池塘养殖草鱼两性体质量生长差异研究

Differences in Body Weight Growth between Female and Male Grass Carp Cultured in a Pond

为探明池塘养殖条件草鱼两性体质量生长规律,采用电子芯片标记技术和解剖鉴定性别方法,追溯不同性别草鱼在7月龄、8月龄、12月龄、16月龄、20月龄和32月龄的体质量生长状况,运用独立样本t检验比较雌、雄草鱼体质量差异。试验结果表明,7～16月龄雌、雄草鱼体质量差异均不显著(P>0.05);20月龄雌鱼和雄鱼平均体质量分别为2659.09 g和2530.06 g,32月龄分别为4868.21 g和4418.11 g,雌鱼比雄鱼体质量分别增加了5.10%和10.18%,雌、雄差异达到显著和极显著水平(0.01<P<0.05和P<0.01)。运用Logistic、Gompertz和Von Bertalanffy 3种非线性模型对雌、雄草鱼体质量生长规律和生长曲线进行拟合,研究结果表明,3种非线性模型均能较好的描述雌、雄草鱼体质量生长规律,其中Logistic模型拟合效果更佳。体质量的最佳拟合参数的分析结果显示,雌、雄草鱼拟合精度(r^2)均为0.995,雌性草鱼和雄性草鱼的拐点月龄分别为19.73月龄和19.57月龄、拐点处体质量分别为2442.63 g和2220.13 g。研究结果有助于探明雌、雄草鱼在池塘条件下各自的生长模式,为草鱼单性品种选育和健康养殖提供参考。

Three hundred juveniles of grass carp ( Ctenopharyngodon idellus ) with body weight of 30 g sampled from 3 different geographical origins of grass carp population in Yangtze River System,respectively,were marked by electronic chip marker technique and reared in a 0.33 hm 2 pond. The body weight were measured in the marked male and female grass carp at age of 7,8,12,20 and 30 month old by anatomical identification and dissection and compared by Independent-Samples t -test to investigate the differences in body weight growth between female and male of grass carp cultured in a pond. The results showed that there were no significant differences in body weight between males and females at 7-16 months ( P >0.05). The females had body weight of 2659.09 g at 20 month old and 4868.21 g at 32 month old and the males 2530.06 g at 20 month old and 4418.11 g at 32 month old,5.10 % higher in female than that in male at 20 month old ( P <0.05) and 10.18 % higher in female than that in male at 32 month old ( P < 0.01 ). The fitting of nonlinear models Logistic,Gompertz,and Von Bertalanffy to growth data revealed that the weight growth of male and female grass carp was described by the three types of nonlinear models,with the best logistic model r 2 of 0.995. The inflection point was observed at 19.73 month old for females with body weight of 2442.63 g and 19.57 month old for males with body weight of 2220.13 g. The findings are helpful in understanding of the growth rhythm of male and female,and provide a reference for breeding management and selection of new varieties in grass carp.