Effects Of Reduced Glutathione On Growth,Antioxidant Capacity And Serum Biochemical Indices Of Scophthalmus Maximus

The present study was to investigate the effects of the amount of the basal diet supplementary with GSH on the growth,antioxidant capacity and serum biochemical parameters of the same and different fat sources,and determined the appropriate level of dietary GSH of turbot.The results could provide the theoretical basis for the turbot healthy farming and the application of reduced glutathione in turbot feed.The results of the study are presented as follows:1.Effects of reduced glutathione on growth,antioxidant capacity,serum biochemicalindices of Scophthalmus maximus.The turbot with initial weight of(23.08±0.09)g were fed the basal diet supplemented with 0,100,200,400,600 mg/kg reduced glutathione(GSH)respectively.A 56-day feeding trial was conducted to evaluate the growth performance,physical indices,body composition,feed utilization the antioxidant capacity and the serum biochemical indices of turbot.The weight gain rate and the specific growth rate of the turbot at 200 mg/kg dietary GSH group were significantly higher than the other groups(P<0.05).The dietary GSH had no significant differences on the protein efficiency ratio,condition factor,visceral-body index and the hepatosomatic index(P>0.05),the hepatosomatic index of turobt showed a trend of increasing at first and then decreasing,reaching the highest at the 400 mg/kg dietary GSH group.The dietary GSH had no significant differences on the food intake rate,food conversion ratio,protein efficiency ratio of turbot(P>0.05).At the 200 mg/kg and 400 mg/kg dietary GSH group,the crude protein of whole-fish were significantly higher than the control group(P<0.05),the dietary GSH had no significant differences on the moisture,crude lipid and ash of whole-fish(P>0.05).The dietary GSH had no significant differences on the feeding rate,feed conversion rate,dry matter digestibility and protein digestibility.The food conversion ratio of turobt showed a trend of decreasing at first and then increasing,reaching the lowest at the 200 mg/kg dietary GSH group.The dietary GSH had no significant differences on the peptic activity,amylase activity and lipase activity.All of three digestive enzyme activitiesof turobt showed a trend of increasing at first and then decreasing,reaching the highest at the 200 mg/kg dietary GSH group.The dietary GSH had no significant differences on the malondialdehyde(MDA),total antioxidant capacity(T-AOC),Superoxide Dismutase(SOD)activity and Glutathione peroxidase(GSH-PX)activity of the liver of turbot(P>0.05).With the increase of the dietary GSH,the MDA in the liver of turbot was highest at the control group,and was lowest at the 200 mg/kg dietary GSH group.All theT-AOC,SOD activity and GSH-PX activity of the liver of turbot showed a trend of increasing at first and then decreasing,reaching the highest at the 200 mg/kg dietary GSH group.At the 200 mg/kg and 400 mg/kg dietary GSH group,the GSH of the liver of turbot was significantly higher than the control group(P<0.05).At the 200 mg/kg dietary GSH group,the Glutathione S-transferases(GST)activity and the glutathione reductase(GR)activity of the liver of turbot was significantly lower than the control group(P<0.05).According to the regression analysis,the appropriate level of dietary GSH was 189.70 mg/kg.The dietary GSH had no significant differences on the alanine transaminase(ALT),aspartate aminotransferase(AST),alkaline phosphatase(ALP),Total Protein(TP),Blood glucose(GLU),Triglyceride(TG)and total cholesterol(TC)of turbot(P>0.05).In summary,the basal diet supplementary with GSH could promote the growth,improve the protein content of whole fish,and there was no negative impact on health and nutrition levels of turbot with appropriate level of dietary GSH,according to the regression analysis,the appropriate level of dietary GSH was 189.70 mg/kg.2.Effects of dietary lipid source and GSH on growth,antioxidant capacity,serum biochemical indices of Scophthalmus maximus.The turbot with initial weight of(23.08±0.09)g were fed the basal diet supplemented with F0(100% fish oil,0 mg/kg GSH),F200(100% fish oil,200 mg/kg GSH),F400(100% fish oil,400 mg/kg GSH),SF200(50% fish oil,50% Soybean oil,200 mg/kg GSH),SF400(50% fish oil,50% Soybean oil,400 mg/kg GSH)respectively.A 56-day feeding trial was conducted to evaluate the growth performance,physical indices,body composition,feed utilization the antioxidant capacity and the serum biochemical indices of turbot.At the SF200 group,the weight gain rate and the specific growth rate were significantly higher than the control group(P<0.05),there were no significant differences among the other groups.The weight gain rate and the specific growth rate of the SF200 and SF400 groups were higher than that of the whole fish oil groups,and there was no significant difference(P>0.05).The protein efficiency ratio of the SF200 group was significantly higher than the other groups(P<0.05).The dietary GSH had no significant differences on condition factor,visceral-body index and the hepatosomatic index(P>0.05),the visceral-body index was lowest at the SF200 group and the hepatosomatic index was lowest at the F400 test group.There were no significant differences on the crude lipid and ash of whole-fish(P>0.05).The moisture of the SF200 and SF400 groups were significantly higher than the control group.At the SF200 group,the crude protein of whole-fish were significantly higher than the other groups(P<0.05).The dietary lipid source and GSH had no significant differences on the feeding rate,feed conversion rate,dry matter digestibility and protein digestibility,the feed conversion rate was lowest at the SF200 group.There were no significant differences on the peptic activity,amylase activity and lipase activity,the SF200 and SF400 group were higher than the control group,and MDAwas lowest at the SF200 group.The dietary lipid source and GSH had no significant differences on the MDA,T-AOC of the liver of turbot(P>0.05).At the F200 and SF400 group,the GSH-PX activity of the liver of turbot were significantly higher than the other groups(P<0.05),the GST activity of the liver of turbot were significantly lower than the other groups(P<0.05).The GST activity of the liver of each experimental group was lower than that of the control group,but the difference was not significant(P>0.05).The dietary lipid source and GSH had no significant differences on the ALT,AST,ALP,TP,GLU,TG and TC of turbot(P>0.05).In summary,it indicates that 50% soybean oil in the turbot feed replaces fish oil,and adding appropriate amount of reduced glutathione has no negative impact on the health and nutrition level of turbot,and can ensure the growth performance of turbot,with good disease resistance and anti-stress ability to save costs and obtain maximum economic benefits.