Best Treatment Practices Of Warmwater Fish Pathogens Using Feed Medicated With Aquaflor.Doc Subida Exitosa

Best Treatment Practices of Warmwater Fish Pathogens Using Feed Medicated with Aquaflor
10 September 2012
Patricia S.Gaunt, Mississippi state University looks at the best treatment practices of warmwater fish pathogens using feed medicated with Aquaflor (florfenicol). Taken from the MSD Animal Health 'Bacterial Disease in Warmwater Fish: New Strategies for Sustainable Control' proceedings.Introduction
Aquaflor® (florfenicol) is a fast-acting, palatable, broad-spectrum antibiotic provided as a feed premix. It is proven to be an effective and safe antibiotic for use in fish. To maintain the efficacy of this valuable antibiotic and obtain maximal benefit from feed medicated with Aquaflor, producers and diagnosticians must understand the rationale behind the label indications andthey must work cooperatively.

Aquaflor is approved for use in finfish in over 20 countries. Indications differ from country to country but include control of mortality due to diseases associated with the warmwater bacterial pathogens Edwardsiella ictaluri, Streptococcus iniae, Streptococcus agalactiae, Flavobacterium columnare, Francisella asiatica and Aeromonas hydrophila.

In theUS, the approval of Aquaflor for use in fish involved many experimental efficacy and safety studies required by the United States Food and Drug Administration, a US regulatory body. In the US, Aquaflor is currently approved for control of mortality due to enteric septicemia of catfish, furunculosis and coldwater disease in salmonids. Aquaflor®-CA1 (florfenicol) is conditionally approved for controlof mortality due to columnaris disease in catfish.

The objective of this paper is to explain the best practices for incorporating Aquaflor into overall disease management programs for warmwater fish production.
Efficacy Studies
In vivo and in vitro efficacy studies with Aquaflor have been conducted.

In vitro efficacy studies: The sensitivity of bacterial pathogens toflorfenicol (FFC) has been assessed by determining the minimal inhibitory concentrations (MIC) of FFC for bacteria from both experimental studies and from diagnostic specimens obtained from disease outbreaks on farms. This laboratory assay quickly determines the susceptibility of bacteria to drug.

MIC values for warmwater fish pathogens of interest are presented in Table 1. The values indicate thata wide variety of warmwater bacterial pathogens are susceptible to FFC. MIC values correlated with data from pharmacokinetic studies can be used to predict and validate the clinical performance of Aquaflor on farms.
Minimal Inhibitory Concentration (MIC) of Florfenicol in Bacteria Cultured from Catfish and Tilapia. The Values indicate that the Bacteria are Susceptible to the Antibiotic.
[pic]In vivo studies: Experimental Aquaflor efficacy studies in warmwater fish were conducted at a dose rate of 10 mg FFC/kg bodyweight against the pathogens E. ictaluri and F. columnare in catfish (Ictalurus punctatus) fingerlings. Aquaflor was highly efficacious (p < 0.001) when compared to controls (Figures 1 and 2).
Efficacy of Aquaflor Demonstrated by Reduced Mortality in Channel CatfishChallenged with E. Ictaluri, then fed Feed Medicated with Aquaflor at 10 mg FFC/kg of Fish Bodyweight for 10 days. The Feeding Regimens were Initiated 24 Hours After Exposure to E. Ictaluri.
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Efficacy of Aquaflor Demonstrated by Reduced Mortality in Channel Catfish Challenged with F. Columnare, then fed Feed Medicated with Aquaflor at 10 mg FFC/kg of Fish Bodyweight for 10 Days. The FeedingRegimens were Initiated 24 Hours After Exposure to F. Columnare.
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In 2009, high mortality in market-size catfish (~2 lbs or 0.907 g) associated with A. hydrophila occurred on several farms in Alabama, USA. Aquaflor was used to contain the outbreak. There were no untreated controls in these studies for both animal welfare and economic reasons. Nonetheless, comparison of mortality before...