Fabrication, Properties And Application Of The Antibiotic Florfenicol Pills In Fishery

Recently the incidence of diseases induced from bacteria or/and otherinfirmities and culture water pollution in fishery increases obviously due toindustrial and agricultural waste, high stocking density, inappropriate cultureconditions and application of muddled fish baits, which resulting in decreasedquality and mortality rate of the cultivates. In Pseudosciaena crocea culture, therestill existed problems like drug abusiveness, poor efficacy, nonquantativelymedicine feeding and improper feeding style etc., which raised high morbidity andmortality rates of cultivated Pseudosciaena crocea obviously.Some kinds of traditional medicine such as pyrethroid, copper sulfate,malachite green, furans etc. were used in aquaculture with the styles of directthrowing in water or/and feeding together with the food. The fed medicine willabsolutely pollute the aquatic system because the medicine is free in water. On theother hand, the medicine dosage cannot be calculated exactly and can not beswallowed completely by fish, so that the pesticide effectiveness is usually quite low.Therefore, it is necessary to discover a novel feeding style or novel drug pill to solvethese problems.In this work, several biodegradable materials such as polylactic acid, starch,chitosan and gelatin were applied to be substrates to produce granulated pills inwhich antibiotic florfenicol was encapsulated. The internal structure of the carrierand the completed pills were observed individually under scanning electronmicroscope. The microscopic structures of both carrier and pill were quite uniformin pore size and pore distribution with good interconnectivity between pores, whichis favorable for the drug’s circulation and release. The pills’ chemistry was verifiedby infrared scanning. There was no chemical bonding between florfenicol and carrier materials, which will be useful for florfenicol to keep its biofunction whenthe pills were used in fishery.The release property of the pill was determined in UV-visiblespectrophotometer and high-performance liquid chromatography (HPLC) after itwas immersed in seawater for some time. The result showed that the drug releasedin seawater relatively slow and the amount is very few, which is believed to beuseful for the aquaculture system to prevent drug’s pollution.The in vitro antibacterial experiment showed that the antimicrobial propertiesof the pills were much obvious after the antibiotic florfenicol was encapsulated intothe carriers while carriers themselves didn’t exhibit any antimicrobial activity.The in vivo toxicity, pharmacokinetics and drug residues as a function of timewere tested in fishery with Pseudosciaena crocea as the test fish. The samples offish’s blood, liver and muscle were obtained and evaluated after they were fed incage culture for some time. The results show that the carriers themselves were safefor Pseudosciaena crocea, no obvious harm was found. After fed for5-7days, littleresidue of drug florfenicol was tested in blood, liver and muscle tissue ofPseudosciaena crocea. The pharmacokinetics was in line with a two compartmentopen model.In summary, pills consisting of carriers like starch, chitosan and gelatin (ratio is4:3:1) and drug florfenicol (20%) were a good system for the cage culture ofPseudosciaena crocea in fishery with little toxicity, antibacterial efficiency,biodegrability, good release properties and environmental friendship. Thepharmacokinetics of florfenicol in fish blood, liver and muscle tissue are in line witha two compartment open model in the metabolic processes. This system will be apractical and promising medicine feeding for cage culture fishery.