摘要:Hostazym X is an enzyme preparation of xylanase produced by a non-genetically modified strain of Trichoderma citrinoviride. The fermentation product showed negative results in a bacterial reverse mutation assay. The results of an in vitro chromosomal aberration test and of an in vivo comet assay indicate the presence of genotoxic activity in the product. Although the tolerance studies provided in target species did not indicate any adverse effect of the additive, the FEEDAP Panel, taking into account the genotoxic hazard from the product, cannot conclude on the safety of the additive for the target species. The results obtained in a subchronic rat study did not indicate any concerns for consumer safety. However, owing to the lack of information on the nature and fate of potentially genotoxic material in food derived from animals receiving the additive, the FEEDAP Panel cannot conclude on the safety of the additive for the consumer. The product should be considered a potential skin and eye irritant, and a potential skin and respiratory sensitiser. Owing to the presence of genotoxic activity in the product, any level of exposure to the additive is considered hazardous. No risks to the environment are expected to result from the use of the additive in feed, and, therefore, no further environmental risk assessment is required. Based on the results obtained in the efficacy studies, the FEEDAP Panel concludes that the additive has the potential to be efficacious in turkeys for fattening at the dose of 1 050 EPU/kg feed and in chickens for fattening, laying hens, piglets (weaned) and pigs for fattening at the dose of 1 500 EPU/kg feed. Conclusions on the efficacy can be extrapolated to minor poultry species.