Effects Of Baicalin Yeast Culture On Growth, Muscle Composition, Antioxidant And Immune Properties Of Grouper Saddlefish

The aim of this study was to study the effects of baicalin yeast culture(BYC)on growth performance,body mass index,muscle nutrient composition and evaluation,digestive enzyme activity,plasma biochemical index,non-specific immune capacity and antioxidant capacity of Epinephelus sellaceus,so as to explore the appropriate amount of baicalin yeast culture in feed.The results are as follows:Experiment 1:The actual content of baicalein in the yeast culture of baicalin was determined and the detection method was established.The results showed that the actual content of baicalein was 1.65mg/g(air-dry matter basis);Experiment 2:Four experimental diets were prepared containing 0%(Group A0control),0.2%(group A1),0.5%(group A2)and 1%(Group A3)yeast _aculture of baicalin,respectively.Experimental fish with a mean weight of 62.56 g(SD,0.55)were randomly divided into four groups(three replicates per group)and were fed experimental diets for 112 d.The results showed that:(1)the specific growth rate(SGR),weight gain rate(WGR)and feed intake(FI)of experimental animals increased first and then decreased with the increase of additive level,and reached the maximum value in 0.5%group(P<0.05);however,the above indexes in 1%group were lower than those in control group although the difference was not significan(P>0.05),and the optimal dosage was 0.5%.(2)the pepsin activity in the stomach of 0.5%group was the highest,which was significantly higher than that of control group(P<0.05);the trypsin in the 0.5%group was significantly higher than that in control group(P<0.05);the lipase(LPS)and amylase(AMS)increased first and then decreased with the increase of the added level,however,the difference was not significant(P>0.05).(3)the content of crude protein(CP)in muscle of 0.5%group was significantly higher than that of control group(P<0.05);there was no significant difference in amino acid composition of muscle among all groups(P>0.05);no significant differences were observed in muscle AAS and CS among all groups(P>0.05).The results showed that appropriate amount of baicalin yeast culture(BYC)could improve the growth performance and protease activity of Epinephelus sellaceus,and increase the crude protein content of muscle,but excessive baicalin yeast culture would show a growth inhibition tendency.The results showed that:(1)the activities of superoxide dismutase(SOD),glutathione peroxidase(GSH PX),catalase(CAT)and total antioxidant capacity(T-AOC)in liver,intestine and plasma of experimental fish increased first and then decreased slightly,and reached the maximum value in 0.5%group,which was significantly higher than that in control group(P<0.05);malondialdehyde(MDA)decreased first and then stabilized,and reached the minimum value in the 0.5%group,which was significantly lower than that in the control group(P<0.05);(2)the contents of total protein(TP)and albumin(ALB)increased at first and then decreased and reached highest value at 0.5%;the plasma alanine aminotransferase(AST)and glutamic oxaloacetic transaminase(ALT)showed a downward trend(P<0.05);(3)The activities of acid phosphatase(ACP),alkaline phosphatase(AKP)and lysozyme(LZM)in plasma,liver and intestines showed an upward trend,and reached the maximum in 0.5%or 1%group,which was significantly higher than that in control group(P<0.05).The results showed that baicalin yeast culture could significantly improve the antioxidant capacity and non-specific immunity of Epinephelus sellaceus,and alleviate the liver burden to a certain extent.In conclusion,baicalin yeast culture can improve the growth performance,digestive enzyme activity,muscle protein content,antioxidant capacity and immune capacity of Epinephelus sellaceus.The optimal addition level of baicalin yeast culture was 0.5%.