| 1.Effects of different lipid sources on growth performance,antioxidant enzyme activity and serum metabonomics of juvenile Chinese mitten crab,Eriocheir sinensis.The variation of metabolic mechanism for juvenile crabs with lipid sources rich in PA,OA,LA and LNA was not clear.Four purified diets with palm oil(rich in palmitic acid,PA),olive oil(rich in oleic acid,OA),safflower oil(rich in linoleic acid,LA)and perilla oil(rich in linolenic acid,LNA)as lipid sources at 6% dietary lipid level were conducted as before.Each diet was fed to E.sinensis 5.92 ± 0.08 g in six replicates for 8 weeks.The serum of the juvenile crabs was analyzed by GC-MS metabolomics.There was no significant difference for survival and weight gain of crabs between the four groups.The content of TG in hepatopancreas of crabs fed OA was significantly lower than that in the other three groups(P<0.05).The content of glycogen in hepatopancreas of crabs was highest for LNA group(P<0.05).The content of glucose and free fatty acids in serum were highest in LNA group(P<0.05).GC-MS analysis showed that up to 17 significant different metabolites(more than other groups)were identified between OA and LNA group.Only one metabolites content in the OA group decreased,the rest were all increased.Most of the significant different metabolites involved in energy metabolism pathways such as glycolysis,the Krebs cycle,and pentose-phophate pathway of energy metabolism pathways.There were only 4 significant different metabolites between LA and LNA group,and all of them were increased in the LA group.The results showed that the excessive accumulation of TG in hepatopancreas of crab will cause peroxidation damage for LNA group.Compared to dietary lipid rich in polyunsaturated fatty acid with the dietary lipid rich in monounsaturated fatty acids was more beneficial to provide energy for juvenile crab.2.The effects of different lipid sources and levels on growth performance,antioxidant and digestive enzyme activity of juvenile Chinese mitten crab,Eriochier sinensis.To evaluate the effects of dietary fatty acid and lipid levels on growth,antioxidant capacity and digestive enzyme activities of the Eriocheir Sinensis.Eight purified diets with four different lipid sources and two lipid levels(6% and 12%)were formulated.Diets including palm oil(rich in palmitic acid,PA),olive oil(rich in oleic acid,OA),safflower oil(rich in linoleic acid,LA)and perilla oil(rich in linolenic acid,LNA),were grouped as 6% PA,6% OA,6% LA,6% LNA,12% PA,12% OA,12% LA and 12% LNA.Each lipid sources was mixed by the ratio of 9:1 for vegetable oil and refined fish oil.To ensure the uppermost fatty acid in each group have same level purified palmitic acid was added with PA group.Each diet was fed to juvenile crabs(0.20±0.01g)in four replicates for 8 weeks.Survival of crabs fed with 12% LNA group were significant lower than 12% OA and 12% LA group.Weight gain of crabs fed 6% PA group were significant higher than 6% OA and 6% LNA group(P<0.05).The content of crude protein and crude lipid for juvenile crab was highest in PA group at the 12% lipid level.The activity of SOD for crab fed 6% LNA and 12%LNA group was lowest at different levels,respectively,while the content of MDA was highest(P<0.05).The activity of amylase for crab fed 12% PA group was significantly higher than 12% LA and 12% LNA group.The results showed that the 6% PA group,which is rich in saturated fatty acids,could better promote the growth of juvenile crabs.while 12% PA group could be beneficial to the accumulation of the crab's crude protein.The LNA group,which is rich in high level of polyunsaturated fatty acid,causeed lipid peroxidative stress for juvenile crab and even result in death.3.The effects of different lipid sources with carnitine on growth performance,antioxidant enzyme activities and composition of hepatopancreas of juvenile Chinese mitten crab,Eriochier sinensis.Eight isonitrogenous and isoenergetic diets were formulated with palm oil(PA),olive oil(OA),safflower oil(LA)and perilla oil(LNA)which added with 0.6% carnitine to evaluate the effect of carnitine on crab fed at high level of lipid(12%).Thirty juvenile crabs(0.20±0.01g)were stocked into each tank(300L)and fed twice daily.After 8-week feeding trial,the survival and weight gain of crabs adding with carnitine in LNA group was increased,but there was no significant difference(P>0.05).,also there was no significant difference for other group.The addition of carnitine significantly increased the content of crude protein and crude lipid for the OA and LNA group(P<0.05).Also,carnitine significantly reduced the conteht of TG in hepatopancreas for the LA group.Carnitine had no significant effect on the activity of SOD enzyme in hepatopancreas,nor did it decrease the content of MDA in each group(P>0.05).The damage of hepatopancreas was still exist.The results showed that the addition of carnitine could increase the crude protein content and the weight gain rate of the young crab,but it could not alleviate the serious damage to the liver and pancreas of young crab.4.The effects of high dietary saturated fatty acid lipid source with silymarin and taurine on growth performance,body composition and antioxidant enzyme activity of juvenile crabs.In this study,isonitrogenous and isoenergetic diets were formulated to explore the appropriate lipid source and feed additive providing abundant energy for juvenile crab(0.18±0.01g).Six semi-purified diets with control oil(fish oil : soybean oil =1:1)and treatment oil(saturated fatty acid 70%~80%,monounsaturated fatty acids about 5%,polyunsaturated fatty acids below 10%,high unsaturated fatty acids about 5%)as lipid source,casein and fish meal as protein source were formulated.Diets were prepared as 13% dietary lipid level 35% dietary protein level with silymarin(0.8%)and taurine(8%)added,respectively,which were S-CO,T-CO,C-CO,S-TO,T-TO and CTO.Each diet was fed to E.sinensis(0.18 ± 0.01 g)in five replicates for 8 weeks.The survival of juvenile crabs was significantly affected by the lipid sources(P<0.05).Silymarin significantly increased the weight gain while decreased the hepatosomatic index of crabs in the TO group,(P<0.05).The content of crude protein and crude lipid were also significantly affected by lipid sources.The content of crude protein for CO group was significantly increased while th content of crude lipid was significantly increased(P<0.05).The body composition was not affected by taurine and silymarin(P>0.05).Taurine significantly reduced the content of glycogen in the hepatopancreas of CO group but had no significant effect on the TO group.Also,the silymarin significantly reduced the content of MDA in hepatopancreas of the CO group(P<0.05).Results showed that high dietary saturated fatty acid oil(TO)at high dietary lipid level won't affect the survival and weight gain of juvenile crabs.The silymarin in the TO lipid source could significantly increase the weight gain and reduce the hepatosomatic index of juvenile crabs.High dietary unsaturated fatty acid lipid source at high dietary lipid level could seriously decrease the weight gain even cause death for crabs,even if the addition silymarin or taurine could not improve the adverse effect.5.The effects of high dietary saturated fatty acid lipid sources and different carbohydrate levels on growth performance,antioxidant and digestive enzyme activity of juvenile crabs.A 8-week feeding trial was conducted to evaluate the effects of high dietary saturated fatty acid oil and different carbohydrate levels on growth and body composition of Eriocheir sinensis(0.18±0.01g).Six semi-purified diets with control oil(fish oil : soybean oil =1:1)and treatment oil(saturated fatty acid 70%~80%,monounsaturated fatty acids about 5%,polyunsaturated fatty acids below 10%,high unsaturated fatty acids about 5%)as lipid source,and corn starch as carbohydrate source were formulated.Diets were prepared as 8% dietary lipid level and three dietary carbohydrate levels,which are 23% CO,23% TO,30% CO,30% TO,37% CO and 37% TO.The weight gain and the specific growth rate were significantly affected by the lipid sources(P<0.05),and the weight gain of the crab for TO group was significantly higher than the CO group(P<0.05).The level of carbohydrate had no significant effect on the weight gain of the CO group,but it significantly affected the weight gain of the TO group.Lipid sources significantly affect the content of crude protein,while the level of carbohydrate significantly affected both the total protein in muscle and whole body(P < 0.05),The content of total protein in 30% CO and 23% TO group was significantly higher than other carbohydrate levels,respectively.Both the lipid sources and the carbohydrate levels could significant affect the digestive enzyme activity of the hepatopancreas and intestine for crabs,and the activity of amylase in both of the lipid sources was the lowest at 37% carbohydrate level(37%).The activity of SOD for crabs was significantly affected by the lipid sources.The activity of SOD for 23% TO group was significantly higher than 23% CO group(P<0.05).The results showed that the high dietary saturated fatty acid lipid source could modify the activity of digestive enzyme,promote the accumulation of protein then increase the growth of crab at the proper level of carbohydrate(23%).While high dietary polyunsaturated fatty acids lipid source or high carbohydrate levels were harmful for crabs.6.The effects of high dietary saturated fatty acid lipid source and protein levels on growth performance,body composition and antioxidant enzyme activity of juvenile crabs.The high level of saturated fatty acids in diet did not affect the growth of the juvenile crabs.Proper additive that could promote fatty acid metabolism can also increase the weight gain of the crabs even spare dietary protein.TO evaluate the interaction effect of high dietary saturated fatty acid and protein levels,eight purified diets were formulated using control oil(fish oil : soybean oil =1:1)and treatment oil(saturated fatty acid 70%~80%,monounsaturated fatty acids about 5%,polyunsaturated fatty acids below 10%,high unsaturated fatty acids about 5%)as lipid source at 12% lipid level.Diet conteined casein as protein sources at protein levels(35% and 40%)and carnitine(0.06%),respectively,which were 35% CO,35% CO+carnitine,40% CO,40% CO+carnitine,35% TO,35% TO+carnitine,40% TO,40% TO+ carnitine.After 8 weeks,the survival for 40% CO,40% CO+carnitine and 35% TO group of crabs was significantly lower than 40% TO group(P < 0.05).The weight gain of crab for 35% TO group was hightest(P < 0.05),and the carnitine did not affect the growth of crabs(P>0.05).The protein level did not affect the content of crude protein and crude lipid of crab,while the content of crude lipid was significantly affected by lipid sources.The content of crude lipid for 40% CO group was significantly higher than 40%TO group(P<0.05).The crude protein for 35%TO group and the crude lipid for 40%CO group were all decreased by the addition of carnitine(P<0.05).The conten of TG in hepatopancreas for 35% CO group was higher than 35% CO+carniting group(P<0.05).The content of MDA for 35% CO group was highest and was not affect by the carnitine.Results showed that the high dietray saturated fatty acids in the diet at the 35% protein level could significantly promote the growth of juvenile crabs.A large accumulation of glycogen and TG in hepatopancreas of juvenile crabs fed diet with high dietary polyunsaturated fatty acids led to lipid peroxidative stress for crabs.The carnitine could reduce the content of TG,but could not alleviate its peroxidative damage. |
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