Health status of the nase (Chondrostoma nasus) in breeding farms from the Jihlava River basin.

摘要

This study was conducted to compare the health status of two fish farms in the Jihlava River basin that differ mainly in the intensity of rearing of the nase fry and in water sources. The health condition of fry from hatching to expedition at the age of one year during rearing were observed. Four species of parasites (Ambiphrya ameiuri, Apiosoma piscicolum, Trichodina sp. and Diplostomum spathaceum) were observed infesting the fishes and Aeromonas hydrophila was isolated by bacterial culture. In both breeding facilities, the intensity and prevalence of Ambiphrya ameiuri increased during the summer. The state of health and its development including the recognized infection was similar in both farms. Immunological indicators such as differential white cell count, absolute white cell count and the oxidative burst during autumn were evaluated in the fry samples. Although fry from both farms had similar health condition, the results on immunological indicators showed that fry from farm I were more exposed to the effects of stressors. The results of immunological indicators in fry from farm II and brood fish from the Jihlava River showed differences, which could be caused by a variety of stress factors having different effects on the immune system of these two fish categories. The environment significantly affects the immunity of juvenile as well as brood fish. It reflects in the different levels of immunological indicators in the fry from two farms, as well as in the fry and brood fish from the river.