Study On The Dietary Pantothenic Acid And Myo-inositol Requirements Of Juvenile Turbot(Scophthalmus Maximus L.)

Part1:An 80d feeding trial was conducted to investigate the dietary requirement of pantothenic acid for juvenile turbot.Sixisoenergetic and isonitrogenous diets were formulated using the fish meal and casein as protein source.Calcium D-pantothenic was supplemented to the basal diet at a rate of 0、5、10、20、40、80 mg/kg.The analyzed values of dietary pantothenic acid are 6.24、10.64、15.02、23.81、41.40、76.57 mg/kg,respectively.Each diets was randomly assigned assigned to 3 replicates of 30 juvenile turbot(weight approximately 24.73±0.1 g).The results showed that:1)pantothenic acid had no significant effect on the survival rate(SR)of juvenile turbot(P>0.05),the weight growth rate(WGR)and the specific growth rate(SGR)increased with increasing levels of pantothenic acid from 10.64-76.57 mg/kg(P<0.05),when the dietary pantothenic acid content more than 23.81 mg/kg,hepatomatic index was significantly decreased(P<0.05).2)With an increase of dietary pantothenic acid,the crude protein,crude lipid of whole body and the crude protein of muscle initially increased and then decreased,crude lipid content of liver decreased with dietary pantothenic acid(P<0.05).3)With an increase of dietary pantothenic acid level,activities of intestinal digestive enzyme、Na~+,K~+-ATPase and hepatic cholinesterase(ChE)initially increasing and then decreased,intestinal creatine kinase(CK)activity increased significantly from10.64-76.57 mg/kg(P<0.05).4)Hepatic and serum catalase activities(CAT),superoxide dismutase(SOD)were significantly lower in control group than in the groups with calcium pantothenic acid enriched diets(P<0.05).turbot fed 6.24 mg/kg pantothenic acid diet had higher malondialdehyde content in serum than those fed the other diets(P<0.05).5)Fatty acid synthetase(FAS)expressions increased with increasing levels of pantothenic acid,then decreased.The expression of the lipoprotein lipase(LPL)was significantly up-regulated in liver with increasing levels of pantothenic acid(P<0.05).In conclusion,appropriate dietary pantothenic acid improved significantly intestinal digestion and absorption capacity,thus improve the body’s nonspecific immunity,and increase the expression of fat-related genes,then promote the growth performance and body composition of juvenile turbot.Based on the broken-lineregression analysis of WGR and FER,the requirements range of pantothenic acid in juvenile turbot with the intial mass of 24.73g is 13.45-16.08 mg/kg.Part2:An 80-day growth experiment was conducted to investigate the dietary myo-inositol requirement of juvenile turbot(Scophthalmus maximus).The fish were randomly divided into six groups:a control group was fed with basal diet(319.00mg/kg),and five treatment groups fed with basal diet supplemented with graded myo-inositol levels(511.00、703.00、1087.00、1855.00、3391.00 mg/kg of dry diet respectively).Each diet(30 fish)was fed to triplicate groups of juvenile turbot with initial average body weight(24.73±0.10)g.The results showed that:1)weight gain rate(WGR)and specific growth rate(SGR)of each experimental group were significantly higher than those of the control(P<0.05);feed efficiency ratio(FER)increased significantly when myo-inositol content reached 703.00 mg/kg(P<0.05).2)The dietary myo-inositol significantly reduce the crude lipid content of liver(P<0.05).and the lipid content of the whole fish in the 1087.00-3391.00 mg/kg group is significantly lower than the other three groups,wherase crude lipid in muscle was significantly enhanced compared with the control(P<0.05).3)turbot fed 1087.00 mg/kg myo-inositol diet had higher lipase activity than those fed the other diets(P<0.05),which was 60%higher than that of the control group.(P<0.05).4)With increasing dietary myo-inositol level,the activity superoxide dismutase(SOD)in serum firstly deceased and then increased,when the myo-inositol content reached 703.00 mg/kg,the serum malondialdehyde(MDA)content decreased significantly(P<0.05),and the 3391.00 mg/kg group was 44%lower than the control group.5)Fed the 703.00 mg/kg and 1087.00 mg/kg diet showed significantly increased cholesterol(TCHO)and triglyceride in the serum(P<0.05).6)Significantly higher content of saturated fatty acids(SFA)in the liver was obtained in fish fed the 1087.00 mg/kg diets than other diets(P<0.05).With the increase of myo-inositol content,the content of polyunsaturated fatty acids in liver and muscle increased significantly(P<0.05),and the maximum appeared in 3391.00 mg/kg and1087.00 mg/kg groups,respectively.The findings suggest that the addition of proper content of myo-inositol in feed can improve the growth performance,digestion and antioxidant capacity of juvenile turbot,regulate blood lipid content,and improve fatty acid composition.Based on the broken-lineregression analysis of WGR and FER,the requirements range of myo-inositol in juvenile turbot with the initial mass of 24.73g is622.93-991.00 mg/kg.