Effects of probiotic additive feeding on water quality and algal growth potential in a culture of the carp Cyprinus carpio

In order to mitigate the effects of water pollution in the aquaculture farms, the results of probiotic trials in cultures of the carp Cyprinus carpio were preliminarily conducted. The culture experiments were carried out for 45 days in the Summer and Autumn of 1998. Two outdoor concrete thanks, 3 x 2 x 1.5m each, were employed. Twelve fish (average body weight, 52.8g) were cultured in each thank. The fish were fed on a mixed diet of 98% eel mash and 2% probiotics. "Amakusa-PX" (tank A) and 100% of eel mash (tank B, control). The water contents (e.g., ammonium-N, nitrite-N, nitrate-N, phosphate-P) were determined every three of four days. Fish body weight was measured at the beginning and the end of the culture experiments. The water color in tank A fed Amakusa-PX was more green than that of tank B. The population densities of Chlorella spp. in tank A and tank B were 85±53×10｀6´ cells/ml and 52±35×10｀6´ cells/ml, respectively. The final average body weight of fish in tank A was 30% higher than that of fish in tank B. Levels of ammonia-N in tank A were 30% lower than in tank B. It is concluded that the ecological energy flow were more efficiently promoted than in the control, tank B.記事区分：原