Location: Aquatic Animal Health ResearchTitle: Parasite treatment reduced Flavobacterium columnare infection in tilapia
Submitted to: Global Aquaculture Advocate
Publication Type: Popular Publication
Publication Acceptance Date: 10/20/2015
Publication Date: 10/30/2015
Citation: Xu, D., Shoemaker, C.A., Zhang, D. 2015. Parasite treatment reduced Flavobacterium columnare infection in tilapia. Global Aquaculture Advocate. November/December:18-19.
Technical Abstract: Bacterium Flavobacterium columnare and parasite Trichodina are common pathogens of cultured fish. The authors conducted a study to evaluate whether treatment of Trichodina parasitized tilapia with formalin would improve fish survival and reduce F. columnare infection in fish. Tilapia parasitized by Trichodina were divided into 3 groups and each group received one of following treatments: 1) no parasite treatment, 2) treated with 150 mg L-1 formalin bath for 1 h, and 3) treated twice with 150 mg L-1 formalin bath for 1 h each at 2 day intervals. All fish were then exposed to F. columnare by immersion challenge. The tilapia not treated with formalin showed significantly higher mortality (37.5%) than those treated with formalin (less than or equal to 16.7%) after exposure to F. columnare. Fish treated twice showed lower mortality (6.37%) than those treated only once (16.7%). The non-treated fish showed significantly higher number of F. columnare in gill, kidney and liver compared to those treated with formalin following exposure to F. columnare. The bacterial load of non-treated fish was 12 fold higher than those treated once with formalin or 39 fold higher than those treated twice with formalin. This study demonstrated that formalin treatment for Trichodina reduced F. columnare bacterial infection and subsequently reduced fish mortality.