Cross-contamination of non-target feedingstuffs by semduramicin authorised for use as a feed additive
Semduramicin is a polyether ionophoric agent that is authorised as a coccidiostat for use in chickens for fattening with a maximum content of the active substance in feed of 25 mg/kg according
to Regulation (EC) No 1041/2002. Despite the requirements set for feed business operators in Regulation No (EC) 183/2005, it is generally acknowledged that under practical conditions during the
production of mixed feeds, a certain percentage of a feed batch remains in the production circuit and these residual amounts can contaminate the subsequent feed batches. This
cross-contamination may result in the exposure of non-target animal species, and hence the potential health risks for non-target animal species as well as the potential residue deposition in
foods derived from these non-target animal species have been evaluated.
Semduramicin produced toxicity typical of ionophoric compounds in dogs including skeletal muscle damage, in addition, semduramicin induces retinal changes in dogs that have not been studied in
other species yet. Studies conducted in food-producing animals regarding semduramicin toxicity are limited and mostly confined to short-term feed exposure. Based on the very limited tolerance
studies available on short-term toxicity in non-target animal species (birds (turkeys, guinea fowls, ducks and geese), rabbits and horses), adverse effects are not expected if non-target animal
species are accidentally fed a diet containing semduramicin at the maximum authorised level in feed for target animal species. In laying hens, a reduction of egg production, hatchability and
shell quality was observed in some but not all feeding experiments at concentrations equal to or exceeding 12.5 mg semduramicin/kg feed.
Cross-contamination of feed for non-target animal species at 10% (2.5 mg/kg feed) of the maximum authorised level of semduramicin could result in an intake of 0.13 mg/kg b.w. per day of
semduramicin. This level is the same as the overall NOAEL (0.125 mg/kg b.w. per day) based on changes in blood biochemistry parameters in a 2-year chronic toxicity and carcinogenicity feeding
study in rats. The CONTAM Panel concluded that adverse health effects are unlikely to occur in non-target animals as a result of cross-contamination.
No kinetic or occurrence data were available to estimate the amount of semduramicin residues in eggs, milk, meat and offal from non-target animal species. Hence, consumer exposure was estimated
using kinetic data at practical zero withdrawal time from chickens for fattening that were given the maximum authorised level of 25 mg semduramicin/kg feed. These data were extrapolated to a
concentration of 2.5 mg/kg feed to correspond to feed cross-contaminated with semduramicin at a level of 10% of the maximum authorised level. Consumption of such poultry products (100 g of
liver, 300 g muscle, 90 g skin/fat and 10 g kidney) could give an intake of 3.7?Ãƒâ€šÃ‚Âµg semduramicin equivalents (total radioactive
residues) per person corresponding to 0.062 Ãƒâ€šÃ‚Âµg/kg b.w. for a 60 kg consumer, which represents 5% of the ADI of 1.25
Ãƒâ€šÃ‚Âµg/kg b.w. per day as established by the Scientific Committee for Animal Nutrition (SCAN). Even though kinetic and tissue
deposition can differ between chickens for fattening and non-target animal species, an exceedance of the ADI is unlikely to occur. Therefore, the CONTAM Panel concluded that the very limited
data provided no indication of an appreciable risk to consumers’ health from the ingestion of semduramicin residues in products from animals exposed to feed cross-contaminated up to a
hypothetical level of 10% of the maximum authorised level.