histological observation in liver of CCl₄-treated Pseudobagrus ussuriensis.Compared with Y0,the higher occurrences of the vacuolar degeneration,necrosis and nuclei shifting to the cellular periphery were detected in Y0/CCl₄ group.Lower occurrences of these histopathological symptoms were observed in the Y2/CCl₄ group compared with those fish in the Y0/CCl₄ group.（2）Effect of yeast culture on GPT and GOT activities in plasma of CCl₄-treated Pseudobagrus ussuriensisAfter treated with CCl₄ for 48 hours,the plasma activities of GOT（P>0.05）and GPT（P<0.05）in Y0/CCl₄ group was higher than that in the Y0 group,and GPT activity was significantly different;Compared with the Y0/CCl₄ group,the GOT and GPT activities in Y2/CCl₄ group were reduced,but GOT activity was significantly lower than that in Y0/CCl₄ group（P<0.05）.This result indicated that CCl₄ could cause hepatic damage and yeast culture could alleviate it.（3）Effect of yeast culture on antioxidant capacity in liver of CCl₄-treated Pseudobagrus ussuriensisAfter treated with CCl₄,the MDA content in Y0/CCl₄ group was significantly increased than Y0 group（P<0.05）.MDA content in Y2/CCl₄ was reduced than that in Y0/CCl₄ group,but there was no significantly different（P>0.05）;The determination of liver SOD activity showed that the SOD activity in Y0/CCl₄ group was significantly reduced than that in Y0 group（P<0.05）.But,the activity of SOD in Y2/CCl₄group with yeast culture was significantly higher than that in Y0/CCl₄group（P<0.05）;The CAT activity in Y0/CCl₄ group was significantly higher than that in Y0 group（P<0.05）.Compared with Y0/CCl₄ group,the activity of CAT in Y2/CCl₄ group was significantly increased（P<0.05）;There was no significant different in the GPX activity among three groups（P>0.05）.Those results showed that dietary yeast culture supplementation could alleviate Pseudobagrus ussuriensis liver damage induced by CCl₄ to a certain extent,which may be related to its functions of anti-stress ability and anti-lipid peroxidation.（4）Effect of yeast culture on immune ability of hepatic injury induced by CCl₄ in Pseudobagrus ussuriensisCompared with Y0 group,the lysozyme activity in Y0/CCl₄ group was significantly increased（P<0.05）,while the activity in Y2/CCl₄ group was significantly decreased than that in Y0/CCl₄ group（P<0.05）;Compared with the Y0 group,the Ig M（P<0.05）and ACH50（P>0.05）content in Y0/CCl₄group was decreased.But,compared with the Y0/CCl₄ group,the plasma ACH50 in Y2/CCl₄ group was significantly increased and Ig M content also increased with no significant difference.There were no significant differences in AKP activity among three groups（P>0.05）.（5）Effect of yeast culture on hepatic damage related gene expression in CCl₄-treated Pseudobagrus ussuriensisAfter treated with CCl₄,compared with the Y0 group,the expression levels of hepatic TLR2,My D88 NF-κβp65 gene in Y0/CCl₄ group were significantly increased（P<0.05）.Compared with the Y0/CCl₄ group,the decrease of TLR2,My D88 NF-κβ_p65was found in Y2/CCl₄ group,but hepatic NF-κβp65 gene in Y2/CCl₄ group was significantly reduced（P<0.05）;The expression levels of hepatic IL-8 and Hsp70 gene in Y0/CCl₄ group was significantly increased compared with the Y0group（P<0.05）.But,compared with the Y0/CCl₄ group,the hepatic IL-8 and Hsp70 gene in Y2/CCl₄ group was significantly decreased（P<0.05）.There were no significant differences in hepatic 1L-1βgene expression level was not significantly different among three groups（P>0.05）.In summary,the supplementation of 2%yeast culture could relieve the hepatic damage induced by CCl₄ and improve the immune inflammatory response and protect the liver from inhibiting lipid peroxidation.