大黄鱼仔、稚、幼鱼发育阶段的脂肪酸组成及其变化

Fatty acid composition and their changes in larvae and juveniles of Pseudosciaena crocea

研究了大黄鱼早期主要发育阶段（前仔鱼期、后仔鱼期、稚鱼、幼鱼）体内脂肪酸的组成及含量的变化规律，并重点比较了发病稚鱼与正常稚鱼的脂肪酸组成。用GC／MS法共检测到24种脂肪酸，且种类随发育而递增，其中饱和脂肪酸（SFA）12种，单不饱和脂肪酸（MUFA）6种，多不饱和脂肪酸（PUFA）6种。分析结果表明：大黄鱼鱼苗内源性营养阶段以饱和脂肪酸C14：0、C16：0及单不饱和脂肪酸C16：1、C18：1作为能量代谢的主要来源；必需脂肪酸C20：4（n-6）（AA）在鱼苗开口前就已存在，而DHA和EPA摄食后才被检测到，其含量受饵料种类的影响，DHA含量变化范围为7．26％～25．36％，EPA为3．41％～8．40％。与同期正常鱼苗相比，病鱼苗的主要脂肪酸DHA、EPA含量显著降低，DHA不足前者的1／3，而AA、C18：1、C18：2、C18：3含量和EPA／DHA的比值显著增加，分别是前者的1．5—3倍。导致稚鱼阶段“胀鳔病”发生的内在原因可能是DHA和EPA的缺乏以及AA偏高。研究结果为预防“胀鳔”鱼苗的发生提供了理论依据。

The fatty acid composition and their changes at main developmental stages （ prophase-larvae, anaphase-larvae, juvenile and young） of the Pseudosciaena crocea were analyzed by means of GC/MS, and the comparison of fatty acids composition of the diseased juvenile with the normal juvenile was made. The fatty acids were detected, including 12 SFAs,6 MUFAs and 6 PUFAs. C14：0,C16： 0 （SFA） and C16：1,C18：1 （MUFA） were main source of energy metabolism during internal nutrition. The essential fatty acids C20：4（ n- 6）（AA） have existed in the larvae before its first feeding, while the DHA and EPA were only detected after feeding, and were affected by the bait kinds. The ranges of DHA and EPA content variety were 7.26% - 25.36% and 3.41% - 8.40% respectively. Compared with FA composition of the normal juvenile of the same period, the content of DHA and EPA in the juvenile with ＂swim bladder bnlge＂disease decreased clearly,with the DHA content being only 1/3 of the normal one, while the contents of AA,C18：1,C18：2,C18：3 and EPA/DHA specific value increased markedly,being 1.5- 3 times of those in normal juvenile. The inside reason that＂swim bladder bulge＂diseasc took place may be lack of DHA and EPA and higher AA.The research result can offer a theoretical foundation to prevent the ＂swim bladder bulge＂disease.