稀有鮈鲫仔鱼的摄食和耐饥饿能力

FEEDING AND STARVATION TOLERANCE OF THE YOLK-SAC LARVAE OF GOBIOCYPRIS RARUS

  • 摘要: 研究了室养条件下稀有的鮈鲫的摄食和耐饥饿能力。结果表明,仔鱼一般在孵出后1.5d-2d开口摄食,此时卵黄囊容量约从初孵时的0.1降至0.03mm3以下,在其后1-1.5d卵黄物质消耗殆尽;饥饿仔鱼的初次摄食率变化型式为:开始较低,然后迅速升高,约在卵黄吸尽时达到最高,最高初次摄食率为100%,保持在80%以上的时间为5d;持续饥饿或延迟开始摄食时间对仔鱼的生长、发育、存活有深刻的影响,饥饿仔鱼全长负生长及饥饿体征明显;初孵仔鱼持续饥饿8-10d达不可逆点(PNR),饥饿仔鱼在PNR前1.5d时存活率低于50%,在PNR后2d全部死亡。

     

    Abstract: Eleven batches of yolk-sac larvae of Gobiocypris rarus were reared at 25±1℃ to study the feeding ability and starvation tolerance.The time to initial feeding and to the point-of-no-return (PNR, when 50% larvae are no longer strong enough to feed) was determined, and characters of development both on fed and unfed larvae were observed.The larvae began to feed on 1.5-2d after hatching, when the yolk volume was less than 0.03mm3 (0.1 when hatching).The initial feeding rate usually reached its peak in 1-1.5d when the yolk became exhausted.The highest feeding rate was 100%, and the time keeping the rate above 80% was 4 to 5 days.Starvation has disadvantageous effect on growth, development and survival.Not only the starved larvae occurred in negative growth, but also showed a series of characters, including decrease in size of various organs, the pectoral angle etc.The PNR was 8 to 10 days after hatching, with a mode of 9.On 1-2d before PNR, the survival rate of starved larvae became lower than 50 %, while all unfed larvae died within 2 days after PNR.

     

/

返回文章
返回