超大规格中华绒螯蟹繁殖性能和育苗效果评价

Evaluation on reproductive performance and breeding effect of super-sized Chinese mitten crab (Eriocheir sinensis)

摘要:

中华绒螯蟹（Eriocheir sinensis）人工繁殖过程中亲本规格差别较大,目前大多选用超大规格亲本繁育子代,尚不清楚超大规格亲本的生殖性能及其繁育效果,本研究以超大规格亲本（规格Ⅰ：雌体300 g,雄体400 g）为研究对象,以小规格亲本（规格Ⅱ：雌体150 g,雄体250 g）为对照,比较不同亲本规格对其生殖性能和胚胎质量的影响,并进一步讨论两种规格亲本的生态繁育效果。结果表明：（1）生殖性能方面,规格Ⅱ亲本在配对期间的抱卵率一直显著高于规格Ⅰ亲本,但两规格亲本的最终抱卵率接近；虽然规格Ⅰ亲本的抱卵量显著高于规格Ⅱ亲本,但亲本成活率、生殖力及生殖指数均显著低于规格Ⅱ亲本；两规格亲本在卵经、卵重及胚胎常规生化方面无显著差异。（2）就育苗效果而言,饵料投喂量在幼体培育期间呈先增后减的变化趋势,其中溞Ⅴ变态为大眼幼体期间明显饵料投喂量最高,且规格Ⅱ组幼体的饵料日投喂量整体高于规格Ⅰ组幼体；虽然规格Ⅰ亲本单蟹产苗量显著高于规格Ⅱ亲本,但单位面积产量显著低于规格Ⅱ亲本；此外,规格Ⅰ亲本所产大眼幼体的淡化率也低于规格Ⅱ亲本。综上,虽然超大规格亲本的抱卵量和单蟹产苗量显著高于小规格亲本,但超大规格亲本的抱卵速度、成活率及淡化率均明显低于小规格亲本,如何通过营养调控提高超大规格亲本的繁殖性能有待进一步研究。

Abstract:

The Chinese mitten crab （Eriocheir sinensis） is an important economic crab in China. It occupies an important position in the fishery economy, with an annual output value of more than 100 billion yuan. Although there are five E. sinensis varieties approved by China National Committee for Original and Improved Aquatic Species, they cannot fully meet the diversified needs of E. sinensis breeding industry. The breeding of super-sized E. sinensis broodstock has been a revolution in the crab industry since 2019. The use of offspring of super-sized broodstock for adult crab culture has indeed effectively improved the crab cultivation specifications. Super-sized broodstocks can produce a large number of eggs, and the offspring of super-sized broodstocks have obvious growth advantages at the juvenile crab stage and the adult crab culturing stage, and the price of megalopa bred by super-sized broodstocks is also relatively high. Therefore, nursery workers tend to use super-sized crabs as broodstocks for breeding work. However, in the artificial breeding process, the selection of broodstock weight of E. sinensis varies greatly. Now, it is popular to use super-sized broodstock to breed offspring, but the reproductive performance and breeding effect of super-sized broodstock are not clear. In this study, the broodstock of super-sized strains （Size Ⅰ： dam weight ≥300 g, sire weight ≥400 g） were used as the experimental object, and the broodstock with smaller size （Size Ⅱ： dam weight ≥150 g, sire weight ≥ 250 g） were used as the control group. The effects of broodstock sizes on reproductive performance and egg quality were compared, and the ecological breeding effects of these two strains were further discussed. The results showed that： （1） In terms of reproductive performance, the survival rate, fecundity and reproductive effort of Size Ⅰ broodstock were significantly lower than those of Size Ⅱ, and the egg production was significantly higher than that of Size Ⅱ； There were no significant differences in egg diameter, egg weight, moisture, crude protein, total lipid and ash contents. （2） In terms of breeding effect, the feeding amount for larvae showed a “low-high-low” trend during the breeding period, and the highest feeding amount was observed between Zoea Ⅴ and the megalopa stage. Although the seedling yield of single crab in Size Ⅰ was significantly higher than that of Size Ⅱ, the per unit area yield was significantly lower in Size Ⅱ broodstock, and the dilution ratio was also relatively lower in Size Ⅱ broodstock. In conclusion, although the super-sized broodstock exhibited significantly higher broodstock quantity and individual seedling yield compared to the small-sized parental stock, the super-sized parental stock demonstrated lower broodstock incubation rate, survival rate, and dilution rate compared to the small-sized broodstock. Further research is needed to explore how nutritional regulation can be utilized to enhance the reproductive performance of super-sized broodstock.