饲料中不同脂肪酸对草鱼组织脂质含量和脂肪酸构成的影响

实验选用初始作重约1．4g的草鱼，在60天的饲养期中分别投喂1种不含脂肪的饲料和8种含3％不同脂质的饲料，观察了饲料中添加油酸（18：1n-9）、亚油酸（18：2n－6）、亚麻酸（18：3n－3）和n－3系列高度不饱和脂肪酸（n－3HUFA；20：5n－3＋22：6n－3）对草鱼肝胰脏、肌肉、头部和去肝胰脏内脏脂质含量和脂肪酸构成的影响。实验结果表明，与摄食单纯含油酸饲料的草鱼相比，含1％18：2n－6和1％18：3n－3或1％18：2n－6和0．5％n－3HUFA饲料组草鱼的肝胰脏脂质含量显著降低，但内脏脂质含量升高。向饲料中添加18：2n－6、18：3n－3和n－3HUFA能明显影响草鱼肝胰脏、肌肉和头部脂质多不饱和脂肪酸的相对含量；组织中n－6系列和n－3系列高度不饱和脂肪酸含量分别与饲料中添加18：2n－6和18：3n－3有相关关系，表明草鱼具有生物转化18：2n－6和18：3n－3为高度不饱和脂肪酸的能力。

EFFECT OF DIFFERENT DIETARY FATTY ACIDS ON TISSUE LIPID CONTENT AND FATTY ACID COMPOSITION OF GRASS CARP

Grass carp, Cienopharyngodon idellus (C. et V. ), weighing about 1. 4g, were fed re-spectively on a fat - free diet and on eight diets containing 3 % different lipids. After a 60 -day feeding period, the lipid content and fatty acid composition of hepatopancreas, muscle,head and vicera without hepatopancreas were examined. In the grass carp fed diets supple-mented with 1% 18: 2n - 6 + 1 % 18; 3n - 3 or 1 % 18: 2n - 6 + 0. 5% n - 3 polyunsaturatedfatty acids(n - 3HUFA, 20: 2n - 3 + 22: 6n - 3), the lipid content of hepatopancreas waslower than in the fish fed the diet containing 18: 1n - 9 alone, but the lipid level of visceracontaining no hepatopancreas was higher. The addition of 18: 2n - 6 or18: 3n - 3 or n -3HUFA to the diets affected greatly the fatty acid composition of the organs examined,showing a correlative relationship between the tissue n - 6HUFA(20: 4n - 6, 22: 5n - 6) orn - 3HUFA(20: 5n - 3, 22: 611 - 3) content and the dietary 18: 2n - 6 or 18: 3n - 3. It wassuggested, from this result, that these two fatty acids could be converted to n - 6HUFA orn - 3HUFA in grass carp, respectively.