The pharmacokinetics of florfenicol were studied in healthy and vibriosis-infected large yellow croaker (Pseudosciaena crocea) following administration of a single oral dose of 20 mg·kg −1 at 25±2 o C. After oral administration, florfenicol levels in tissues (liver, kidney, muscle, serum, and skin) were analyzed using high-performance liquid chromatography. A two-compartment open model was used to describe the pharmacokinetics of florfenicol following oral administration. Compared to the healthy group, the absorption rate of vibriosis-infected fish significantly decreased, peak-time (T max ) delayed, maximum concentration (C max ) declined, total body clearance decreased, the elimination half-life (T 1/2β ) was extended, and the area under the curve increased. These results indicate that a 20 mg·kg −1 oral dose of florfenicol administered once daily continuously for 4 or 5 days can be used for the treatment of Vibrio alginolyticus infection in large yellow croaker (Pseudosciaena crocea).

Large yellow croaker, Pseudosciaena crocea, is an important cultured marine fish species (Jian & Wu, 2003). The yield of large yellow croaker is the highest among all cultured marine fish in China all year round. In 2019 alone, the yield of large yellow croaker reached 225.5 thousand tons (data from China Fishery Statistical Yearbook). The large yellow croaker industry occupies a pivotal position inChina's mariculture industry. However, with the expansion of breeding density and the deterioration of environmental conditions, diseases occur frequently, especially bacterial diseases, such as those caused by Vibrio parahaemolyticus, Vibrio harveyi and Pseudomonas