以初始体质量为(13.56?0.05) g的大黄鱼为对象,研究饲料中菜籽油替代鱼油对大黄鱼生长、肌肉脂肪酸组成和体色的影响。以鱼油组为对照组,用菜籽油分别替代25%、50%、75%、100%的鱼油,配制5种等氮等脂的实验饲料,在海水浮式网箱中进行为期8周的摄食生长实验。结果显示,饲料中不同水平菜籽油替代鱼油对大黄鱼的存活率(SR)和特定生长率(SGR)均无显著性影响;但饲料系数(FCR)随着替代水平的增加呈上升趋势,在100%替代组显著高于对照组。各处理组之间全鱼粗蛋白质、粗脂肪、灰分和水分含量均无显著性差异。肌肉中脂肪酸和饲料中脂肪酸线性关系分析表明,随着菜籽油替代鱼油水平的升高,大黄鱼肌肉中C18∶0、C18∶1、C18∶2n-6和C18∶3n-3含量不断增加,而C20∶4n-6和C22∶5n-3含量不断降低。肌肉中的饱和脂肪酸(SFA)含量随着替代水平的升高而升高,与饲料中SFA含量的变化趋势相反。菜籽油替代鱼油对大黄鱼腹部皮肤亮度值(L^*)无显著性影响,但显著影响了背部皮肤L^*值,100%替代组L^*值显著高于对照组。对照组腹部皮肤红色值(a^*)显著高于替代组;与腹部皮肤红色值相反,对照组背部皮肤红色值低于各替代组。菜籽油替代鱼油对大黄鱼背部和腹部皮肤黄色值(b^*)均无显著性影响。研究表明,在本实验条件下,菜籽油替代鱼油对大黄鱼生长和体组成无显著影响,却显著影响了大黄鱼的肌肉脂肪酸组成和体色。

An 8-week feeding trial was conducted to investigate the effects of dietary fish oil replaced with rapeseed oil on rowth,muscle fatty acid compositions and skin color of large yellow croaker(initial weight 13.56?0.05 g).Five isoproteic and isolipidic experimental diets were formulated with %,25%,50%,75% and 100% replacement of fish oil by rapeseed oil.Results showed that these replacements did not significantly influence the survival rate(SR)and specific growth rate(SGR)(P>0.05).However,the feed conversion ratio(FCR)was ncreased with the increasing of replacement evels.Furthermore,FCR in the group of 100% rapeseed oil was significantly higher than that of 100% dietary fish oil( P<0.05).No significant difference was observed in the whole body compositions(P>0.05).The concentrations of C18∶0,C18∶1,C18∶2n-6,C18∶3n-3 and the saturated fatty acid(SFA),except C20∶4n-6 and C22∶5n-3 in muscle,were elevated with the increasing of dietary rapeseed oil levels.There were no significant differences in yellowness(b^*)of dorsal and ventral skin among the five treatments(P>0.05).Lightness(L^*)of the dorsal skin in the treatment with 100% dietary rapeseed oil was significantly higher than that with 100% dietary fish oil(P<0.05).However,L^*of the ventral skin was not significantly different among the all eatments (P>0.05).Higher redness( ^*)of ventral skin and lower a^* of dorsal skin were found in fish fed with 0% rapeseed oil.This study suggested that there were no ignificant effects of replacement of dietary fish oil by rapeseed oil on growth and body composition.However,the fatty acid omposition of muscle and the skin color were significantly nfluenced.

公益性行业(农业)科研专项(200903029)