[Toxicity of the combination of salinomycin and tiamulin in swine].

The toxicity of the combination of salinomycin (sal.) and tiamulin (tia.) was investigated in dependence upon dosage and feeding method. In addition the efficacy of a safe dose for prophylactic treatment of dysentery was controlled. Following feed medications were tested for toxic effects in pigs: a) 3 mg sal. + 5 mg tia./kg BW, b) 3 mg sal. + 3 mg tia./kg BW, c) 3 mg sal. + 1 mg tia./kg BW, d) 3 mg sal./kg BW, e) 10 mg tia./kg BW, f) 30 mg tia./kg BW. The daily dose was given for 2 weeks by restricted feeding (twice a day) either as bolus or mixed in the whole ration or by feeding ad libitum. Animals were controlled for clinical symptoms and activities of creatine phosphokinase (CK) and aspartate aminotransferase (ASAT) were evaluated daily. Main clinical signs of poisoning were loss of appetite and locomotor disturbances and could be noticed for dosages of 8, 6 and 4 mg sal. + tia./kg BW. Activities of CK and ASAT were increased dose-related, the feeding method also had an influence on the degree of intoxication. Some animals showed locomotor disturbances without any corresponding changes of CK and ASAT levels. Single pigs remaining without any symptoms even at high dosage pointed to differences in individual susceptibility. Toxicity was not found to be age dependent. Feed medication with 60 ppm sal. + 20 ppm tia. (feeding ad libitum) did not result in any signs of toxicity, however, the transmission of Serpulina hyodysenteriae from infected pigs to healthy, treated control animals could not be inhibited efficiently. Therefore the simultaneous application of salinomycin and tiamulin should be avoided generally, because the risk of intoxication is high and subtherapeutical dosage has an insufficient effectiveness against Serpulina hyodysenteriae.