池塘养殖异育银鲫寄生黏孢子虫的种群动态

THE POPULATION DYNAMICS OF MYXOSPOREAN PARASITES IN POND-REARED ALLOGYNOGENETIC GIBEL CARP,CARASSIUS GIBELIO

研究对湖北洪湖地区一养殖池塘的异育银鲫开展了黏孢子虫的流行病学调查,以利于黏孢子虫病的综合防治。发现异育银鲫中寄生了4种黏孢子虫,分别为多涅茨尾孢虫(Henneguya doneci Schulman 1962)、住心碘泡虫(Myxobolus hearti Chen,1998)、瓶囊碘泡虫(Myxobolus ampullicapsulatus Zhao 2008)和尾孢虫未定种(Henneguya sp.)。鳃寄生的多涅茨尾孢虫在不同月份中感染率有显著差异(P<0.05),在4—6月未见包囊,7—9月感染率突增,明显高于其他月份;多涅茨尾孢虫包囊的平均丰度与其感染率的变化趋势相同,不同月份间,多涅茨尾孢虫平均丰度在统计学上差异显著(P<0.05);多涅茨尾孢虫平均包囊直径从7月至12月逐渐增大,随后月份逐渐减小,不同月份间,多涅茨尾孢虫平均包囊直径在统计学上差异显著(P<0.05);在不同的鳃片之间,多涅茨尾孢虫平均感染强度差异不显著(P>0.05),但第四片鳃的平均感染强度明显要高于其他鳃片。鳃寄生的瓶囊碘泡虫只在3—6月发现感染,感染率6月最高;心脏寄生的住心碘泡虫全年都发现感染,在不同月份中感染率差异不显著(P>0.05);膀胱寄生的尾孢虫未定种除了8月,其他月份均有感染,1—4月的感染率显著高于其他月份(P<0.05)。

Myxosporean species are one of the major parasite pathogens that hinder the allogynogenetic gibel carp aquaculture. The epidemiologic survey of the myxosporean species in allogynogenetic gibel carp should help with the control of myxosporidiosis. We found 4 types of myxosporean species -- Henneguya doneci, Myxobolus hearti, M. ampullicapsulatus, and H. sp. -- during the investigation of the myxosporean-infected pond-reared allogynogenetic gibel carp in Honghu city of Hubei province. The infection rate of gill-infecting H. doneci varied significantly in dif-ferent months (P<0.05). The plasmodia of H. doneci were absent from April to June. But its infection rate increased dramatically from July and reached to the peak in September, and then gradually decreased from October to March of the following year. The mean abundance of the plasmodia of H. doneci showed a similar trend and also varied remarka-bly in different months (P<0.05). The mean diameter of the plasmodia of H. doneci gradually increased from July to December, and then decreased in January of the following year. The differences in the mean diameter between months were statistically significant (P<0.05). Moreover, the mean infection intensity of the H. doneci plasmodia on the fourth gill bar was apparently higher than that on the other gill bars. The plasmodia of gill-infecting species, M. ampullicap-sulatus, were present only from March to June, and its infection rate gradually increased to its peak value in June. The plasmodia of heart-infecting species, M. hearti, were present in the entire year, but its infection rate was not signifi-cantly different between months (P>0.05). Henneguya sp. was found to infect the urinary bladder of fish in the whole year except for August, and its infection rate was relatively higher from January to April.