Efficacy of RONOZYME® WX (endo‐1,4‐β‐xylanase) as a feed additive for laying hens

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Published on: Thu, 28 Nov 2019

RONOZYME^®WX is an additive that contains endo‐1,4‐β‐xylanase which is authorised for use as a feed additive in poultry for fattening, weaned piglets and pigs for fattening. The Panel on additives and Products or Substances used in Animal Feed (FEEDAP) delivered in 2012 an opinion on the safety and efficacy of RONOZYME^®WX when used as a feed additive for poultry, piglets (weaned) and pigs for fattening and another one in 2016 on the change of the production strain proposed by the applicant. In those opinions, the FEEDAP Panel concluded that the use of the product as a feed additive raise no concerns for consumer safety or for the environment. Considering the safety for the user, the Panel concluded that the additive is not a skin or eye irritant but could not conclude on the skin sensitisation potential of the additive, however, and owing to the proteinaceous nature of the active substance the additive was considered a potential respiratory sensitiser. In a further application, the applicant requested the use of the additive in laying hens. The tolerance trial provided for that assessment allowed to conclude that the additive is safe for laying hens under the recommended conditions of use. In the same application and in order to support the efficacy of the additive in laying hens, the applicant submitted three long‐term trials. In all three trials, the groups receiving the xylanase at the recommended dose showed a lower feed intake and a better feed to egg mass ratio. However, in one of the three trials, these reductions were seen concurrently with a decrease in the laying rate. This result casted doubts on the efficacy of the additive, and therefore, the Panel considered that there was not sufficient evidence to conclude on the efficacy of the product. The applicant provided a further efficacy trial in which the results showed that the hens that received the additive had a better laying performance at the recommended level of 100 FXU/kg and allowed the Panel to conclude that the additive is efficacious as a zootechnical additive in laying hens.