earticle

영어

In South Korea, frog farming has been permitted to protect Mountain brown frogs which continuously declining and have used as traditional dish resources. Despite of various breeding attempts over last 10 years, successful farming are still rare largely due to the lack of appropriate food items and poor disease managements. This study was conducted to provide useful information on appropriate density and temperature farming conditions to reduce potential pathogens in frog farms. Our study first explores the effects of different temperature and density treatments on the growth and the time to metamorphosis of Rana dybowskii tadpoles. Second, we determined how those two treatments affect the number of bacterial and fungal colonies on the skin and in the liver and heart of metamorphosed juveniles. Our results showed that the temperature treatment affected the growth of tadpoles and the time to metamorphosis unlike the density treatment. The snout-vent length was longer and the time to metamorphosis was greater in low temperature group than those in other temperature groups. Temperature treatment also induced significant differences in the number of bacterial and fungal colonies detected in the examined organs. The number of bacterial and fungi colonies was higher in ambient and low temperature groups than those in the high temperature and field-control group for the three organs. Density treatment showed significant difference only in the number of bacterial colonies. Medium and high density treatment groups had more bacterial colonies than low treatment group and field-control group commonly in the three organs. Our results suggest that 1) low density (10 tadpoles / 20L water) could be better for farming to reduce potential bacterial diseases, 2) low temperature (1℃ below than ambient temperature) might be selected for bigger metamorphosed juveniles, but 1℃ higher temperature than ambient temperature could be better to manage potential bacterial and fungal diseases.