黑鲷(♀)×真鲷(♂)杂交子二代仔鱼早期发育及饥饿不可逆点

Study on larval early development and point of no return of hybrid F2 of Acanthopagrus schiegelii (♀)×Pagrus major (♂)

  • 摘要: 以黑鲷(Acanthopagrus schlegelii ♀)×真鲷(Pagrus major ♂)杂交子一代为亲鱼,于2017年4月在水温(21.8±0.4) ℃条件下,对自然受精、人工孵化获得的杂交子二代(F2)早期仔鱼进行发育观察,并就饥饿对仔鱼早期生长与存活的影响及不可逆点(point of no return,PNR)进行研究。结果表明,杂交F2初孵仔鱼全长(2.40±0.15) mm,仔鱼3日龄开口摄食,混合营养期4~5 d,7日龄全长增长到(3.95±0.04) mm,生长态势正常;杂交F2仔鱼开始摄食的初次摄食率及最高摄食率分别为45.8%及77.21%,6日龄时初次摄食率下降为29.83%,抵达PNR时间;饥饿仔鱼5日龄时负生长,全长与对照组有显著差异(P<0.05),6日龄时全长与对照组有极显著差异(P<0.01)。研究表明杂交F2早期仔鱼具有较好的生长态势;其开始投饵的最适时机应于仔鱼开口后的3 d内。

     

    Abstract: With the hybrid F1 Acanthopagrus schiegelii (♀) ×Pagrus major (♂) as parents, we analyzed the early development and point of no return (PNR) of hybrid F2 which were naturally fertilized and artificially incubated at the water temperature of (21.8±0.4) ℃ in April, 2017. The results show that the total length of the newly hatched larva was (2.40±0.15) mm, and the larva started feeding at 3 dah with the mixed feeding stage lasting 4−5 d. The yolk sac disappeared at 7 dah and the total length was (3.95±0.04) mm. The initial feeding rate and the highest feeding rate were 45.80% and 77.21%, respectively. The initial feeding rate dropped significantly to 29.83% at 6 dah and the PNR appeared. In the starvation group, the larvae experienced negative growth and had significant difference at 5 dah (P<0.05) and very significant difference at 5 dah (P<0.01) in the total length with the control group. It is indicated that the development of hybrid F2 larvae was good, and the optimum initial feeding time for the larvae was within 3 d after their mouths opened.

     

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