<;P>;PROBLEM TO BE SOLVED: To provide functional fish culture feed to be administered as general feed, containing no harmful substance to remain and be accumulated in fish body, preventing infectious disease caused by Flavobacterium bacteria and capable of preventing damage of fillet, and to provide an evaluation method of preventive effect of infectious disease caused by Flavobacterium bacteria through administration of the functional fish culture feed. <;P>;SOLUTION: The functional fish culture feed contains extract of Vitis spp. seeds and &beta;-1,3/1,6-glucan and is used for preventing infectious disease caused by Flavobacterium bacteria. <;P>;COPYRIGHT: (C)2006,JPO&NCIPI