Effects Of Ethanol Extract From Chlorella Sp. On Growth Performance And Mechanism Of Juvenile Lateolabrax Japonicas

With Lateolabrax japonicus as objects,this thesis was conducted to investigate the effects of ethanol extract from Chlorella sp.on growth performance?body composition?serum biochemical indices?digestive enzyme activities?immunity function?osxidation resistance and intestinal structure of juvenile Lateolabrax japonicas,carrying on preliminary discussion and revealing ethanol extract from Chlorella sp.on mechanism of growth performance of different specifications of juvenile Lateolabrax japonicas by in-door breeding with the recycling of the water and resisted Aeromonas hydrophila experiments.The contents and results are as follows:1 Effects of ethanol extract from Chlorella sp.on growth performance ? body composition of juvenile Lateolabrax japonicas.Experiment?: Four hundreds and eighty L.japonicas(initial body weight 35.06±0.06 g)were randomly divided into 6 dietary treatments,each treatment had 4 replicates and each replicate had 20 fish.Each treatment was fed diets supplemented with 0,100 mg/kg,300 mg/kg,500 mg/kg,1000 mg/kg and 1500 mg/kg ethanol extract from Chlorella vulgaris lasted for 42 days,respectively.Experiment ?: Seven hundreds and twenty L.japonicas(initial body weight 3.06±0.01 g)were randomly divided into 6 dietary treatments,each treatment had 4 replicates and each replicate had 30 fish.Each treatment was fed diets supplemented with 0,20 mg/kg,50 mg/kg,75 mg/kg,100 mg/kg and 200 mg/kg ethanol extract from Chlorella vulgaris lasted for 56 days,respectively.The results showed that survival rate(SR)had no significant affected by ethanol extract from Chlorella vulgaris level,SR of each group all higher than 97.5%(P>0.05).Specific growth rate(SGR)was increased during experiment?,while experiment ? had decreased,but had no significant affected by ethanol extract from Chlorella vulgaris(P>0.05).Protein efficiency ratio(PER)were increased with ethanol extract from Chlorella vulgaris,and 100 mg/kg group were significantly higher than control in experiment ?(P<0.05).Feed coefficient(FC)decreased with ethanol extract from Chlorella vulgaris(P>0.05).Viscerosomatic index(VSI)and intraperitoneal fat index(IPF)decreased during experiment ?(P>0.05).The crude protein(CP)and the crude fat(CF)of the body had no significantly difference(P>0.05);but moisture of the body had decreased,and 1500 mg/kg group significantly lower than control(P<0.05).With ethanol extract from Chlorella sp.,monounsaturated fatty acids(MUFA)in muscles of juvenile Lateolabrax japonicas had obvious influence.The content of C16:1 at 25 mg/kg?75 mg/kg ?200 mg/kg group significantly lower than control,and the content of C18:1 at 75 mg/kg ?200 mg/kg group significantly lower than control(P<0.05).ethanol extract from Chlorella sp.can affect polyunsaturated fatty acid(PUFA)in muscles of juvenile Lateolabrax japonicas,the content of C18:3 and C22:6(DHA)were rasing,but C20:5(EPA)was downswing(P>0.05).2 Effects of ethanol extract from Chlorella sp.on serum biochemical indices?digestive enzyme activities of juvenile Lateolabrax japonicas.Ethanol extract from Chlorella sp.can rasing the content of glucose(GUL)(P>0.05).Experiment?: the total protein(TP),urea nitrogen(UREA),total cholesterol(CHOL),triglyceride(TG)and low density lipoprotein(LDL)all were decreased in serum(P>0.05);aspartate aminotransferase(AST)of 300 mg/kg higher than control significnatly(P<0.05).Experiment ? : globulin(GLO)increased at first and then decreased with ethanol extract from Chlorella sp.rasing,100mg/kg group had supreme content,but had no significantly diffentence(P>0.05).Ethanol extract from Chlorella sp.could obviously affect the digestive enzyme activities of juvenile Lateolabrax japonicas.With raising supplementation of ethanol extract from Chlorella sp.,protease activity in the intestine decreased,and trial group(except 300 mg/kg)in experiment?significantly decreased(P<0.05);lipase activity had increased within 300 mg/kg,then decreased over 300 mg/kg,but all had no significantly differences(P>0.05);amylase activity significantly decreased compared with control in experiment?(P<0.05).Ethanol extract from Chlorella sp.could improve the amylase activity of different specifications of juvenile Lateolabrax japonicas in liver(P>0.05);lipase activity significantly higher than control with 100 mg/kg at experiment ?(P<0.05);amylase activity of 1000 mg/kg had significant difference with others at experiment?(P<0.05).3 Effects of ethanol extract from Chlorella sp.on immunity function?oxidation resistance of juvenile Lateolabrax japonicas.The content of lysozyme,alkaline phosphatase,acid phosphatase,nitric oxide,glutathione peroxidase and malondialdehyde in serum of juvenile Lateolabrax japonicas had no significantly differences(P>0.05).Experiment?:The catalase of 1500 mg/kg significantly higher than control in serum(P<0.05);100 mg/kg group had supreme content of total antioxidant capacity than control in serum at experiment ?(P<0.05);the superoxide dismutase in serum of 100 mg/kg significantly higher than control at experiment?(P<0.05).Ethanol extract from Chlorella sp.had significantly effect on catalase,superoxide dismutase,glutathione peroxidase and malondialdehyde in liver(P>0.05).Ethanol extract from Chlorella sp.could reduce accumulative mortality rate of juvenile Lateolabrax japonicas infected with aeromonas hydrophila after 96 h(P>0.05).4 Effects of ethanol extract from Chlorella sp.on intestinal structure of juvenile Lateolabrax japonicas.500 mg/kg of number of folds significantly higher than others(except 300 mg/kg group)at experiment ?(P<0.05).The muscle thickness of juvenile Lateolabrax japonicas had reduced with ethanol extract from Chlorella sp.added(P>0.05).The folds height had decreased at experiment?then it increased at experiment ?,but all had no significantly difference(P>0.05).In conclusion,ethanol extract from Chlorella sp.could improve the growth performance of of juvenile Lateolabrax japonicas due to it can enhance protein efficiency ratio,content of unsaturated fatty acid in muscle and immunity and anti-oxydation ability,then it can reduced feed coefficient.Different specifications juvenile Lateolabrax japonicas had different expression with ethanol extract from Chlorella sp..For growth and the cost for additions,ethanol extract from Chlorella sp.optimum adding amount was 300 mg/kg(initial body weight 35.06±0.06 g)and when initial body weight was 3.06±0.01 g,ethanol extract from Chlorella sp.optimum adding amount was 100 mg/kg.