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Evaluation of Difloxacin for Shrimp Aquaculture: In Vitro Minimum Inhibitory Concentrations, Medicated Feed Palatability, and Toxicity to the Shrimp Penaeus vannamei
Author(s) -
Park Eric D.,
Lightner Donald V.,
Williams Rodney R.,
Mohney Leone L.,
Stamm John M.
Publication year - 1995
Publication title -
journal of aquatic animal health
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.507
H-Index - 52
eISSN - 1548-8667
pISSN - 0899-7659
DOI - 10.1577/1548-8667(1995)007<0161:eodfsa>2.3.co;2
Subject(s) - shrimp , palatability , biology , litopenaeus , zoology , toxicity , food science , veterinary medicine , toxicology , fishery , medicine
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 approximately 5, 10, and 20 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, whereas 400 mg/kg of feed or more may be unpalatable and toxic to shrimp.