亚麻籽油替代鱼油对大菱鲆幼鱼生长、脂肪酸组成及脂肪沉积的影响

为研究亚麻籽油替代不同鱼油水平对大菱鲆幼鱼初始体质量为(5.89±0.02)g]生长、脂肪酸组成以及肝脏和肌肉脂肪沉积的影响,以亚麻籽油分别替代0、33.3%、66.7%和100%鱼油,配制4种等氮等脂饲料。每组饲料随机投喂3组实验鱼,饱食投喂,养殖周期为92 d。结果发现,饲料亚麻籽油水平并未显著影响大菱鲆幼鱼存活率(SR)和特定生长率(SGR),但显著影响其摄食率(FI)、饲料效率(FE)和表观净蛋白利用率(ANPU)。随饲料亚麻籽油水平升高,FI显著升高,而FE和ANPU显著下降,且其均在100%亚麻籽油组分别达到最大值或最小值。饲料亚麻籽油水平并未显著影响大菱鲆饲料脂肪表观消化率、肝体比和肌肉脂肪含量。当饲料中亚麻籽油替代100%鱼油,鱼体肝脏脂肪含量显著高于全鱼油组。肝脏和肌肉脂肪酸组成与饲料脂肪酸组成相似。相对于全鱼油组,亚麻籽油替代组肌肉和肝脏中亚油酸和亚麻酸显著升高,而EPA和DHA含量显著下降。研究表明,大菱鲆饲料中亚麻籽油替代水平应低于66.7%,且大菱鲆饲料中n-3长链多不饱和脂肪酸含量需大于0.8%。

Growth performance,fatty acids composition and lipid deposition in juvenile turbot(Scophthalmus maximus)fed diets with various fish oil substitution levels by linseed oil

(Objective) A 92-d feeding experiment was conducted to investigate the effects of dietary graded level of linseed oil (LO) on growth performance, fatty acids composition and lipid deposition of liver and muscle in juvenile turbot (Scophthalmus maximus L.) (mean initial body weight, 5.89 ± 0.02g). (Method) Four isonitrogenous and isoenergetic practical diets were formulated with LO replacing 0%, 33.3%, 66.7% and 100% fish oil (FO), respectively. Each diet was randomly fed to triplicate groups in indoor seawater recirculation system to apparent satiation. (Result) The results showed that survival rate (SR) and specific growth rate (SGR) of juvenile turbot were independent of dietary LO level (P>0.05). With increasing dietary LO level, feed intake (FI) of turbot significantly increased, while feed efficiency (FE) and apparent net protein (ANPU) significantly decreased (P<0.05), and they were up to the maximum and minimum in 100% LO group, respectively. Apparent digestibility coefficient of dietary lipid, hepatosomatic index and lipid content of muscle were also independent of dietary LO level (P>0.05). Lipid content of liver in turbot significantly increased with increasing dietary LO levels (P<0.05), which in 100% LO group was significantly higher than that in FO group (P<0.05). Fatty acid composition of total lipid in liver and muscle was closely correlated with those in diets. With increasing dietary LO levels, the content of linoleic acid and linolenic acid significantly increased, while the content of EPA and DHA significantly decreased (P<0.05). (Conclusion) These results suggested that on basis of nutritional quality, the LO replacement level in turbot diet should be lower than 66.7%.