Scientific Opinion on the safety and efficacy of Toyocerin? (Bacillus toyonensis) as a feed additive for chickens for fattening, weaned piglets, pigs for fattening, sows for reproduction, cattle for fattening and calves for rearing and for rabbits for fattening

摘要

Toyocerin? is a feed additive based on a strain originally defined as Bacillus cereus and now re‐assigned to Bacillus toyonensis. It was subject to re‐evaluation in 2012. Following the publication of the EFSA opinion and the concerns expressed therein regarding the safety of Toyocerin?, the Commission adopted a Regulation which suspended the existing authorisations of the additive. The applicant was given the possibility to submit supplementary data which might allow a re‐consideration of the assessment published by EFSA in 2012. The applicant has therefore submitted further data and arguments. B. toyonensis is resistant to chloramphenicol and tetracycline and harbours catQ and tet(M), known acquired resistance genes to these antibiotics. The role of chromosomal genes coding for chloramphenicol acetyl transferase, the major facilitator superfamily transporter and the plasmid‐encoded proteins in the gerIC–nucB locus, potentially contributing to or enhancing the observed resistance, has not been established. On the basis of the data provided by the applicant, including the latest submissions, the FEEDAP Panel concludes that B. toyonensis poses a risk for the spread of genes coding for resistance to tetracycline and chloramphenicol, antibiotics of human and veterinary importance. B. toyonensis harbours complete nhe and hbl operons, coding for non‐haemolytic and haemolytic enterotoxins, with all genes in the correct orientation, and no insertions, deletions or mutations affecting their transcription, translation or secretion detected. The strain can produce and release cytotoxic agents, but less effectively than the B. cereus group strains selected as positive controls and under the conditions tested. B. toyonensis has the capacity to elaborate functional toxins and thus, to pose a risk to humans exposed to the organism. Toyocerin? has the potential to improve performance of weaned piglets at the minimum recommended dose of 0.5 × 109 colony‐forming units (CFU)/kg feed. B. toyonensis is compatible with all tested coccidiostats except for salinomycin sodium and semduramycin sodium.