黄颡鱼早期发育阶段受精卵和鱼体脂肪酸组成变化

Changes in fatty acid composition during development in Pelteobagrus fulvidraco fertilized eggs and larvae

研究了黄颡鱼受精卵孵化期间和仔鱼发育阶段脂肪含量和脂肪酸的组成变化规律。采用常规化学分析方法和气相色谱法对黄颡鱼从鱼卵受精开始至仔鱼孵化后未投饵的7d内的脂肪含量和脂肪酸组成进行测定。结果表明,受精卵在整个孵化期间脂肪含量有下降趋势。受精卵中不饱和脂肪酸含量大于饱和脂肪酸含量。受精卵在整个孵化期间各种脂肪酸含量无明显变化。仔鱼孵化后,鱼体总脂肪含量急剧下降,总脂含量从0日龄的4.57%降低到7日龄的0.75%。仔鱼在饥饿期间鱼体脂肪酸组成发生明显变化,单不饱和脂肪酸含量下降最为明显,尤其是C18∶1。仔鱼在饥饿期间,脂肪酸按n-9>n-6>n-3顺序被先后利用,黄颡鱼仔鱼发育阶段主要以单不饱和脂肪酸作为能量代谢基质,而C20∶4n6(AA)和C22∶6n3(DHA)优先于C20∶5n3(EPA)被保存下来。

To establish the changes which during embryogenesis and early larval development, fertilized eggs and larvae of Pelteobagrus fulvidraco were examined for lipid content and fatty acid compositions. The lipid content and fatty acid composition in the fertilized eggs and larvae which did not feed for 7 days after hatching were analyzed by means of common chemical assay and gas chromatography （GC）. The results showed that the lipid content of fertilized eggs tended to increase during hatching period. Fertilized eggs contained more polyunsaturated fatty acids （PUFA） and monounsaturated fatty acids （MUFA） than saturated fatty acids （SFA）. There was no significant change in the proximate fatty acid composition of eggs during hatching. The lipid content of larvae decreased sharply after hatching. Total lipid decreased from 4.57 % on day 0 to 0.75 % on day 7. The fatty acid composition in starved larvae changed significantly as starvation progressed. In starved larvae the MUFA content decreased significantly and the greatest decrease occurred in the C18 ： 1 content. In this regard the degree of decreases was, n- 9〉n- 6〉n- 3, suggesting that MUFA were a major energy source for starving Pelteobagrus fulvidraco larvae, DHA and AA were conserved in preference to EPA.