A STUDY ON TOXIN OF Edwardsiella ictaluri IN STRIPED CATFISH (Pangasianodon hypophthalmus) AND GROWTH PERFORMANCE AT THE FRY STAGE OF 45 DAYS OLD
Tóm tắt
Bacteria Edwardsiella ictaluri is a major pathogenic bacterium threatening aquatic species and seriously affecting the aquaculture industry globally. Previous studies have focused on analyzing bacteria's pathological signs and virulence on pangasius fingerlings. However, research on the virulence and pathogenicity of Edwardsiella ictaluri in the striped catfish at the fry stage is still limited. Therefore, this study was carried out to evaluate the pathogenicity and virulence of Edwardsiella ictaluri bacteria on 45-day-old striped catfish (Pangasianodon hypophthalmus) through infection experiments. A total of 1,170 striped catfish were subjected to infection at concentrations of 0, 103, 104, 105, and 106 CFU/mL by the immersion method. After nine days of infection, the results showed that the cumulative mortality of striped catfish ranged from 3.08 - 100%. The lethal dose (LD50) of E. ictaluri on striped catfish at the fry stage was 7.59 × 104 CFU/mL. At all concentrations, the growth parameters (weight gain, percentage specific growth rate, daily weight gain, length gain, percentage specific growth rate length, daily length gain of striped catfish treatment) were reduced compared with the control group.