饲料磷脂水平对乌鳢幼鱼生长性能、抗氧化能力及脂肪沉积的影响

Effects of Dietary Phospholipid Level on Growth Performance,Antioxidant Capacity and Fat Deposition of Juvenile Snakehead(Channa argus)

【目的】探究饲料磷脂水平对乌鳢(Channa argus)幼鱼生长性能、抗氧化能力、脂肪酸组成和脂质代谢的影响,为乌鳢健康养殖提供参考。【方法】在基础配合饲料中分别添加质量分数0、2%、4%、6%和8%的磷脂,配制5种等氮等脂饲料(分别记为PL0、PL2、PL4、PL6和PL8),饲喂初始体质量为(3.99±0.01)g的乌鳢幼鱼43 d,测定其生长指标、生理生化指标及肝脏脂代谢相关基因表达量。【结果】1)饲料中磷脂的添加显著影响乌鳢幼鱼的生长性能,PL4组和PL6组幼鱼终末体质量和特定生长率均显著高于PL0组(P<0.05)。日摄食率和饲料系数均呈先降后升的变化趋势,PL4组日摄食率最小,PL6组饲料系数最小,且两者均显著低于PL0组(P<0.05);PL8组幼鱼脏体比显著低于其他各组(P<0.05)。2)随着饲料磷脂水平的升高,乌鳢全鱼和肝脏的粗脂肪含量显著降低,而其水分则呈现出相反的趋势(P<0.05)。3)随着饲料磷脂水平的提高,乌鳢幼鱼肝脏中丙二醛含量呈现降低趋势,PL6组和PL8组显著低于其他组(P<0.05);超氧化物歧化酶活力升高,PL8组显著高于其他组(P<0.05);总抗氧化能力先增高后降低,PL2组显著高于除PL6组以外的其他组(P<0.05);过氧化氢酶活力则不受饲料中磷脂含量变化的影响(P>0.05)。4)在饲料中添加磷脂显著提高幼鱼鱼体和肝脏的n-3多不饱和脂肪酸(PUFA)含量(P<0.05)。5)磷脂的添加对肝脏脂肪代谢相关基因表达有显著影响,PL8组幼鱼的脂肪生成相关基因acc1的表达量显著低于PL0组(P<0.05);PL4和PL6组幼鱼的脂肪分解相关基因mgl表达量显著高于PL0组(P<0.05),PL6组幼鱼的hsl表达量显著高于PL0组(P<0.05);PL6组幼鱼的脂肪酸氧化相关基因pparα、cpt1和aco的表达量显著高于PL0组(P<0.05)。【结论】在饲料中添加磷脂可显著提高乌鳢幼鱼的生长性能,提高其抗氧化能力,并可通过调节脂质代谢显著降低肝脏脂质沉积。乌鳢幼鱼对饲料中磷脂的最适需求量为5.36%。

【Objective】The aim of this paper is to explore the effects of dietary phospholipid level on growth performance,antioxidant capacity,fatty acid composition and lipid metabolism of juvenile snakehead(Channa argus).【Methods】Snakehead fry with an initial body mass of(3.99±0.01)g were fed with five iso-nitrogenous and iso-lipidic diets prepared by adding 0,2%,4%,6%and 8%phospholipids to the basal diet,respectively designated as group PL0(control group),PL2,PL4,PL6 and PL8.At the end of the 43-day's culture experiment,the growth indicators,physiological and biochemical indicators and the expression levels of lipid metabolism-related genes in the liver of the juvenile snakehead were measured.【Results】1)The addition of phospholipids in the diet significantly affected the growth performance of juvenile snakehead.The final body mass and specific growth rate of the juvenile snakehead in group PL4 and group PL6 were significantly higher than those in group PL0(P<0.05).The daily feed intake(FI)and feed conversion ratio(FCR)showed a trend of decreasing first and then increasing.The FI in group PL4 was the lowest,and the FCR in group PL6 was the lowest,both of which were significantly lower than those in group PL0(P<0.05).Meanwhile,the viscerosomatic index(VSI)of the fry in group PL8 was significantly lower than that of the other groups(P<0.05).2)With the increase of dietary phospholipid level,the increase of phospholipid content in the diet significantly reduced the crude fat content of the whole fish and liver,while the moisture showed the opposite trend(P<0.05).3)With the increase of dietary phospholipid level,the malondialdehyde content in the liver decreased more significantly in groups PL6 and PL8 than in the other groups(P<0.05);the superoxide dismutase activity in the liver increased more significantly in group PL8 than in the other groups(P<0.05);the total antioxidant capacity increased first and then decreased,and the capacity in group PL2 was significantly higher than that of the other groups except PL6(P<0.05);the catalase activity was not affected by the change of phospholipid content in the diet(P>0.05).4)The addition of phospholipids in the diet significantly increased the n-3PUFA content of the fish body and liver(P<0.05).5)The addition of phospholipids also had a significant effect on the expression of lipid metabolism-related genes in the liver.The expression level of acc1,a lipid synthesis-related gene,in group PL8 was significantly lower than that in PL0 group(P<0.05);the expression levels of mgl and hsl,lipid degradation-related genes,in groups PL4 and PL6 were significantly higher than those in group PL0(P<0.05),and hsl in group PL6 was significantly higher than that in group PL0(P<0.05);the expression levels of pparα,cpt1 and aco,fatty acid oxidation-related genes,in group PL6 were significantly higher than those in group PL0(P<0.05).【Conclusion】Adding phospholipids to the diet can significantly improve the growth performance of juvenile snakehead,and enhance their antioxidant capacity and reduce lipid deposition by regulating lipid metabolism.The suitable dietary phospholipid requirement for juvenile snakehead was 5.36%.