维氏气单胞菌拮抗酵母菌Wickerhamomyces anomalus HZJ8的筛选及应用研究OA

To develop a yeast preparation capable of both promoting growth and boosting disease resistance,in this research,a yeast strain,HZJ8,exhibiting significant in vitro antagonistic activity against Aeromonas veronii(a major pathogen causing bacterial septicemia in fish),was isolated from the intestine of crucian carp(Carassius auratus).Taxonomic identification confirmed that HZJ8 belongs to the Wickerhamomyces anomalus group.Systematic evaluation of its culture conditions,safety,tolerance to adverse substances,and antagonistic stability revealed that W.anomalus HZJ8 did not possess hemolytic properties and has robust environmental adaptability and antagonistic stability.In fish trials,compared with regular feed,dietary supplementation with HZJ8 yeast significantly enhanced the weight gain rate(increased by 85.6%,P<0.05)and specific growth rate(increased by 78.4%,P<0.05)of C.auratus after 14 days.Challenge tests demonstrated that HZJ8 feeding effectively increased the survival rate of C.auratus infected with A.veronii.Concurrently,HZJ8 significantly elevated the activity of three resistance-related enzymes,including activity of superoxide dismutase(SOD),catalase(CAT),and acid phosphatase(ACP),in the fish liver(P<0.05).These findings indicated that W.anomalus HZJ8 possess dual functions in promoting growth and enhancing disease resistance of C.auratus.This study highlights the potential of fish-derived antagonistic yeast in controlling bacterial septicemia and provides theoretical and technical foundations for developing novel microecological agents in aquaculture.