RESUMO
The therapeutic value of Florfenicol feed supplemented was evaluated in conventional pigs to eliminate consequences of chronic infection of Mycoplasma hyopneumoniae. The experimental animals were pigs with an average of 16 kg, after intratracheally inoculation with M. hyopneumoniae they were divided in two experimental groups: (a) the non-medicated; and (b) the feed supplemented group (20 g Florfenicol/ton of feed) during the ensuing 35 days. The average daily weight gain of the Florfenicol-treated pigs (0.33±0.14 kg/day) was significantly higher than that of the non-treated ones (0.21±0.10 kg/day). In medicated animals was still impaired relative to that of the uninfected ones control group (0.39±0.02 kg/day). The average percentage of pneumonic gross lesions extensions' of the pigs groups was: 13.99% for M. hyopneumoniae infected non-medicated group; 1.79% M. hyopneumoniae infected, Florfenicol-treated group and, 0.56% of the uninfected control group. M. hyopneumoniae; colonization was detected at these levels in 7 and 9 members of the respective infected groups. The extent of the pneumonic lesions and M. hyopneumoniae generally was greater in the non-medicated pigs. Therefore, oral administration of Florfenicol via feed ingestion seemed to be somewhat effective in ameliorating the clinical effects of M. hyopneumoniae infection of swine.
Assuntos
Antibacterianos/farmacologia , Suplementos Nutricionais , Mycoplasma hyopneumoniae/efeitos dos fármacos , Pneumonia Suína Micoplasmática/prevenção & controle , Doenças dos Suínos/prevenção & controle , Tianfenicol/análogos & derivados , Ração Animal , Animais , Imunidade Humoral/efeitos dos fármacos , Pulmão/patologia , México , Pneumonia Suína Micoplasmática/patologia , Suínos/crescimento & desenvolvimento , Suínos/microbiologia , Doenças dos Suínos/microbiologia , Tianfenicol/farmacologia , Aumento de Peso/efeitos dos fármacosRESUMO
The airborne transmission of Classical Swine Fever (CSF) virus to susceptible pigs, as well as the effect of vaccination with the CSF virus PAV-250 strain was investigated on this mode of transmission. Experiment I: four pigs were inoculated with the ALD CSFV strain (10(4.3) 50% TCID) by the intramuscular route, and at the onset of fever, they were introduced into an enclosed chamber. At the end of the experiment surviving pigs were sedated, anesthetized and euthanatized. Experiment II: four pigs were previously vaccinated with the CSF virus PAV-250 strain, and at 14 days post-vaccination they were challenged with the CSF virus ALD strain. In both experiments, four susceptible pigs were exposed to infectious aerosols by placing them in a chamber connected by a duct to the adjacent pen containing the infected animals and were kept there for 86 hs. In Experiment I, pigs exposed to contaminated air died as a result of infection with CSF virus on days 14, 21 and 28 post-inhalation. These four pigs seroconverted from day 12 post-inhalation. CSF virus was isolated from these animals, and the fluorescent antibody test on tonsils was positive. In Experiment II, a vaccinated pig exposed to contaminated air did not seroconvert, nor was CSF virus isolated from lymphoid tissues. However, mild fluorescence in tonsil sections from these pigs was observed. In conclusion, CSF virus was shown to be transmitted by air at a distance of 1 m to susceptible pigs. Vaccination with the PAV-250 CSF virus strain protected the pigs from clinical disease under the same conditions.