Scientific opinion on the safety and efficacy of Ronozyme WX (endo-1,4-beta-xylanase) as a feed additive for poultry, piglets (weaned) and pigs for fattening

Zootechnical additive, digestibility enhancer, safety, efficacy, poultry, pigs
First published in the EFSA Journal
20 July 2012
12 June 2012
Scientific Opinion


Ronozyme WX is a preparation of endo-1,4-beta-xylanase produced by a genetically modified strain of Aspergillus oryzae and is presented in two forms, coated (CT) and liquid (L). The solid and liquid forms of the additive are considered equivalent in terms of safety and efficacy at the same dose. The final enzyme preparations contain no cultivable production organisms or recombinant DNA, given the limits of detection and evidence for the presence of deoxyribonuclease activity. The use of Ronozyme WX is safe at the maximum proposed dose for chickens and turkeys for fattening and piglets. This conclusion allows extrapolation to all minor poultry species for fattening and can be extended to pigs for fattening. Ronozyme WX is not genotoxic and no adverse effects were reported in a 90-day oral toxicity study. Therefore, the use of Ronozyme WX as a feed additive is not considered to pose a risk to consumers of animal products derived from animals treated with the additive. No studies of the additive that are relevant to user safety were carried out. However, the enzyme concentrate in Ronozyme WX was tested and was found not to be irritant to skin or eyes. In the absence of data, and given the nature of the product, it should be treated as a potential skin/respiratory sensitiser. The active ingredient of Ronozyme WX is a protein and as such will be degraded/inactivated during passage through the digestive tract of animals. Therefore, no risks to the environment are expected. The efficacy of Ronozyme WX has been demonstrated in chickens, turkeys and ducks for fattening at a minimum proposed dose of 100 FXU/kg complete feed. This conclusion can be extended to all minor poultry species for fattening. Efficacy has also been demonstrated in piglets and in pigs for fattening at a minimum dose of 200 FXU/kg complete feed.

Panel members at the time of adoption

Gabriele Aquilina, Georges Bories, Andrew Chesson, Pier Sandro Cocconcelli, Joop de Knecht, Noël Albert Dierick, Mikolaj Antoni Gralak, Jürgen Gropp, Ingrid Halle, Christer Hogstrand, the late Reinhard Kroker, Lubomir Leng, Secundino López Puente, Anne-Katrine Lundebye Haldorsen, Alberto Mantovani, Giovanna Martelli, Miklós Mézes, Derek Renshaw, Maria Saarela, Kristen Sejrsen and Johannes Westendorf
Panel on Additives and Products or Substances used in Animal Feed
EFSA Journal 2012;10(7):2790
Question Number
On request from
European Commission