聚β-羟基丁酸酯对中国对虾(Fenneropenaeus chinensis)亲虾的繁殖性能和幼体发育的影响

Effects of Poly-β-Hydroxybutyrate on the Fecundity and Larval Development of Fenneropenaeus chinensis

采用单因子浓度梯度法,在中国对虾(Fenneropenaeus chinensis)的生长和产卵阶段,对健康的中国对虾亲虾投喂添加不同含量聚β-羟基丁酸酯(PHB)(0、0.5%、1.0%、2.0%、3.0%、5.0%)的饵料,以期探究不同含量PHB对中国对虾亲虾的繁殖性能和幼体发育的影响。实验周期为192 d,统计亲虾的死亡率、相对免疫保护率、增重率、特定生长率、性腺发育周期、产卵量、无节幼体的数量、孵化率及变态发育周期。结果显示,PHB对中国对虾亲虾的繁殖性能和幼体发育均有一定影响。随着PHB浓度的升高,死亡率呈先下降后上升趋势,而相对免疫保护率则呈现相反的变化趋势,其中,2.0%浓度组的死亡率最低,2.0%与1.0%浓度组差异不显著(P>0.05),但与其他浓度组相比均差异显著(P<0.05)。亲虾实验组平均体重高于对照组,2.0%浓度组、5.0%浓度组与对照组相比差异显著(P<0.05)。在性腺发育周期方面,对照组与实验组无显著性差异(P>0.05)。实验组产卵量和无节幼体数量的平均值高于对照组,其中,2.0%浓度组与对照组相比差异显著(P<0.05),但与其他实验组相比无显著差异(P>0.05)。对照组与各实验组在幼体的变态发育时间无显著性差异(P>0.05)。研究表明,PHB添加剂对中国对虾亲虾的繁殖性能和幼体发育具有促进作用,2.0%为最适浓度。

In the present study, Fenneropenaeus chinensis were fed artificial diets supplemented with different concentrations of poly-β-hydroxybutyrate （PHB： 0, 0.5%, 1.0%, 2.5%, 5.0% and 10.0%） during the grow-out and spawning period. The goal was to investigate the effects of PHB on the reproductive performance of parental shrimps and thereafter the development of the larval F. chinensis. This study used the single factor concentration gradient method. After 192 days, the mortality rate, relative immune protectionrate （RPS）, weight gain rate （WGR）, specific growth rate, gonadal development cycle, fecundity, the number of nauplii hatched and the timing of various stages of metamorphosis were compared. The results indicated that the PHB had mixed effects on the fecundity of parental shrimps and growth performance of larva. Compared with control group, with the increase of PHB concentrations, the mortality rate of the experimental groups exhibited downward trend followed by increases. By contrast, the RPS had an opposite trend, with the lowest mortality rate in 2.0% PHB group; and the differences were significant compared to other groups （P〈0.05） except for the 1.0% PHB group （P〉0.05）. The WGR of all the PHB supplemented groups was higher than the control group. Specifically, the WGR of the group supplied with 2.0% PHB was significantly higher than groups supplied with 0 and 5.0% PHB （P〈0.05）. But there was no significant difference in the gonadal development cycle among all groups （P〉0.05）. Fecundity and the number of nauplii hatched in the experimental groups were higher than the control group, but the significance was only found in the group supplemented with 2.0% PHB （P〈0.05）. In addition, there was no significant difference in the timing of the various stages of metamorphosis among all groups. Based on the results, it can be concluded that the PHB supplement could improve the fecundity and larval development in F. chinensis with the best dietary PHB concentration of 2.0%.