草鱼体脂性状的变异特征及相关性

为探究草鱼体脂性状的变异特征及相关性,采用数理统计方法对296尾17月龄草鱼的15个数量性状指标进行综合分析评价。结果显示,草鱼体脂性状(腹脂指数IPF、肝胰脏粗脂肪含量HLC、肌肉粗脂肪含量MLC)具有丰富的变异特征,变异系数范围为21.30%～47.04%。相关分析发现,草鱼3个体脂性状之间呈现显著正相关,表明草鱼脂质沉积在不同组织中具有一定的同步性。进一步的因子与聚类分析显示,观测的15个草鱼数量性状大致分为4类,包括体型因子、体尺因子、脏器指数因子和体脂含量因子,其中IPF归属于脏器指数因子,HLC和MLC二者组成体脂含量因子。多元统计分析发现,草鱼形态性状对3个体脂性状变异的解释量范围为7.45%～24.83%,相较而言,矢状面体型SS可在一定程度上预测体脂性状。研究表明,草鱼体脂性状具备较大的选育潜力,其中IPF整体显示出较好的关联性,可作为代表性目标性状用于育种实践。本研究为草鱼体脂性状选择育种提供了重要参考依据。

Phenotypic variability and correlation analysis of lipid traits in grass carp (Ctenopharyngodon idella)

Grass carp (Ctenopharyngodon idella) is an important economic freshwater fish in China. Under intensive aquaculture conditions, the farmed grass carps often display excess fat accumulation, such as fatty liver, rotund shape and increased body lipid content. To evaluate the possibility of genetic improvement, this study estimated the phenotypic variability and correlation of lipid traits in C. idella. A total of 15 quantitative traits of 17 month-old C. idella among 296 individuals were analyzed by mathematical statistical methods. The results showed that intraperitioneal fat index IPF, hepatopancreas lipid content HLC and muscle lipid content MLC had high variation in C. idella, and the phenotypic variation coefficients ranged from 21.30% to 47.04%. Correlation analysis showed that there was a significant positive correlation among the three lipid traits, suggesting that the process of lipid deposition has a certain synchronization in different tissues of C. idella. Furthermore, factor and cluster analysis revealed that the observed 15 quantitative traits were roughly divided into 4 categories:body shape factor, body size factor, organ index factor, and body lipid content factor. IPF belonged to organ index factor, while HLC and MLC formed body fat content factor together. In addition, multivariate statistical analysis showed that the explanation degree of morphological traits on the variation of the three lipid traits ranged from 7.45% to 24.83%. By contrast, sagittal shape SS can, to some extent, predict body lipid traits. In summary, the lipid traits of C. idella have great potential for genetic improvement, and IPF would be an attractive character as breeding target. This study provided important reference for genetic improvement of lipid traits in C. idella.