Citrus microcarpa Extract as Immunostimulator in Controlling Edwardsiellosis in African Catfish Culture

Abstract

This study was described Citrus microcarpa extract as an antimicrobial agent in controlling edwardsiellosis in African catfish culture. Edwardsiellosis due to Edwardsiella tarda was recognized as a problem in African catfish culture and may lead to mass mortality of the cultured fish. Many antibiotics were no longer effective to control this bacterial disease. Therefore, this study was carried out to investigate the potential of C. microcarpa extract to overcome this bacterial disease problem. The experimental fish were fed with medicated feed at three different concentrations (1 g kg-1; CM-1, 2 g kg-1; CM-2 and 4 g kg-1 of fish) of C. microcarpa extract for one week before they were intraperitoneally exposed to E. tarda. Enzyme linked immunosorbent assay (ELISA) was carried out to determine the value of antibody response to E. tarda in fish from group of fish that received medicated fish and the percentage of total cumulative mortality of the experimental fish were observed at the end of the experiment. The results showed that the value of antibody response to E. tarda in fish from group of fish which received medicated feed (CM-1, 0.148 ± 0.017 OD; CM-2, 0.143 ± 0.006 OD; CM-4, 0.163 ± 0.015 OD) were found significantly higher (P < 0.05) compared to fish did not received medicated fish (0.00 OD). Whereas, percentage cumulative mortality of fish from all groups of fish received medicated feed (CM-1, 20.0 ± 10.0 %; CM-2, 16.7 ± 5.8 %; CM-4, 16.7 ± 5.8 %) were found significantly lower (P < 0.05) compared to group of fish did not received medicated feed (56.7 ± 5.8 %). The findings of the present study indicated the huge potential of C. microcarpa extract as natural antimicrobial agent for aquaculture use.