饲料脂肪水平对梭鱼脂肪沉积、脂肪代谢酶及抗氧化酶活性的影响

Effects of dietary lipid levels on fat deposition,lipid metabolize enzyme and antioxidantic activities of Chelon haematocheilus

为了探讨饲料脂肪水平对梭鱼(Chelon haematocheilus)脂肪沉积、脂肪代谢酶及抗氧化酶活性的影响,选取360尾平均体质量为(5.4±0.2)g的梭鱼鱼种,随机分为6组,每组3个重复,每个重复20尾鱼,分别投喂脂肪含量为2.71%、5.79%、8.23%、11.85%、14.39%、16.91%的6组等氮饲料,饲养60 d,测定相应生物学指标及酶活。研究结果表明,随着脂肪水平的升高,肝体指数、脏体指数显著升高(P<0.05),肥满度8.23%组最大,其显著高于2.71%组(P<0.05);梭鱼全鱼、肝脂肪含量显著升高(P<0.05),14.39%组全鱼脂肪含量最高,16.91%组肝脂肪含量最高。饲料脂肪水平对肝脂肪代谢酶有显著影响(P<0.05),其中脂蛋白酯酶(LPL)、肝酯酶(HL)、总酯酶(GE)活性随着饲料脂肪水平的升高显著增高(P<0.05),16.91%组显著高于2.71%、5.79%、8.23%组(P<0.05);苹果酸脱氢酶活性呈显著下降趋势(P<0.05);血液中甘油三酯(TG)、总胆固醇(CHO)、游离脂肪酸(EFA)有升高趋势,但各组差异不显著(P>0.05);脂肪水平16.91%组高密度脂蛋白胆固醇(HDL)含量最高,显著高于脂肪水平2.71%的组(P<0.05);肝胰脏超氧化物歧化酶(SOD)活性随着饲料脂肪水平的升高呈先上升后下降的趋势,8.23%组活性最高,丙二醛(MDA)含量16.91%组显著高于其他5组(P<0.05)。结果显示,肝是梭鱼脂肪沉积的主要场所,肝脂肪沉积比肌肉更敏感,高脂肪饲料还使脂肪分解酶的活性增强,血脂含量增加;适宜的饲料脂肪水平可提高梭鱼的抗氧化能力,脂肪水平过高则会导致抗氧化能力下降。

We evaluated the effects of dietary lipid levels on fat deposition,lipid metabolism enzymes,and antioxidant activity in Chelon haematocheilus.The fish（mean weight 5.40±0.16 g） were assigned to one of six treatment groups（triplicate,n=20 fish/replicate） and fed one of six isonitrogenous diets containing 2.71%,5.79%, 8.23%,11.85%,14.39%,or 16.91% lipid for 60 d.Increases in the dietary lipid level were associated with a significant increase in the hepatosomatic and viscerosomatic indexes（P0.05）.Condition factor was highest in the group fed 8.23% lipid,and was significantly higher than the group fed 2.71% lipid（P0.05）.There was a significant increase in fat deposition in the whole body and liver as the level of dietary lipid increased.The whole body lipid content was highest in the group fed 14.39% lipid whereas liver lipid was highest in the group fed 16.91% lipid.Dietary lipid had a significant effect on lipid metabolic enzymes（P0.05）.Lipoprotein lipase,HL,and the general esterase all increased with an increase in dietary lipid levels.The levels were significantly higher in the group fed 16.91% lipid than in the groups fed ≤8.23% lipid（P0.05）.Conversely,the levels of malic dehydrogenase tended to decrease with increasing dietary lipid levels.Levels were significantly higher in the group fed 2.71% lipid than in all other groups（P0.05）.Blood fat also increased as the level of dietary lipid increased,but there was no change in TG,CHO,and EFA.High density lipoproteins were significantly higher in the group fed 16.91% lipid than in those fed 2.71% lipid（P0.05）.Liver superoxide dismutase（SOD） activity increased then decreased as the level of dietary lipid increased.The point of inflection was around 8.23% lipid.Malondialdehyde（MDA） content was significantly higher in the fish fed 16.91% lipid than that of other five groups（P0.05）.In summary,our results suggest that higher dietary lipid increases the hepatosomatic and viscerosomatic indexes as well as fat deposition.The liver is the primary place for fat deposition,so was more sensitive than muscle.The higher levels of dietary lipid also increased lipid enzymatic activity and blood fat content.Optimal dietary lipid levels enhanced antioxidant activity in C.haematocheilus,although excess lipid levels were associated with a decrease in antioxidant activity.