Open AccessEfficacy of florfenicol for control of mortality associated with Flavobacterium columnare in tilapia
Author(s) -
Thinh H. Nguyen
Publication year - 2018
Publication title -
the journal of agriculture and development/the journal of agriculture and develoment/nông nghiệp và phát triển
Language(s) - English
Resource type - Journals
eISSN - 2615-949X
pISSN - 2615-9503
DOI - 10.52997/jad.10.04.2018
Subject(s) - florfenicol , tilapia , biology , aquaculture of tilapia , veterinary medicine , aquaculture , flumequine , fish farming , zoology , microbiology and biotechnology , fish <actinopterygii> , ciprofloxacin , fishery , medicine , antibiotics , enrofloxacin
The efficacy of florfenicol for control of mortality associated with Flavobacterium columnare was studied in tilapia. F. columnare T3-8/10 strain used for infection was tested for virulence by bath challenge to tilapia (body weight: BW 14 - 16 g) and antimicrobial sensitivity test. The results showed LD50 of this bacterial strain was 4.8×104 CFU/mL and it was sensitive to florfenicol. Experiment for control mortality caused by the bacterium in tilapia (BW 18 - 20 g) was designed with four treatments including negative control (uninfected fish), positive control, NT10 and NT15 (infected with LD50). Just after infection, fish in positive control, NT10 and NT15 treatments were treated with florfenicol at doses of 0, 10 and 15 mg/kg BW/day for 10 days, respectively, by feeding fish with medicated feed. Mortality of fish in positive control treatment after 14 days of infection was 54.0 ± 5.47% and statistically different in comparison with those in negative control, NT10 and NT15 treatments were 0.0, 3.0 ± 4.72 and 2.60 ± 2.51%, respectively (P < 0.05). Fish in NT10 and NT15 treatments were sampled for testing florfenicol residue in the flesh at day 1, 16, 20 and 24 after treatment. The results showed florfenicol residue levels in the flesh of sampled fish at all testing timepoints were significantly lower in comparison with the safe concentration lower than 1000 ppb regulated by the Ministry of Agriculture and Rural Development of Vietnam.