再投喂鱼油对瓦氏黄颡鱼肌肉脂肪酸组成的影响

为研究植物油替代鱼油对瓦氏黄颡鱼（Pelteobagrus vachelli）生长及肌肉脂肪组成的影响及重投喂鱼油对瓦氏黄颡鱼肌肉脂肪酸组成的影响，实验以大豆油分别替代饲料中的0（FO）、50（S1）、75（S2）和100%（SO）的鱼油配制等氮、等能的颗粒饲料，每组设置3个平行，养殖80d后，再投喂鱼油30d。结果表明，饲料中添加豆油不会显著影响瓦氏黄颡鱼的增重率、肝体指数和体成分（P>0.05）。随着饲料中大豆油含量的增加，S2和SO组肌肉中C18:1n-9、C18:2n-6和单不饱和脂肪酸比例显著增加（P < 0.05），而C20:5n-3，C22:5n-3及n-3/n-6比例显著下降（P < 0.05）。再投喂鱼油30d后，SO组肌肉中C18:3n-6、C20:4n-6、Σ n-9、Σ n-6和S2组中C18:1n-9、Σ n-6比例显著下降（P < 0.05），而S2和SO组肌肉中Σn-3多不饱和脂肪酸、C20:5n-3和C22:5n-3比例显著增加（P < 0.05）。在生产中，可采用先植物油饲料、后鱼油饲料的养殖方式提高瓦氏黄颡鱼肌肉品质（增加有益人类健康的多不饱和脂肪酸）。

RESTORATION OF FLESH FATTY ACID COMPOSITION IN DARKBARBEL CATFISH (PELTEOBAGRUSVACHELLI) USING A FINISHING FISH OIL DIET

This study aimed to evaluate the effects of 50%—100%soybean oil on growth performance and flesh fatty acid composition of darkbarbel catfish (Pelteobagrus vachelli), so as to assess the effects of re-feeding fish oil (FO) on flesh fatty acid composition. Four isonitrogenous, isolipidic diets, i.e., FO, soybean oil (SO), 50%FO+50%SO (S1), and 25%FO+75%SO (S2), were fed to triplicate groups of 40 juvenile P. vachelli (1.10±0.12) g] for 80d. At the end of the 80d period, all fish were fed with FO for 30d. The results showed that growth rates, hepatosomatic index (HSI), and proximate composition in darkbarbel catfish were not affected by SO. With increasing SO levels, the percentages of oleic acid, arachidonic acid, and monoun-saturated fatty acids significantly increased (P<0.05). However, docosahexaenoic acid (DHA), eicosapentae-noic acid (EPA), highly unsaturated fatty acid (HUFA) levels and n-3/n-6 ratios significantly reduced with die-tary SO (P<0.05). After 30d on FO, flesh levels of DHA, EPA, andΣn-3 HUFA significantly increased in groups S2 and SO (P<0.05), but not to the same extent as those in the FO-containing groups except S1. The results revealed that it was possible to substitute almost 100%of FO with SO in the diets of darkbarbel cat-fish without affecting growth performance. A re-feeding period of 30d with 100%FO significantly increased flesh levels ofΣn-3 HUFA, 20:5n-3, and 22:6n-3 in fish which were fed diets containing SO in the first stage.