不同营养供给模式对中华绒螯蟹生长及肝胰腺白化症发病率的影响

Effects of different feeding models on growth of Chinese mitten crabs and their relation to its incidence of hepatopancreas albinism

采用正交设计法L9（3^4）将水体水草覆盖率、活螺蛳投放量、饵料中动物性饵料比例、投饵方式等4个因子设计成9种不同营养供给模式,对中华绒螯蟹生长指标及其肝胰腺白化症发病率进行比较研究。每个模式设3个重复,以540只初始体重为每只（9.67±0.47）g的二龄中华绒螯蟹为实验对象,在东太湖中华绒螯蟹围养区的27个独立网围（6m×5m×2.5m）中进行为期240d的养殖实验。结果表明,不同的营养供给模式显著影响中华绒螯蟹生长及其肝胰腺白化症发病率,其中模式4的养殖效果最好,肝胰腺白化症发病率最低。方差分析结果显示,4个因子对中华绒螯蟹生长及其肝胰腺白化症发病率影响作用顺序为：水草覆盖率〉动物性饵料比例〉投饵方式〉螺蛳投放量。将4个因子与养殖蟹肝胰腺白化症发病率、增重倍数、肥满度、回捕率、饵料系数等参数进行回归分析,表明水体水草覆盖率、饵料中动物性饵料比例、投饵方式等因子与中华绒螯蟹肝胰腺白化症发病率及生长指标关系密切,得出中华绒螯蟹养殖较适宜的营养供给模式为：水草覆盖率为73.95%、动物性饵料比例为56.15%～62.22%、投饵方式为全程投喂7.5%～5.0%、螺蛳投放量为5578.05kg·hm^-2。

The orthogonal design method of table L9 （3^4） was adopted to construct nine different feeding models for Chinese mitten crabs （ Eriocheir sinensis ） based on four factors, that is, the coverage of aquatic plants, the input of live snail, the ratio of animal based feed to total feed and different feed casting patterns, and their threelevels. 540 two-year old Chinese mitten crabs with initial body weight of （9.67 ± 0.47 ） g were fed in 27 separate pens （6 m × 5 m × 2.5 m） in the raising areas of east Taihu Lake for 240 days following these feeding models with three replicates, and the effects of these feeding models on growth of Chinese mitten crab and their relation to its incidence of hepatopancreas albinism were comparatively analyzed. The results showed that different feeding models exerted significant effects on its growth and hepatopancreas albinism incidence. Among these feeding models, model Ⅳ produced the best raising results and brought the lowest incidence. The results from variance analysis indicated that the effects of the four factors on growth and albinism incidence were listed in the order of importance as： the coverage of aquatic plants 〉 the ratio of animal based feed to total feed 〉 the feed casting patterns 〉 the input of live snail. A statistical regression analysis was conducted based on the four factors, together with parameters of albinism incidence, weight gain, fullness, capture rate, and feed conversion efficiency. The results confirmed that the coverage of aquatic plants, the ratio of animal based feed to total feed, and the feed casting patterns had close relations to the albinism incidence and growth of Chinese mitten crabs. It is suggested that the feeding model suitable for the raising of Chinese mitten crabs be characterized as follows ： the coverage of aquatic plants was 73.95 %, the animal based feed accounted for 56.15 % - 62.22 % of total, the feed was given during whole growth and developmental stages and in the amount of 7.5 % - 5.0 % of the crab weight, the amount of live snail input was 5578.05 kg·hm^-2.