tylvalosin and Swine-Diseases

The effect of an oral treatment with the tartrate salt of tylvalosin on the development of proliferative enteropathy in 60 experimentally challenged pigs was studied. Thirty of the pigs were fed a diet medicated with 50 ppm tylvalosin and 30 were fed the unmedicated diet. The treated animals started to receive the medicated feed the day before they were inoculated, and continued to receive it for 14 days. The pigs' bodyweight, feed consumption and clinical signs were evaluated, and they were examined postmortem 20 days after inoculation, and samples of ileum were collected for immunohistochemistry (IHC) for Lawsonia intracellularis. Clinical signs of the disease were more evident in the untreated group than in the treated group. The average daily weight gain, average daily feed consumption and feed conversion efficiency were better in the treated group. The combined length of intestine with lesions was 2847 cm in the untreated group and 183 cm in the treated group. The tylvalosin treatment significantly reduced the level of L intracellularis infection; almost half of the treated pigs were IHC-negative compared with 3.3 per cent of the untreated pigs.

Topics: Animal Feed; Animals; Anti-Bacterial Agents; Desulfovibrionaceae Infections; Ileitis; Swine; Swine Diseases; Time Factors; Tylosin

The effect of a water-soluble formulation of tylvalosin (Aivlosin® 625 mg/g granules) on disease caused by porcine reproductive and respiratory syndrome virus (PRRSV) and Mycoplasma hyopneumoniae (Mhyop) was investigated in two animal studies. In a PRRSV challenge model in pregnant sows (n = 18), six sows received water medicated at target dose of 5 mg tylvalosin/kg body weight/day from 3 days prior to challenge until the end of gestation. Six sows were left untreated, with a third group remaining untreated and unchallenged. Sows were challenged with PRRSV-2 at approximately 85 days of gestation. Cytokines, viremia, viral shedding, sow reproductive parameters and piglet performance to weaning were evaluated. In a dual infection study (n = 16), piglets were challenged with Mhyop on days 0, 1 and 2, and with PRRSV-1 on day 14 and euthanized on day 24. From day 10 to 20, eight piglets received water medicated at target dose of 20 mg tylvalosin/kg body weight/day and eight piglets were left untreated. Cytokines, viremia, bacteriology and lung lesions were evaluated.. Overall, tylvalosin reduced both local and systemic proinflammatory cytokines after challenge with respiratory pathogens in sows and in piglets. Tylvalosin was effective in reducing Mhyop recovery from the lungs and may reduce virus shedding in piglets following transplacental PRRSV infection in sows.

Topics: Animals; Body Weight; Cytokines; Female; Granulocyte-Macrophage Colony-Stimulating Factor; Interleukin-10; Interleukin-12; Interleukin-8; Mycoplasma hyopneumoniae; Porcine Reproductive and Respiratory Syndrome; Porcine respiratory and reproductive syndrome virus; Pregnancy; Swine; Swine Diseases; Tumor Necrosis Factor-alpha; Viremia

Mycoplasma hyopneumoniae is involved in the porcine enzootic pneumonia and respiratory disease complex; therefore, the search for new treatment options that contribute to the control of this organism is relevant. The minimal inhibitory concentrations (MICs) and minimal bactericidal concentrations of tylvalosin and 19 other antimicrobial agents against 20 Spanish field isolates of M. hyopneumoniae were determined using the broth microdilution method, with the type strain (J) as a control strain. Tylvalosin had MIC50 and MIC90 values of 0.016 and 0.06 µg/ml, respectively, and was the second-most effective of the assayed antibiotics, after valnemulin. Tiamulin, tylosin and lincomycin were also among the antibiotics with the lowest MIC50 and MIC90 values against the 20 field isolates (0.06-0.25 µg/ml). However, resistance to tylosin and spiramycin, which like tylvalosin, are 16-membered macrolides, was observed. The MIC50 and MIC90 values for ciprofloxacin and enrofloxacin ranged from 0.125 to 1 µg/ml; the corresponding values ranged from 2 to 4 µg/ml for oxytetracyline, which was the most active tetracycline. Furthermore, tylvalosin and valnemulin exhibited the highest bactericidal activities. In conclusion, the macrolide tylvalosin and the pleuromutilin valnemulin exhibited the highest in vitro antimicrobial activities against M. hyopneumoniae field isolates in comparison with the other tested antibiotics.

Topics: Animals; Anti-Infective Agents; Bacterial Load; In Vitro Techniques; Microbial Sensitivity Tests; Mycoplasma hyopneumoniae; Spain; Swine; Swine Diseases; Tylosin

Ear necrosis and shoulder ulcers in pigs are animal welfare problems and ethical issues that can cause economic losses for producers. Spirochetes have been observed microscopically in scrapings from pig ulcers since the early 1900s, but have until recently not been cultured and therefore not characterized. In this study, 12 Treponema spp. isolates were acquired from porcine ear necrosis, shoulder ulcers and gingiva. DNA analysis of the 16S rRNA-tRNA(Ile) intergenic spacer region (ISR2) or the 16S rRNA gene revealed relatedness to oral treponemes found in dogs and humans. All isolates except one aligned into two clusters, Treponema pedis and Treponema sp. OMZ 840-like. The 16S rRNA gene of the remaining isolate shared 99% nucleotide identity with Treponema parvum. Genetic fingerprinting of the isolates was performed through random amplification of polymorphic DNA (RAPD). In addition, the isolates were characterized by biochemical tests, including api(®)ZYM, tryptophanase and hippuricase activity, and by testing the antimicrobial susceptibility to tiamulin, valnemulin, tylosin, tylvalosin, lincomycin and doxycycline using broth dilution. All isolates except two showed unique RAPD fingerprints, whereas metabolic activity tests could not differentiate between the isolates. The MICs of all antimicrobial agents tested were low.

Topics: Animals; Anti-Bacterial Agents; Base Sequence; Doxycycline; Ear; Lincomycin; Microbial Sensitivity Tests; Molecular Sequence Data; Necrosis; Phylogeny; Random Amplified Polymorphic DNA Technique; Shoulder; Swine; Swine Diseases; Treponema; Treponemal Infections; Tylosin; Ulcer

The 21 field isolates of Treponema hyodysenteriae which were tested were sensitive to 3-acetyl-4''-isovaleryl tylosin (AIV); the minimal inhibitory concentration was 0.25 to 16 micrograms/ml. 3-Acetyl-4''-isovaleryl tylosin administered prophylactically to pigs at concentrations of 5 to 100 mg/kg of feed and tylosin at 110 mg/kg of feed for 28 or 31 days prevented swine dysentery induced by tylosin-sensitive T hyodysenteriae strain SQ2; 15 nonmedicated, inoculated control pigs had bloody diarrhea, and 9 pigs died. In 2 additional trials, AIV administered prophylactically for 28 days at 55 or 110 mg/kg of feed prevented swine dysentery induced by tylosin-insensitive T hyodysenteriae strain B204. All of the inoculated principal pigs medicated with AIV at 55 or 110 mg/kg of feed or carbadox at 55 mg/kg of feed and the noninoculated sentinel pigs for each group had solid feces throughout the 56-day trial. In the nonmedicated, inoculated control groups, bloody diarrhea began at 4 to 5 days after inoculation was done, and 9 of 10 principal pigs and 6 of 9 sentinel pigs had dysentery; 2 pigs died. In the groups medicated with AIV at 27.5 or 5.5 mg/kg of feed, all 5 principal pigs and 3 or 4 sentinel pigs in each group had dysentery; 3 or 4 pigs in each group died. In the group medicated with tylosin at 110 mg/kg of feed, 7 of 10 principal pigs and all 9 sentinel pigs had dysentery; 1 pig died.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Carbadox; Dysentery; Leucomycins; Microbial Sensitivity Tests; Swine; Swine Diseases; Treponema; Treponemal Infections; Tylosin