Pulmonary and tracheal concentrations of Lincomycin, Tylosin, acetyl isovaleryl tylosin and tiamulin given as feed additives in swine

Grower pigs, approximately 4 months old, were fed adlibitum with feed containing 110 & 44 ppm lincomycin, 110 ppm tylosin, 110 ppm acetyl isovaleryl tylosin (AIV), or 110 ppm tiamulin. At 110 ppm, lincomycin, with a lung concentration of 0.85 mcg/g, showed better lung levels than the other antibiotics: tylosin (0.05 mcg/g), AIV (0.14 mcg/g), and tiamulin (0.63 mcg/g). This lincomycin concentration in swine lung is about 10 times higher than its MIC against Mycoplasma hyopneumoniae (M. hyo), while that of tylosin is below its MIC against the same organism. Even at 44 ppm, lincomycin was found at a higher concentration than its MIC against M. hyo. All antibiotics tested showed poor transfer to the swine trachea. The results suggest that oral administration of lincomycin as a feed additive can be a very efficient method for controlling mycoplasmal pneumonia in swine.