Standard in vitro minimum inhibitory concentrations (MICs) were determined for difloxacin and compared with the MICs of several other antimicrobials against a standardized battery of 13 gram-negative bacterial isolates associated with shrimp disease. The palatability and safety (toxicity) of difloxacin to the shrimp Penaeus vannamei were also evaluated during 15 d of medicated feeding at 1 × (100 mg/kg of feed), 2×, and 4× treatment levels to give doses of approximately5, 10, and20 mg difloxacin/kg body weight. A significant reduction (P < 0.05) in difloxacin-medicated feed palatability was noted in the 2× and 4× trials. However, differences were still acceptable, because more than 80% of the feeds were consumed in both treatments relative to the control diet. Shrimp mortality rates increased with difloxacin level from 7% for the control treatment to 20% for the 4× treatment. Differences in percent survival were not significant (P> 0.05)by the Williams test however, analysis of mean survival time indicated that difloxacin significantly (P ≤ 0.05) reduced survival time at the highest dose. Signs of animal stress, characterized by extreme lethargy, were noted in the 4× treatment. An actual therapeutic dose for difloxacin in penaeid shrimp is unknown; however, the 1× treatment (100-mg/kg) was acceptable with respect to both palatability and toxicity, where as 400 mg/kg of feed or more may be unpalatable and toxic to shrimp.
|Original language||English (US)|
|Number of pages||7|
|Journal||Journal of Aquatic Animal Health|
|State||Published - Jun 1995|
ASJC Scopus subject areas
- Aquatic Science