抗迟缓爱德华氏菌病牙鲆家系的筛选与分析

牙鲆(Paralichthys olivaceus)养殖病害日益严重,迟缓爱德华氏菌(Edwardsiella tarda)是牙鲆养殖中的主要致病菌,带来了极大的经济损失,为了培育出对该病抵抗能力强的牙鲆新品种,2014年4–6月间,利用我们长期以来建立和筛选出来的牙鲆抗病群体和家系的亲鱼,通过杂交,自交,雌核发育建立47个家系,9–10月间,对其中39个家系进行感染实验,先用少量鱼进行预实验摸索出半致死浓度,然后再进行正式感染实验,感染数量为每个家系80尾。各家系的存活率范围为1.19%~51.19%,最终平均存活率为20.29%,认为存活率高于30%的7个家系为抗病力强家系,存活率在20.29%~30%的9个家系为抗病力一般家系,平均存活率以下的23个家系为抗病力弱家系。1406#家系抗病力最强,它为1005#家系的自交后代,而其他抗病力强家系也大多是1005#、09104#、0915#的后代。而09104#为0768#的后代,并且0768#抗鳗弧菌病能力强。1005#为韩国群体自交后代,0915#为韩国群体和日本群体杂交后代。这些抗病力强的牙鲆可以作为新品系进行推广养殖,可望减少牙鲆腹水病发生。

Screening for resistance to Edwardsiella tarda in different families of Japanese flounder, Paralichthys olivaceus

<i>Edwardsiella tarda</i> is a significant pathogenic bacterium that causes considerable economic losses in flounder aquaculture. We created 47 flounder families using parental fish resistant to <i>E. tarda</i> and screened them long term through cross-fertilization, self-crossing, and gynogenesis experiments during April-June 2014. We infected 39 flounder families with <i>E. tarda</i> from June-October. The half lethal bacterial concentration was determined to be 80 in each family using a small number of flounder in a preliminary experiment. Survival rate was 1.19%-51.19% (mean, 20.29%). Seven families with survival rates >30% were most able to resist <i>E. tarda</i>; the nine families with survival rates of 20.29%-30% had normal resistance to <i>E. tarda</i>; and the 23 families with survival rates <20.29% were least resistant to <i>E. tarda</i>. Family 1406 had the best resistance, which was self-crossed with 1005. The families with the best resistance were all descendants of families 1005, 09104, and 0915. Family 09104 was a descendant of family 0768, which was resistant to <i>Vibrio anguillarum</i>, and was self-crossed with family 1005 and a Korean group. Family 0915 was cross-fertilized with Korean and Japanese groups. These disease-resistant flounder could be popularized as new strains to reduce the occurrence of virulent ascitesosis disease.