A Green HPLC Approach to Florfenicol Analysis in Pig Urine.

Florfenicol (FF) is a broad-spectrum antibiotic used to treat gastrointestinal and respiratory infections in domestic animals. Considering FF's rapid elimination via urine after drug treatment, its use increases concerns about environmental contamination. The objective of the study was to establish a sustainable chromatographic method for simple analysis of FF in pig urine to investigate the urinary excretion of FF after a single intramuscular administration of 20 mg FF/kg body weight. The urine sample was prepared using a centrifuge and regenerated cellulose filter, and the diluted sample was analyzed. The method was validated in terms of linearity, the limit of detection (0.005 µg/mL) and quantitation (0.016 µg/mL), repeatability and matrix effect (%RSD ranged up to 2.5), accuracy (varied between 98% and 102%), and stability. The concentration-time profile of pig urine samples collected within 48 h post-drug administration showed that 63% of FF's dose was excreted. The developed method and previously published methods used to qualify FF in the urine of animal origin were evaluated by the National Environmental Method Index (NEMI), Green Analytical Procedure Index (GAPI) and Analytical GREENness Metric Approach (AGREE). The greenness profiles of published methods revealed problems with high solvents and energy consumption, while the established method was shown to be more environmentally friendly.

Effects of immunostimulators of microbial origin on T cells of pigs vaccinated with attenuated vaccine against Aujeszky's disease.

Aujeszky's disease (AD) is a viral infectious disease caused by Suid herpesvirus 1 (SuHV-1). Vaccination and eradication of AD in domestic pigs is possible using marker vaccines with attenuated or inactivated SuHV-1, or subunit vaccines. However, vaccines with attenuated SuHV-1 have shown to be more potent in inducing strong cell-mediated immune response. The studies have shown that Parapoxvirus ovis, as well as Propionibacterium granulosum with lipopolysacharides (LPS) of Escherichia coli have pronounced immunomodulatory effects and that in combination with the vaccines can induce stronger humoral and cellular immune responses than use of vaccines alone. In our study distribution of peripheral blood T cell subpopulations was analysed after administration of vaccine alone (attenuated SuHV-1), immunostimulators (inactivated Parapoxvirus ovis or combination of an inactivated P. granulosum and detoxified LPS of E. coli) and combinations of vaccine with each immunostimulator to the 12-week old piglets. Throughout the study no significant changes were found in the proportions of γδ and most αß T cell subpopulations analysed. However, on the seventh day of the study combination of an inactivated P. granulosum and LPS of E. coli with vaccine induced transient but significant increase of the proportions of CD4+CD8α+ and CD4-CD8α+ αß T cells, that have been strongly associated with early protection of SuHV-1 infected pigs. Our findings indicate that combination of inactivated P. granulosum and detoxified E. coli LPS could be used for enhancement of a cellular immune response induced by vaccines against AD.

Accumulation of ractopamine residues in hair and ocular tissues of animals during and after treatment.

The aim of the present study was to assess the accumulation of ractopamine residues in the hair and ocular tissues of guinea pigs during repeated ractopamine administration and after treatment. The experiment was conducted in 38 guinea pigs (30 treated and eight controls). Treated animals were orally administered ractopamine hydrochloride in a dose of 3.5 mg/kg body mass per day using probes for seven consecutive days. Ractopamine concentration was determined in hair during the treatment (Days 1, 3 and 7) with ractopamine hydrochloride and in ocular tissues and hair on defined days after exposure (Days 1, 10, 20 and 30). Residues were present in hair in high concentrations as early as Day 3 (86.15 ± 87.71 ng/g) and Day 7 (85.25 ± 56.97 ng/g). After exposure, residues were found to persist, having depleted from 68.06 ± 30.54 ng/g on Day 1 to 8.01 ± 2.22 ng/g on Day 30, with a significantly higher concentration in hair in contrast to low residue levels in ocular tissues (1.20-0.34 ng/g). The results of the study pointed to high ractopamine accumulation, even in non-pigmented hair, suggesting hair to be used as a matrix in the control of ractopamine abuse in farm animals because of its many advantages over ocular tissues.