日本鬼鲉胚胎及卵黄囊仔鱼发育过程中脂肪及脂肪酸特性变化

The changes in lipid and fatty acid profiles of devil stinger Inimicus japonicas during the development of embryo and yolk-sac larvae

以野生日本鬼鲉人工催产获得的受精卵为实验材料,定量检测了日本鬼鲉胚胎及卵黄囊仔鱼发育过程中脂肪组成及脂肪酸含量。结果表明:日本鬼鲉胚胎及卵黄囊仔鱼的总脂肪含量为13.85%～11.66%,极性脂肪占总脂肪含量为75.39%～72.20%。总脂肪及极性脂肪含量在胚胎发育阶段无显著变化,在卵黄囊仔鱼阶段随发育而显著下降。中性脂肪含量在胚胎发育阶段有显著变化,在卵黄囊仔鱼阶段其含量相对稳定。野生日本鬼鲉胚胎及卵黄囊仔鱼总脂肪的主要脂肪酸为DHA(22∶6n-3),16∶0,ARA(20∶4n-6),EPA(20∶5n-3),18∶0和18∶1n-9。总脂肪及极性脂肪的DHA,ARA,EPA含量(mg/gDW)均随胚胎和卵黄囊仔鱼的发育而显著下降,且DHA和ARA含量均在胚胎囊胚期至尾芽期大幅降低。中性脂EPA和DHA含量随发育呈先升后降,其峰值分别出现在初孵仔鱼和2日龄(2DPH)卵黄囊仔鱼。中性脂ARA含量随发育逐步升高,峰值出现在3日龄(3DPH)卵黄囊仔鱼。在胚胎发育前期,总脂肪DHA和ARA相对EPA被选择性消耗,饱和脂肪酸(SFAs)和多不饱和脂肪酸(PUFAs)相对单不饱和脂肪酸(MUFAs)被机体选择性消耗,N-6PUFA相对N-3PUFA被选择性消耗;在胚胎发育后期及卵黄囊仔鱼阶段,总脂肪EPA相对DHA和ARA被选择性消耗。在胚胎和卵黄囊仔鱼发育过程中,SFAs中16∶0相对18∶0被选择性消耗。胚胎发育后期阶段和卵黄囊仔鱼阶段,总脂肪MUFAs中16∶1相对18∶1被选择性消耗。实验表明日本鬼鲉胚胎及卵黄囊仔鱼发育阶段极性脂肪中DHA、ARA和EPA可以向中性脂肪中转移,胚胎和卵黄囊仔鱼对不同类别脂肪中的重要脂肪酸的消耗具有选择性,且其选择性与发育阶段相关。

wild-caught broodstocks of devil stinger Inimicus japonicas were induced with LHRH-A3 to spawn and the fertilized eggs were incubated artificially in seawater with salinity 29 at 20 ℃.The lipid compositions and fatty acid profiles of the embryos（blastula stage to tail-bud stage）and yolk-sac larvae[newly hatched,1 day post hatching（DPH）,2 DPH,3 DPH（unfed）]were investigated.The results indicated that the total lipid content of devil stinger decreased from 13.85% of the blastula stage embryos to 11.66% of 3 DPH larvae.Polar lipid accounted for 72.20%-75.39% of total lipid during the early development.There was no significant difference in total lipid and polar lipid contents during embryogenesis.The total lipid and polar lipid contents declined significantly during the development of yolk-sac larvae.The neutral lipid content first increased,then decreased significantly during embryogenesis and kept stable during the development of yolk-sac larvae.DHA（22∶ 6n-3）,16∶ 0,ARA（20∶ 4n-6）,EPA（20∶ 5n-3）,18∶ 0 and 18∶ 1n-9 were the dominant fatty acids in total lipid of embryos as well as of yolk-sac larvae.The contents（mg/gDW）of DHA,ARA and EPA in total lipid as well as in polar lipid declined significantly during the early development of the devil stinger.There was sharp declining in contents of DHA and ARA in total lipid as well as in polar lipid when the embryo developed from blastula stage to tail-bud stage.The EPA and DHA contents in neutral lipid first increased,then decreased during the early development and the peak appeared at newly-hatched larvae stage and 2 DPH larvae respectively.The ARA content in neutral lipid increased step by step during the early development.DHA and ARA to EPA,saturated fatty acids（SFAs）and poly-unsaturated fatty acids（PUFAs）to mono-unsaturated fatty acids（MUFAs）as well as N-6 PUFA to N-3PUFA were preferentially utilized in total lipid during the early embryonic development.While EPA to DHA and EPA to ARA in total lipid were preferentially utilized during the later embryogenesis and development of yolk-sac larvae.Among the SFAs,16∶ 0 to 18∶ 0 was preferentially utilized during the whole early development.Among the MUFAs,16∶ 1 to 18∶ 1 was preferentially utilized during the later embryogenesis and development of yolk-sac larvae.It was therefore suggested that DHA,EPA and ARA in polar lipid could be transferred into neutral lipid during the early development of devil stinger.And the preferential utilization of some fatty acids depended on the lipid class and the development stage of the embryo and yolk-sac larvae.