title: Effectiveness of aquaflor (50% florfenicol) to control mortality associated with Streptococcus iniae in freshwater-reared subadult sunshine bass.
abstract: We conducted a field trial to evaluate the effectiveness of Aquaflor (50% florfenicol) for controlling mortality associated with Streptococcus iniae in freshwater-reared subadult sunshine bass (female white bass Morone chrysops X male striped bass M. saxatilis). Bacterial samples collected from moribund fish representing a reference population were presumptively identified microbiologically and were later confirmed to be S. iniae by biochemical characterization and polymerase chain reaction. The trial comprised a 1-d acclimation period, 10-d treatment period, and 14-d posttreatment period. During the treatment period, Aquaflor-medicated feed was administered to treated tanks (N = 3) at a target dose of 10 mg of florfenicol x kg of fish(-1) x d(-1), and nonmedicated feed was administered to control tanks (N = 3). At the end of the posttreatment period, mean (+/- SD) cumulative mortality in treated tanks (9 +/- 11%) was significantly (P = 0.040) less than that in control tanks (52 +/- 13%). Analysis of medicated feed samples revealed that treated tanks had received an actual dose of 8.3 mg florfenicol x kg fish(-1) x d(-1) (83% of target). No florfenicol was detected in control feed samples. Although the actual florfenicol dose administered to treated tanks was less than the target dose, the trial was accepted by the U.S. Food and Drug Administration Center for Veterinary Medicine as demonstrating the efficacy of Aquaflor to control mortality associated with S. iniae in cultured sunshine bass populations.
authors.affiliation: U.S. Fish and Wildlife Service, Aquatic Animal Drug Approval Partnership Program, 4050 Bridger Canyon Road, Bozeman, Montana 59715, USA. jim_bowker@fws.gov
authors.forename: James D
authors.initials: JD
authors.lastname: Bowker
authors.forename: Vaughn E
authors.initials: VE
authors.lastname: Ostland
authors.forename: Daniel
authors.initials: D
authors.lastname: Carty
authors.forename: Molly P
authors.initials: MP
authors.lastname: Bowman
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D017756:Aquaculture; D001492:Bass; D005393:Fish Diseases / Q000188:drug therapy* / Q000382:microbiology; D005618:Fresh Water; D013290:Streptococcal Infections / Q000188:drug therapy / Q000662:veterinary*; D013291:Streptococcus / Q000145:classification*; D013839:Thiamphenicol / Q000031:analogs & derivatives* / Q000627:therapeutic use; D013997:Time Factors
chemical_list: D000900:Anti-Bacterial Agents; C035534:florfenicol; D013839:Thiamphenicol