In accordance with the maximum residue limit of 100 micrograms kg-1 established by EU legislation, a simple and sensitive high-performance liquid chromatographic (HPLC) method was developed for the measurement of tylosin residues in pig tissues (fat, kidney, liver and muscle). Tylosin, a macrolide antibiotic, is extracted with water-methanol and cleaned-up by solid-phase extraction (SPE) on cat...

Studies on the susceptibility of pathogenic Nocardia to macrolide antibiotics, chalcomycin and tylosin, showed that most of the Nocardia species examined were highly resistant to both antibiotics, although N. nova was moderately susceptible. N. asteroides IFM 0339 converted these macrolides into inactive metabolites by glycosylation at 2'-OH or glycosylation and reduction of the 20-formyl group...

The efficacy of the pleuromutilin derivative 81.723 hfu was tested in chicks and turkey poults by experimentally infecting them with Mycoplasma gallisepticum. The data were treated to obtain the mean effective doses, and these were compared to those obtained with tylosin tartrate. The compounds were administered either by ingluvial catheter or via the drinking water. Therapy was started on the ...

The behavior of three antibiotics (bacitracin, chlortetracycline, and tylosin) and two classes of antibiotic resistance genes (ARGs), tet and erm, were monitored in swine manure slurry under anaerobic conditions. First-order decay rates were determined for each antibiotic with half-lives ranging from 1 day (chlortetracycline) to 10 days (tylosin). ARGs were monitored in the swine manure slurry,...

Continuous now cultures of feral (culture FC) and domesticated (culture RPCF) p1g gut micronora were established in steady state. Cultures, in duplicate, were continuously infused subtherapeut1c (2S lJg/ml) levels of tylosm and sampled at mtervals to assess effects on tota l culturable anaerobes, Bacteroides spp. and Enterococcus spp. v1a plating on seria l 1 0-fold dilutions to anaerobiC Bruce...

A total of 3,632 crossbred steers were used in 3 separate randomized complete-block designed finishing experiments. Data from Exp. 1 were analyzed separately whereas data were combined for Exp. 2 and 3, based on corn processing method used [Exp.1 = equal combination of dry-rolled and high-moisture (DRC:HMC); Exp. 2 and 3 = steam-flaked (SFC)]. Steers were fed 1 of 5 treatments to evaluate the e...

Land application of manure containing antimicrobials results in the dispersion of the antimicrobials in agro-ecosystems. Dissipation of excreted antimicrobials in seasonally frozen agricultural soils has not been fully characterized under field conditions. This study investigated the field dissipation kinetics of chlortetracycline, sulfamethazine, and tylosin over a 10-mo period after fall appl...

The effect of tylosin on erythromycin-resistant enterococci was examined on three farms; farm A used tylosin for growth promotion, farm B used tylosin for treatment of disease, and farm C did not use tylosin for either growth promotion or disease treatment. A total of 1,187 enterococci were isolated from gestation, farrowing, suckling, nursery, and finishing swine from the farms. From a subset ...

Two commercially available enzyme-linked immunosorbent assay (ELISA) kits that are commonly used for tylosin or tetracycline residues in meat and milk were adapted for ultratrace analysis of these antibiotics in surface and ground waters. These two antibiotics are commonly fed to swine, turkeys, and cattle at subtherapeutic doses for growth promotion purposes. Both ELISA techniques were found t...

Abstract This study evaluated different strategies of forage inclusion for finishing beef cattle and their impact on performance, carcass quality, liver abscesses. Steers (n=360, 400±29 kg) were blocked by weight randomly assigned to one four treatments (15 steers/pen, 6 pens/treatment) in a complete randomized experiment. Treatments were: 1) positive control (+CON) fed diet (7.5% DM basis) wit...