| The experiment was conducted to investigate the regulation mechanism of dietary vitamin E(VE)on dietary lipid induced oxidative stress of Macrobrachium rosenbergii.Firstly,through the experiment of feeding fish oil and oxidized fish oil,we explored the influences of oxidized lipid diet on oxidative stress in M.rosenbergii.Then,juvenile prawn were fed with diets containing different vitamin E levels,according to growth performance,serum biochemical index and muscle quality index,the appropriate vitamin E demand for M.rosenbergii was determined.Finally,diets containing different VE and fat levels was set to investigate the specific regulatory approach of vitamin E through NF-κB pathway on high-lipid induced oxidative stress.The main research contents and results are as follows:1.Effects of fish oil and oxidized fish oil on digestive enzyme activity and antioxidant stress system of M.rosenbergii:We used basic diet(Con),basic diet with 4%fresh fish oil(4F)and 4%oxidized fish oil(4OF)feed the 7-day-old M.rosenbergii larvae for 14 days,respectively.The results showed that:(1)after feeding,protease activity of T2 and T3 larvae in group 4OF was significantly higher than that of T1 larvae,lipase activity of T3 larvae in group 4OF was significantly higher than that of T1 larvae,amylase activity of T3 larvae in group Con,4F and 4OF was significantly higher than that of T1 and T2 larvae(P<0.05).Protease activity of T2 larvae in group 4OF was significantly higher than that in group Con and 4F,amylase activity of T2 larvae in group Con was significantly higher than that in group 4F and 4OF(P<0.05).(2)after feeding,T-SOD and GSH-Px activity of T3 larvae in group 4OF was significantly higher than that of T1 and T2 larvae,MDA and LZM content of T3 larvae in group Con was significantly higher than that of T1 and T2 larvae,MDA content of T2 and T3 larvae in group 4OF was significantly higher than that of T1 larvae,LZM content of T3 larvae in group 4OF was significantly higher than that of T2 larvae(P<0.05).MDA content of T2 and T3 larvae in group 4OF was significantly higher than that in group Con and 4F,LZM content of T3 larvae in group Con was significantly higher than that in group 4F and 40F(P<0.05).(3)after feeding,compared with that of T1 and T3 larvae in group Con,gene IKKβ mRNA expression level of T2 larvae significantly up-regulated;compared with that of T2 larvae,gene Toll mRNA expression level of T3 larvae significantly down-regulated;compared with that of T1 and T2 larvae,gene Relish mRNA expression level of T3 larvae significantly up-regulated(P<0.05).Compared with that of T1 larvae in group 4F,gene Relish mRNA expression level of T2 larvae significantly up-regulated;compared with that of T1 and T3 larvae,gene IκBαmRNA expression level of T2 larvae significantly down-regulated;compared with that of T1 and T2 larvae,gene HSP70 mRNA expression level of T3 larvae significantly down-regulated(P<0.05).Compared with that of T1 larvae in group 4OF,gene Toll mRNA expression level of T3 larvae significantly down-regulated;compared with that of T1 larvae,gene HSP70 mRNA expression level of T3 larvae significantly up-regulated(P<0.05).Gene Toll mRNA expression level of T2 larvae in group 4F and 4OF was significantly lower than that in group Con,gene Relish mRNA expression level of T2 larvae in group 4F was significantly higher than that in group Con(P<0.05).Gene IκBα mRNA expression level of T2 larvae in group 4F was significantly lower than that in group Con,gene IKKβ mRNA expression level of T2 larvae in group 4F and 4OF was significantly lower than that in group Con(P<0.05).Gene Toll mRNA expression level of T3 larvae in group 4F was significantly higher than that in group Con,gene HSP70 mRNA expression level of T3 larvae in group 4F and 4OF was significantly higher than that in group Con(P<0.05).2.Effects of dietary vitamin E on growth performance,immunity,oxidation resistance and muscle quality of M.rosenbergii:A total of 250 healthy prawns with the same initial body weight(0.243±0.003 g)were selected and randomly divided into five groups.Five isonitrogenous and isoenergetic purified diets were formulated to contain 0.6,103.4,207.1,412.9 and 631.7 mg vitamin E per kg of diet,as group VE1,VE2,VE3,VE4 and VE5,respectively.After 62-day feeding trail,(1)the specific growth ratio was significantly increased under dietary vitamin E stimulation compared with control group(P<0.05);group VE5 significantly enhanced the condition factor(P<0.05).(2)Compared with control group,plasmatic alanine aminotransferase was significantly decreased in group VE2,VE3 and VE5(P<0.05);aspartate aminotransferase activity was significantly decreased in group VE3(P<0.05);cholesterol content was significantly decreased in group VE3 and VE5(P<0.05);while triacylglycerol content was significantly increased in group VE5(P<0.05).(3)MDA content in group VE4 and VE5 was significantly lower than that in group VE1,SOD activity in group VE3 was significantly higher than that in group VE1(P<0.05).(4)The flesh content in group VE2 and VE3 was significantly increased compared with control group(P<0.05),while water retention as drip loss,cooking loss and malondialdehyde content were significantly decreased in group VE2,VE3 and VE5(P<0.05),respectively;vitamin E content in muscle was significantly decreased in group VE3,VE4 and VE5(P<0.05).(5)Springiness of the muscle was significantly increased in group VE2 compared with control group(P<0.05);hardness,cohesiveness,chewiness and gumminess were significantly decreased in group VE3 and VE4(P<0.05);while springiness and tenderness were significantly increased in group VE4(P<0.05).According to the broken-line regression analysis of specific growth ratio and cooking loss respectively,we recommend the optimal dietary vitamin E requirement of size for M.rosenbergii can be 169.38 mg/kg of diet and 218.66 mg/kg of diet.Based on our results,we conclude that ingestion with 169.38-218.66 mg/kg vitamin E promotes growth performance,enhances immune activity and muscle quality of M.rosenbergii.3.Effects of vitamin E on high lipid-induced oxidative stress in M.rosenbergii:Rosenbergii juvenile were fed with four diets containing 8%fat+200 mg/kg VE,8%fat+600 mg/kg VE,12%fat+200 mg/kg VE and 12%fat+600 mg/kg VE for 62 days.The results showed that:(1)high fat significantly reduced SR,FR and SGR of M.rosenbergii(P<0.05).Under the condition of high fat,600 mg/kg VE significant increased its growth performance.(2)ALT and AST activity were significantly increased in the high-fat group,TC content was significantly reduced.Under the condition of high fat,600 mg/kg VE significantly reduced ALT and AST activity,and significantly reduced TC content(P<0.05).(3)high fat significantly decreased SOD and GSH-Px activity,increased ASOR activity and MDA content.Under the condition of high fat,600 mg/kg VE significantly increased GSH-Px activity,decreased MDA content(P<0.05).(4)high fat significantly decreased interleukin-1(IL-1)content in serum,increased interferon-y(INF-γ)content;600 mg/kg VE significantly decreased serum tumor necrosis factor-β(TNF-α),IL-1 and IL-6 contents(P<0.05).(5)high fat significantly decreased serum iNOS activity and NO content,had no significant influence on them(P>0.05).Relish、IκBα、IKKβ、Toll and Dorsal mRNA relative expressions in high-fat group were significantly down-regulated,IMD mRNA relative expression was significantly up-regulated,and 600 mg/kg VE significantly decreased IMD、Relish and IκBα mRNA relative expressions(P<0.05).Generally,high fat cause growth inhibition,oxidation resistance and nonspecific immunity decline.Under the condition of high fat,the supplement of high dose VE(600 mg/kg)can improve its growth to a certain extent,and has a certain repair effect on the immune dysfunction induced by high fat,and relieve the oxidative stress injury induced by high fat through the NF-κB signaling pathway. |
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