Abstract
Cylactin® is a product consisting of viable cells of Enterococcus faecium. The product strain was found to beresistant to kanamycin. A detailed study of the nature of kanamycin resistance demonstrated the absence ofknown acquired genes coding for aminoglycosides‐modifying enzymes. Two genetic determinants, theaminoglycoside acetyltransferase gene aac(6’)‐li and the gene sfkmr, both intrinsic to E. faecium, were shown tocontribute to the resistance to kanamycin. In the view of the FEEDAP Panel, the resistance of this strain of E.faecium is most likely to be caused by an unknown mechanism that potentiates the effect of the sfkmr gene, andnot by acquisition of resistance genes, and thus is not a cause for concern. When used at 100 times therecommended level, Cylactin® did not show any adverse effect on performance or mortality of chickens forfattening. Therefore, the additive is safe for the target animals at the proposed conditions of use. E. faeciumNCIMB 10415 is free of known enterococcal virulence factors. No other concerns for consumer safety wereidentified. Cylactin® is not a skin/mucosal irritant or skin sensitiser. As the product is formulated with a largeparticle size and the dusting potential is low, inhalation exposure of users will be minimal. Cylactin® isefficacious in chickens for fattening as demonstrated in three trials showing an increase in final body weightwhen diets were supplemented at or close to the minimum recommended dose (0.3 × 109 CFU/kg feed). Cylactin® is compatible with decoquinate, monensin, robenidine, diclazuril and semduramycin.
Keywords: Zootechnical additive, gut flora stabilisers, Cylactin®, Enterococcus faecium, kanamycin resistance, chickens for fattening, safety, efficacy, compatibility
EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) ; Scientific Opinion on the safety and efficacy of the product Cylactin® (Enterococcus faecium) as a feed additive for chickens for fattening. EFSA Journal 2010;8(7):1661. [13 pp.]. doi: 10.2903/j.efsa.2010.1661
Panel members: Gabriele Aquilina, Georges Bories, Paul Brantom, Andrew Chesson, Pier Sandro Cocconcelli, Joop de Knecht, Noël Albert Dierick, Mikolaj Antoni Gralak, Jürgen Gropp, Ingrid Halle, Reinhard Kroker, Lubomir Leng, Sven Lindgren, Anne‐Katrine Lundebye Haldorsen, Alberto Mantovani, Miklós Mézes, Derek Renshaw and Maria Saarela.
Correspondence: feedap@efsa.europa.eu
Acknowledgement: The Panel wishes to thank the members of the Working Group on Micro‐organisms, including Guido Rychen and Atte von Wright, for the preparation of this opinion.
Adoption date: 22 June 2010
Published date: 9 July 2010
Question number: EFSA‐Q‐2008‐422
On request from: European Commission
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