菜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

Growth,Fatty Acid Composition and Lipid Deposition of Juvenile Turbot( Scophthalmus maximus L.) Fed Diets with Fish Oil Replacement by Rapeseed Oil

本试验旨在研究饲料中菜籽油替代鱼油对大菱鲆(Scophthalmus maximus L.)幼鱼生长、脂肪酸组成以及脂肪沉积的影响。以菜籽油分别替代0、33.3%、66.7%和100.0%的鱼油,配制4种等氮等脂实用饲料。选择初始体重为(5.89±0.02)g的大菱鲆幼鱼420尾,随机分为4组,每组3个重复,每个重复35尾。每种饲料随机投喂1组试验鱼,养殖周期为92 d。结果表明:1)随菜籽油替代水平的升高,大菱鲆幼鱼的终末体重和特定生长率均有下降的趋势,而肝体比则有升高的趋势,其中全菜籽油组的终末体重和特定生长率显著低于全鱼油组(P<0.05),肝体比则显著高于全鱼油组(P<0.05)。菜籽油替代水平并未显著影响大菱鲆幼鱼的存活率、饲料效率、摄食率和表观净蛋白质利用率(P>0.05)。2)菜籽油替代水平并未显著影响大菱鲆幼鱼的体成分、肌肉脂肪含量以及饲料脂肪表观消化率(P>0.05),但显著影响了大菱鲆幼鱼的肝脏脂肪含量(P<0.05)。66.7%菜籽油组和全菜籽油组肝脏脂肪含量显著高于全鱼油组(P<0.05)。3)肝脏和肌肉脂肪酸组成与饲料脂肪酸组成呈正相关关系;相对于全鱼油组,66.7%菜籽油组和全菜籽油组肌肉和肝脏中C18∶2n-6(亚油酸)和α-C18∶3n-3(α-亚麻酸)含量显著升高(P<0.05),而C20∶5n-3(EPA)和C22∶6n-3(DHA)含量显著下降(P<0.05)。综上可知,从营养品质角度考虑,在大菱鲆幼鱼饲料中菜籽油替代鱼油水平应低于66.7%

A 92-d feeding experiment was conducted to investigate the effects of dietary fish oil （ FO） replace-ment by rapeseed oil （ RO） on growth, fatty acid composition and lipid deposition of juvenile turbot （ Scoph-thalmus maximus L.）. Four isonitrogenous and isolipidic practical diets were formulated with RO replacing 0, 33.3%, 66.7% and 100. 0% FO, respectively. A total of 420 juvenile turbot with the initial body weight of （5.89±0.02） g were randomly distributed into 4 groups with 3 replicates per group and 35 fish per replicate, and the fish in each group were randomly fed one of four experimental diets. The results showed as follows：1） with the RO replacement level increasing, the final body weight and specific growth rate of turbot were de-creased, while the hepatosomatic index was increased. The final body weight and specific growth rate in 100.0% RO group were significantly higher than those in 100.0% FO group （P〈0.05）, while the hepatoso-matic index in 100.0% RO group was significantly increased compared with 100.0% FO group （ P〈0.05） . The survival rate,feed conversion rate, feed intake ratio and apparent net protein utilization of turbot were not sig-nificantly affected by RO replacement level （ P〉0.05） . 2） RO replacement level had no significant effects on body composition, muscle lipid content and dietary lipid apparent digestibility of turbot （P〉0.05）, but had significant effect on liver lipid content of turbot （ P〈0.05） . The liver lipid content in 66.7% and 100.0% RO groups was significantly higher than that in 100.0% FO group （P〈0.05）. 3） Fatty acid composition in liver and muscle showed a positive correlation with dietary fatty acid composition. Compared with 100. 0% FO group, the contents of C18∶2n-6 （ linoleic acid） and C18∶3n-3 （α-linolenic acid） in muscle and liver were sig-nificantly increased （ P〈0.05） , while the contents of C20∶5n-3 （ eicosapntemacnioc acid） and C22∶6n-3 （ do-cosahexaenoic acid） in muscle and liver were significantly decreased （ P〈0.05） . These results suggest that on basis of nutritional quality, the level of RO to replace FO in the turbot diet should be lower than 66.7%.