Evaluation of the efficacy of enrofloxacin in rainbow trout (Oncorhynchus mykiss) following experimental challenge with Yersinia ruckeri

Abstract

Background: Use of enrofloxacin in trout farms is reported, especially for the treatment of yersiniosis, albeit various dosing regimens have been used. Therefore, optimal doses should be investigated. Methods: Five groups of 15 fish were challenged with Y. ruckeri. Two days later, three groups received feed containing enrofloxacin (ENR) at 1, 2.5 and 5 mg/kg fish respectively, during 7 days; one group received a single intraperitoneal injection of ENR at 10 mg/kg; and one group was left untreated. On day 15, surviving fish were euthanized. Results: All fish survived in the group treated by injection, compared to 53%, 60% and 40% of the fish treated with 1, 2.5 and 5 mg/kg oral ENR, respectively, and 53% in the infected untreated group. Conclusion: A single intraperitoneal injection of ENR at 10 mg/kg seems more relevant than repeated oral administrations. The ENR oral doses used in trout farms should be revised.

The Combination of β-Glucan and Astragalus Polysaccharide Effectively Resists Nocardia seriolae Infection in Largemouth Bass (Micropterus salmoides)

“…As confirmed by previous studies, enrofloxacin, administered at a dose of 10 mg/kg of body weight, effectively controlled mortality and treated francisellosis in juvenile Nile tilapia (Oreochromis niloticus L.) [46]. Another study showed that feeding enrofloxacin at a dose of 2.5 mg/kg improved the survival rate of rainbow trout infected with Yersinia ruckeri [47].…”

Population pharmacokinetics/pharmacodynamics modelling of enrofloxacin for the three major trout pathogens Aeromonas salmonicida, Flavobacterium psychrophilum and Yersinia ruckeri

“…(i) the potential non-linearity of PK absorption processes, e.g. with a saturable absorption at these doses; (ii) the toxicity at this dose range is not well known for fish; (iii) the palatability of food is probably a limiting factor (Hsu et al, 1994;Toften and Jobling, 1997), as already observed for sick animals (Rostang et al, 2021). Therefore, based on the MIC distribution of A. salmonicida of our study with ~70% of isolates having a MIC ≥ 0.25 µg/mL (figure 1), enrofloxacin does not seem to be an antibiotic of choice for the treatment against this bacterium.…”

“…However, in the context of metaphylaxis, which is the most frequent use of antimicrobial in fish production (Lulijwa et al, 2020), the early initiation of an enrofloxacin treatment for the majority of fish would limit the influence of the infection on food intake and on the PK of enrofloxacin, while treating a rather low initial bacterial load. The use of other routes of administration, such as the intramuscular or the intraperitoneal route (as in vaccination campaigns) could be an alternative to the oral route, allowing better inter-individual reproducibility, and ensuring a sufficient dose to each diseased fish (Rostang et al, 2021).…”

“…Curiously, the variability associated with PK parameters (clearance, bioavailability) and PD parameters (in terms of MIC) has not really been explored although it is a major influencing factor that must be taken into account to obtain optimal dosing (EMA, 2018). Moreover, a recent evaluation of the efficacy of enrofloxacin in rainbow trout following an experimental challenge with Y. ruckeri showed that a treatment based on oral doses from 1 to 5 mg/kg in feed for 7 days was insufficient (Rostang et al, 2021).…”

Pharmacokinetics, withdrawal period and risk assessment of enrofloxacin in the northern snakehead (Channa argus) following bath administration

“…It is widely used in aquaculture in view of its broad spectrum antibacterial activity and excellent pharmacokinetic characteristics (Lashev et al., 2015). ENR has been proved to have good antibacterial activity against most aquatic pathogens such as Aeromonas (Uney et al., 2021), Flavobacterium (Van Vliet et al., 2017), yersiniosis (Rostang et al., 2021), and Vibrio (Roque & Gomez‐Gil, 2003), and it is active at low concentrations, compared with other classes of antimicrobial agents (Langston et al., 2010). In aquatic animals, the main active metabolite of Enrofloxacin is ciprofloxacin (CIP).…”