Medicated Fish Feed Research Articles

Efeito do revestimento com etilcelulose de ração medicada contendo albendazol sobre a eficácia do tratamento da acantocefalose em tambaqui (Colossoma macropomum) naturalmente parasitado

ABSTRACT Coating medicated fish feed with a polymer minimizes the chances of drug leaching into the water. Tambaqui (Colossoma macropomum) is an economically important Amazonian fish frequently parasitized by the acanthocephalan Neoechinorhynchus buttnerae. In this study, we compared the effect of ethylcellulose (EC 0.75%) coating of feed medicated with the antihelminthic albendazole (ABZ 10 mg kg bw-1) and uncoated feed on treatment efficacy and bioaccumulation of ABZ in naturally parasitized tambaqui during 35 days. Treatment efficacy was 34% and 66% in fish fed uncoated and coated feed, respectively, but did not vary significantly among treatments. Total ABZ residue reached concentrations from 122.0 to 151.7 ng g-1, and did not vary significantly among treatments. The biomagnification factor was low, ranging from 0.0003 to 0.0004. EC coating did not significantly affect the efficacy of ABZ treatment and did not interfere with ABZ bioaccumulation in the edible tissue of tambaqui.

Evaluation of oxytetracycline leaching from pregelatinized starch-coated medicated fish feed.

The rapid growth and intensification of aquaculture industries have led to an increased use of antibiotics. Consequently, growing concerns have mounted over the environmental contamination of these drugs from medicated feeds and the risk that this poses for antimicrobial resistance. To circumvent environmental leaching, farmers topcoat medicated feeds with oil; however, this only partially addresses the issue. This study investigated the potential of food-grade pregelatinized corn starch (PGS) as a second top-coating agent to reduce oxytetracycline (OTC) leaching from the hand-mixed medicated feed. We immersed top-coated medicated feeds for different periods of time and measured the concentration of OTC in the water to determine leaching. We found a significantly lower level of OTC in water samples collected from the PGS-coated medicated feed compared to the non-PGS-coated medicated feed, with concentrations of OTC approximately 4 and 2.6 times the latter after 5 min and 2 h of water immersion, respectively. We also fed PGS-coated antibiotic feed to jade perch to determine if fish accepted the top-coating and whether they absorbed the OTC. Results from a feeding trial suggested no difference in palatability between PGS and non-PGS-coated medicated feed. We also found that muscle tissue from fish fed with the aforementioned diets had similar levels of OTC concentrations, suggesting that PGS coating does not alter the gastrointestinal absorption of this medication. From our experiment, we conclude that PGS is potentially a new top-coating agent to reduce leaching in hand-mixed OTC medicated feed.

Effects of an aquaculture pesticide (diflubenzuron) on non-target shrimp populations: Extrapolation from laboratory experiments to the risk of population decline

Marine aquaculture production has lately experienced high economic growth, but also concerns related to production and environmental contamination. For the Atlantic salmon aquaculture industry, the ectoparasitic crustacean salmon louse (Lepeophtheirus salmonis) has become a major problem. A common method to control populations of salmon lice within farm cages is treatment by various pharmaceuticals. One of the pesticides used in medicated feed for salmon is diflubenzuron (DFB), which acts as a chitin synthesis inhibitor and thereby interferes with the moulting stages during the development of this crustacean. However, DFB from fish feed may also affect non-target crustaceans such as the northern shrimp (Pandalus borealis), which is an economically and ecologically important species. Nevertheless, the actual risk posed by this chemical to shrimp populations in nature is largely unknown. Laboratory experiments have demonstrated that both larval and adult shrimp exposed to DFB through medicated fish feed have reduced survival compared to control. Moreover, the effects of DFB exposure are more severe under conditions of higher temperature and reduced pH (ocean acidification), which can be expected in a future environment. The aim of this study is to make the individual-level information from laboratory studies more relevant for risk assessment at the population level. We have developed a density-dependent age-structured population model representing a northern shrimp population located in a hypothetical Norwegian fjord containing a fish farm, under both ambient and future environments. Our model is based on thorough documentation of shrimp biology and toxicological effects from the laboratory experiments. Nevertheless, extrapolating the reported individual-level effects of DFB to the population level poses several challenges. Relevant information on shrimp populations in Norwegian fjords is sparse (such as abundances, survival and reproductive rates, and density-dependent processes). The degree of exposure to DFB at different distances from aquaculture farms is also uncertain. We have therefore developed a set of model scenarios representing different DFB application schemes and different degrees of exposure for the shrimp populations. The model predicts effects of DFB exposure on population-level endpoints such as long-term abundance, age structure and the probability of population decline below threshold abundances. These model predictions demonstrate how the risk of DFB to shrimp populations can be enhanced by factors such as the timing (season) of DFB applications, the percentage of the population affected, future environmental conditions and environmental stochasticity.

Evaluation of the leaching of florfenicol from coated medicated fish feed into water

Florfenicol is one of the most-used antimicrobial agents in global fish farming. Nevertheless, in most countries, its use is not conducted in accordance with good practices. The aim of this work was to evaluate the leaching of florfenicol from coated fish feed into the water. Analytical methods were developed and validated for the quantitation of florfenicol in medicated feed and water by UHPLC-MS/MS. Florfenicol residues in the water were quantified after 5- and 15-min exposures of the medicated feed in the water at 22 and 28 °C and at pH 4.5 and 8.0. The influence of pellet size and three coating agents (vegetable oil, carboxymethylcellulose, and low-methoxylated pectin) on the leaching of the drug was also assessed. Pellet size, coating agent, water temperature, and time of exposure significantly (p < 0.05) affected florfenicol leaching, while water pH did not interfere with the leaching. Coating with vegetable oil was the most efficient method to reduce florfenicol leaching, while coating with carboxymethylcellulose presented the highest leaching (approximately 60% after 15 min at 28 °C). Thus, the coating agent has a significant effect on the florfenicol leaching rate and, consequently, on the necessary dose of the drug to be administered. Moreover, it is worth mentioning that higher florfenicol leaching will pose a greater risk to environmental health, specifically in terms of the development of bacteria resistant to florfenicol. Additional studies are needed with other polymers and veterinary drugs used in medicated feed for fish farming.

Analysis of enterotoxigenic Bacillus cereus strains from dried foods using whole genome sequencing, multi-locus sequence analysis and toxin gene prevalence and distribution using endpoint PCR analysis

Bacillus cereus strains were isolated from dried foods, which included international brands of spices from South East Asia, Mexico and India purchased from several retail stores, samples of powdered infant formula (PIF), medicated fish feed and dietary supplements. The genetic diversity of 64 strains from spices and PIF was determined using a multiplex endpoint PCR assay designed to identify hemolysin BL, nonhemolytic enterotoxin, cytotoxin K, and enterotoxin FM toxin genes. Thirteen different B. cereus toxigenic gene patterns or profiles were identified among the strains. Randomly selected B. cereus strains were sequenced and compared with reference Genomic Groups from National Center Biotechnology Information using bioinformatics tools. A comprehensive multi-loci sequence analysis (MLSA) was designed using alleles from 25 known MLST genes specifically tailored for use with whole genome assemblies. A cohort of representative genomes of strains from a few FDA regulated commodities like dry foods and medicated fish feed was used to demonstrate the utility of the 25-MLSA approach for rapid clustering and identification of Genome Groups. The analysis clustered the strains from medicated fish feed, dry foods, and dietary supplements into phylogenetically-related groups. 25-MLSA also pointed to a greater diversity of B. cereus strains from foods and feed than previously recognized. Our integrated approach of toxin gene PCR, and to our knowledge, whole genome sequencing (WGS) based sequence analysis, may be the first of its kind that demonstrates enterotoxigenic potential and genomic diversity in parallel.

HPLC Profile of Medicinal Plant Extracts and its Application in Aquaculture

High Performance Liquid Chromatography technique based screening of medicinal proteins as fish feed were prepared from the selected medicinal plants such as Leucas aspera, Achyranthes splendens, and Swertia chirayita. The present study aims at arrival of quality profile of protein in the medicinal plants which are main ingredients in the fish feed. Antibacterial activity of the medicinal plant extracts was assessed and based on that the self-formulated fish feed was formulated. The medicinal feed surpassed the quality of commercial fish feed by having higher protein and fibre along with medicinal properties. In the present study fish pathogens were isolated from the infected fishes and cultured on a suitable medium. Control of pathogens by 80%, 92%and 87% Leucas aspera, Achyranthes splendens and Swertia chirayita respectively revealed the efficiency of medicinal plants than the control. This study enabled that the medicated fish feed curtails the high cost of fish diet and can be used as potential high quality alternative source in the aquaculture industry

Simultaneous Determination of Sulphadiazine Sodium and Trimethoprim in Medicated Fish Feed, Fish Tissues and in Their Veterinary Pharmaceutical Formulation by Thin-Layer Chromatography-Densitometry

A specific, precise, and accurate thin-layer chromatographic method for the simultaneous estimation of sulphadiazine sodium (SDZ) and trimethoprim (TMP) in medicated fish feed and in fish tissues was developed and validated. This method is based on simple liquid extraction technique and employing thin-layer chromatography (TLC) as a cleanup step. In order to optimize the extraction procedure from fish tissues, several mobile phase systems and extracting solvents were tried. The method employed TLC aluminum plates precoated with silica gel 60 F254 as the stationary phase and chloroform-toluene-ethanol-glacial acetic acid (4.5:4.5:1.0:1.0 by volume) mixture as the developing solvent. This system was found to give compact and dense spots for both sulphadiazine sodium (RF value of 0.48) and trimethoprim (RF value of 0.16) without interference from either medicated fish feed or fish tissues coextractives. Densitometric analysis of both drugs was carried out in the reflectance-absorbance mode at 270 nm for SDZ ...

Determination of Florfenicol in Fish Feed by Liquid Chromatography

A simple, accurate, and reproducible assay was developed for the determination of Florfenicol in medicated fish feed. Florfenicol was extracted from ground feed into an acetonitrile-water mixture by shaking and sonication. A portion of the centrifuged extract was passed through an Envi-Carb solid-phase extraction cartridge, through which Florfenicol eluted unretained. The collected eluant was diluted to adjust for analyte concentration, and injected into a reversed-phase liquid chromatography system. Samples were quantitated by external standard analysis versus multilevel calibration solutions. The procedure is suitable for the quantitation of samples medicated with 0.2-4 g/kg Florfenicol. Accuracy was evaluated by 2 analysts, who determined recovery of Florfenicol from feeds fortified over a range of 0.1-6.0 g/kg. The average recovery was 100.5% (relative standard deviation, 1.2%). The linearity, accuracy, precision, reproducibility (interday and analyst), and selectivity of the method are presented. The detection and quantitation limits were determined to be 0.2 and 1.0 mg/kg, respectively.

Determination of Emamectin Benzoate in Medicated Fish Feed: A Multisite Study

A new method was developed for the quantitation of emamectin benzoate in medicated fish feed at levels between 1 and 30 ppm. The new procedure, based on a previously reported assay, consists of a wet methanolic extraction of ground feed, followed by solid-phase extraction and injection onto a gradient liquid chromatographic system. A multisite study involving 3 laboratories (the developing laboratory and 2 independent laboratories) was performed to evaluate precision, recovery, linearity, and sensitivity. Mean recove;ries for triplicate analyses at 3 levels, performed by 2 analysts per laboratory, were between 89 and 97%, with coefficients of variation ranging from 1.6 to 8.6%. Coefficients of determination (r2) obtained from the plotted data were > or =0.993. The precision of the method, determined from 6 replicate preparations from the same batch of medicated feed assayed in 3 separate trials per laboratory, was between 0.6 and 5.8%. The quantitation limit was established at 0.5 ppm. Specificity and robustness studies were performed by the developing laboratory.

Comparison Study of Two Procedures for the Determination of Emamectin Benzoate in Medicated Fish Feed

A new method has been developed for the determination of emamectin benzoate in fish feed. The method uses a wet extraction, cleanup by solid-phase extraction, and quantitation and separation by liquid chromatography (LC). In this paper, we compare the performance of this method with that of a previously reported LC assay for the determination of emamectin benzoate in fish feed. Although similar to the previous method, the new procedure uses a different sample pretreatment, wet extraction, and quantitation method. The performance of the new method was compared with that of the previously reported method by analyses of 22 medicated feed samples from various commercial sources. A comparison of the results presented here reveals slightly lower assay values obtained with the new method. Although a paired sample t-test indicates the difference in results is significant, this difference is within the method precision of either procedure.

Determination of Emamectin Benzoate in Medicated Fish Feed

A method was developed to quantitate emamectin benzoate in fish feed at levels between 5 and 15 ppm. The active ingredient is extracted from 20 g medicated feed into aqueous-methanolic solvent by overnight shaking. A solid-phase extraction procedure using a 2 g C18 cartridge is then used to concentrate the active residue and remove interfering matrix components. The extracted drug and internal standard are eluted from the cartridge, evaporated to dryness, and reconstituted in methanol. A control feed sample and fortified control working standard are simultaneously prepared. Remaining interferences and sample analysis are further separated on a gradient liquid chromatographic system. Recovery of emamectin benzoate from fortified feeds ranged from 97 to 100%, with a coefficient of variation (CV) of 1.2%. Determination of emamectin benzoate in medicated feeds resulted in CVs ranging from 2.3 to 4.2% and recoveries of 88 to 98% of label claim.

Antibacterial resistant bacteria in surficial sediments near salmon net-cage farms in Puget Sound, Washington

Antibacterials are used in medicated fish feed at fish farms located in Puget Sound, Washington. These compounds include oxytetracycline (OTC), amoxycillin, and Romet ® 30 (a drug composed of sulfadimethioxine and ormetoprim). In this study we collected surficial sediment samples at three different commercial salmon net-cage farms during the summer and early fall of 1992. The three different farms varied in their use of antibacterials. Before beginning our field investigation we developed a modification of Mueller Hinton Agar to enumerate antibacterial-resistant bacteria. A synthetic seawater was added at 70% concentration to Mueller Hinton Agar. Because the divalent cations present in seawater chelate OTC, the concentration of this antibacterial was increased in the seawater medium relative to concentrations typically used in clinical microbiology laboratories. We enumerated the total number of cultivable bacteria, and bacteria resistant to oxytetracycline, amoxycillin, or Romet ® 30 by plating aliquots of sediment samples onto the marine Mueller Hinton Agar. The highest numbers of bacteria (10 6 to 10 8 colony forming units g −1) were generally found nearest the net-cages with densities declining about an order-of-magnitude further away from the cages. Farm A, which used the greatest amount of antibacterials of the three farms, had the highest percentages of antibacterial-resistant bacteria in the sediments. At this Farm resistance to Romet ® 30 and OTC tended to parallel each other, suggesting either a common resistance mechanism or linkage of the genes responsible for the resistances. Farm C used the least amount of antibacterials and this was reflected in that this farm also had the lowest percentage of sedimentary bacteria that were resistant to the antibacterials. Although the total number of bacteria at Farm C was in a similar range as found at Farms A and B, the percentages of antibacterial resistant bacteria were 5% or less for most of the samples. Our results suggest that a background of less than 5% of the cultivable bacteria in marine sediments is resistant to OTC, Romet ® 30, or amoxycillin.

Bioavailability of flumequine after oral administration to Atlantic salmon ( Salmo salar L.)

The bioavailability of flumequine was investigated in Atlantic salmon ( Salmo salar L.) in seawater at 6–8 °C. Four types of commercially available medicated fish feed containing flumequine (5 g kg −1) were administered to different groups of salmons (dose: 25 mg kg −1 body weight). The drug was also given as an intravascular bolus injection (dose: 10 mg kg −1 b.w.) and in form of a suspension in water, fish oil or corn oil (dose: 25 mg kg −1 b.w.). Elimination half-lives of 30–40 h were found. The bioavailability of all the tested products was around 40%. Neither the absorption rate, the absorption pattern, nor the presence of feed seemed to have any influence on the bioavailability. The in vitro flumequine release from the medicated feed pellets was tested using a flow-through apparatus as described in the European Pharmacopoeia. A clear difference in dissolution profile among the four products was seen.

Determination of Praziquantel in Medicated Fish Feed and Sediment by HPLC

Abstract A simple method for the determination of praziquantel (2-cyclohexylcarbonyl-4-oxo-1,2,3,6,7,llb-hexahydro-4H-pyrazino [2,1-a]isoquinoline-4-one) in medicated fish feed, and sediment by HPLC, is presented. The calibration curves were linear in the investigated areas, 0.5 – 5 mg/g praziquantel for fish feed and 30 – 500 ng/g for sediment, and the recovery rates were 99 to 100%, respectively.

Simultaneous extraction and determination of sulfadiazine and trimethoprim in medicated fish feed by high-performance liquid chromatography

A simple and rapid method for the simultaneous extraction and determination of sulfadiazine and trimethoprim in medicated fish feed by HPLC using sulfadimidine as internal standard is presented. The calibration curves were linear in the investigated areas, 1.25–10 mg/g of sulfadiazine and 0.25–2 mg/g trimethoprim. The recovery of sulfadiazine was 96–99%, and the recovery of trimethoprim 100–105%.

High-performance liquid chromatographic determination of several quinolone antibacterials in medicated fish feed

High-performance liquid chromatographic determination of several quinolone antibacterials in medicated fish feed