利用低盐度养殖的凡纳滨对虾培育亲虾初探

以在盐度2~3条件下养殖至9月龄的凡纳滨对虾( Litopenaeus vannamei )成虾为材料, 研究低盐度养殖对虾在不同盐度驯养条件下的繁殖性能, 以期为利用低盐度养殖对虾培育亲虾提供科学依据。实验盐度梯度设置为1、8、15、23和30。雌虾经剪切单侧眼柄后进行促熟培育, 促熟期间的雄虾养殖水温控制在(27±0.5)℃, 雌虾水温控制在(28±0.5)℃。定期检查雌虾卵巢和雄虾精荚的发育情况, 采用精荚人工移植技术对不同盐度条件下培育的亲虾进行组合交配, 统计受精率和孵化率, 组织切片观察卵巢发育, 综合评价各实验组合的繁殖性能。结果表明, 在实验盐度梯度范围内, 雌虾卵巢都可发育成熟; 盐度1组雌虾成熟比例仅10%, 且全部死亡; 盐度8和15下发育成熟的雌虾达70%, 可正常产卵, 但产出的卵子受精率较低, 不能孵化出无节幼体; 盐度23和30下发育成熟的雌虾超过76%, 可正常产卵、孵化, 但孵化率较低。组织切片观察, 盐度8~30范围内各组雌虾卵巢发育无明显差异。在盐度8~30范围内, 凡纳滨对虾雄虾精巢都能够正常发育成熟, 但盐度30和23实验组的雄虾精巢发育速度明显快于盐度15和8组; 随着盐度的降低, 精荚发育成熟所需要的时间明显延长; 所有盐度实验组的精荚被移植后都可与卵子受精并孵化出无节幼体。

Preliminary studies on the broodstock maturation of Litopenaeus vannamei from low-salinity farming ponds

from low-salinity water farming ponds were carried out in laboratory. The prawns were reared under different salinities of 1, 8, 15, 23, and 30. Female unilateral eyestalks were sheared to promote maturation. The water temperature for the male shrimps was set at (27±0.5). The sexual development, spawning, fertilization, and hatching rates of the parents were investigated. The female gonads matured in all five salinity conditions; the proportion of mature females in salinity 1 was <10%; in salinities 8 and 15 it was 70%, with low fertilization and no nauplius; and it was >76% in salinities 23 and 30, with low hatching rates. Histological examination revealed that ovarian development did not differ among the 8−30 salinity conditions. The male gonads also matured normally, but the speed of sexual development in salinities 23 and 30 was significantly faster than that in salinities 8 and 15(<0.05). As salinity decreased, the time required for male shrimp maturation increased. The spermatophores were fertilized and nauplius hatched in all salinities.