Comparative Studies on The Efficiency of Neem Leaves Azadirachta indica and Flubendazole Treatment Against Diplectanum in Sea Bass Dicentrarchus labrax

Purpose Diplectanum is a life-threatening metazoan infecting the gills of Sea bass Dicentrarchus labrax causing a wide-ranging extensive economic loss in the aquaculture sector. This study has focused on verifying the most effective non-toxic dose of the Neem ( Azadirachta indica ) and (flubendazole) bath treatment on infested D. labrax fingerlings. Methods In the first phase of the experiment, a total of 180 apparently healthy fingerlings were subdivided into six groups for each treatment. The tested concentrations were 0, 50, 100, 150, 200, and 250 mg L −1 for A. indica and 0, 10, 20, 30, 40, and 50 mg L −1 for flubendazole. The second phase was conducted for one week in five groups for each treatment. The first group was untreated healthy. The remaining groups were infested and received different concentrations of 0, 50, 100, and 150 mg L −1 & 0, 10, 20, and 30 mg L −1 for A. indica and flubendazole, respectively. Results The most toxic dose exhibited high mortality rates at 200 & 250 and 40 & 50 mg L −1 for A. indica and flubendazole, respectively. In the second phase of the experiment, the most effective dose was 150 and 30 mg L −1 ; for A. indica and flubendazole, respectively. They demonstrated the lowest mortality rates 20.00 & 20.00 %, prevalence rates 43.33 & 23.33%, and mean parasitic intensities were 2.35 & 2.00 accompanied by the highest therapeutic efficacy value 67.85 & 74.6% for both treatments; respectively. Conclusion The most effective anthelmintic efficacy has been assigned for flubendazole and A. indica at 30 and 150 mg L −1 .