In certain countries the ionophore antibiotic salinomycin is used as a growth promoter in pig diets at levels of 15 - 60ppm to enhance growth rate and feed conversion efficiency. However, in the EU the use of salinomycin as an in-feed growth promoter for pigs will be banned from January 1st 2006 in accordance with EU policy to ban all in-feed antimicrobial growth promoters.
A dose-related toxic interaction in pigs between salinomycin and Tiamutin has been described by Miller and others. [?] Within 24 hours of the concurrent administration of salinomycin and therapeutic levels of Tiamutin, severe clinical signs of primary ionophore toxicity occur in pigs i.e. muscle tremors, inappetence, hind limb ataxia or incoordination and death.
A combined intake level of no more than 6mg (total of both active ingredients)/kg bodyweight has been defined as a safe and acceptable level, e.g. a combination in-feed of 40ppm tiamulin (which provides an intake level of approximately 2.0mg active ingredient/kg bwt) plus 60ppm salinomycin (which provides an intake level of approximately 3.0mg active ingredient/kg bwt). This combination would therefore be acceptable since the combined intake level does not exceed 6.0mg/kg bwt (2.0mg/kg + 3.0mg/kg) [?].
No clinical abnormalities occur in pigs when prophylactic/control levels of Tiamutin premix (30 -40ppm tiamulin) are administered to pigs concurrently with diets containing approved levels of salinomycin [?].
| SAFETY PERIOD |
| It is essential that a period of at least four days should elapse before pigs receiving a therapeutic level of Tiamutin should be exposed to salinomycin containing feed [?]. |
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