| 摘要: |
| 本文以产沉(粘)性卵的鲱(Clupea harengus L.)和浮性卵的鲽(Pleuronectes platessa L.)为代表,对这两类海洋鱼类在卵和卵黄囊期仔鱼发育阶段水分、钠、钾、脂肪和蛋白质含量变化作了比较研究。实验于1987年春在苏格兰完成。结果发现:1) 鲱的含水量在三个阶段有明显增长,受精时从75％ - 85％,卵发育期从85％ - 87％,孵化后从85％ - 90％; 通过这一成功变化,最终使仔鱼获得浮性,上升并进入浮游生物水层摄食;鲽卵含水量在这三个阶段均保持在90％ - 92％,并一直保持相应的浮性,至摄食期。2) 两种初孵仔鱼含水量的差别,主要由卵黄囊含水量不同引起,而身体其它部分含水量没有显著种的差别。3) 鲱在钠、钾含量上的增长和波动,大致同这三个阶段湿重和含水量的增长和波动一致。4) 脂肪和蛋白质对卵和仔鱼的浮性几乎不起作用;两种鱼在卵和卵黄囊期发育阶段,脂肪和蛋白质含量均呈线性下降。 |
| 关键词: 鲱 鲽 卵 卵黄囊期仔鱼 发育 生化变化 |
| DOI： |
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| 基金项目:苏格兰海洋生物协会（SMRA）资助 |
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| BIOCHEMICAL CHANGES DURING DEVELOPMENT OF EGGS AND YOLK-SAC LARVAE OF HERRING AND PLAICE |
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Yin Mingcheng(M. C. Yin)1, J.C.A.Craik2
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1.Shanghai Fisheries University 200090;2.SMBA Dunstaffnage Marine Research Laboratory, U. K.
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| Abstract: |
| Biochemical changes (water, sodium, potassium, lipid and protein) in developing eggs and yolk-sac larvae were compared in the herring Clupea harengus L., a species with demersal eggs, and the plaice Pleuronectes platessa L., a species with pelagic eggs. Spawning herring and plaice were caught in the Clyde, Scotland in March 1987. Wet and dry weight were determined on duplicate samples of 60 eggs and 20-30 larvae. Weight loss of larvae between sampling and weighing on a microbalance was corrected by successively weighing at 4 intervals of min and extrapolating linearly backward in time. Dried samples were used for determination of sodium and potassium by flame emission spectrophotometry. Lipid was extracted on duplicate samples of 60 eggs and 90 larvae by the method of Bligh and Dyer (1959). The solids insoluble in the extraction were dried and weighed to give the protein.
The principal difference between the two species was that in the herring, but not in the plaice, there was considerable increase in water content at three distinct stages: from 75% to 85% at fertilization (tab. 2), from 85% to 87% during egg development (Fig. l),. and from 85% to 90% after hatching (Fig. 4). These changes finally confer buoyancy on the herring larvae, allowing it to enter the planktonic zone for feeding. However, the water content of the plaice remained at 90%-92% during these stages. Secondly, newly hatched larvae of the two species differed greatly in size and Water content of the yolk not in water content of the rest of the body (Tab. 3). The yolk-sac of the plaice was much larger than that of the herring. Furthermore, plaice yolk contained 93% water, while herring yolk contained 83% water. Thus herring larvae lack a yolk-sac buoyancy organ. Instead, they decrease their density by absorbing water as eggs and larvae until buoyant.
In the herring, there was increase in sodium and potassium content with increase in water content (Fig.2 and 5). A surprising result of the ion determination was the persistent difference between the two species. Sodium and potassium content at the middle stage of egg development was respectively 260 - 320 and 7.5 - 14 in the herring, and 87 - 117 and 26 - 44 m mol/kg in the plaice. In the newly hatched herring larvae, these were 290 and 12; in the plaice, 150 and 254 mmol/kg. Lipid and protein content, which contribute little to buoyancy, decreased linearly throughout egg and larval development in both species (Fig. 3 and 6). The lipid and protein content during egg development declined by about 26% and 11% for the herring, and 19% and 7% for the plaice. By PNR (the point-of-no-return, Blaxter and Hempel, 1963), the herring larvae had consumed 50-55% of the lipid and 32% of the protein present at hatching. In the plaice, these figures were 35% and 38%. |
| Key words: Herring, Plaice, Egg, Yolk-sac larva, Development, Biochemical changes |
