Endo-1,4-beta- xylanase and alpha- galactosidase - 4a33

In the current application authorisation is sought under Article 4 (1) for a preparation of alpha-galactosidase and endo-1,4-beta-xylanase (Capsozyme SB Plus) under the category/functional group (4 a) "zootechnical additives"/"digestibility enhancers", according to the classification system of Annex 1 of Regulation (EC) No 1831/2003. The authorisation is sought for the use of the feed additive for chickens and minor poultry species for fattening and chickens reared for laying.

According to the Applicant, Capsozyme SB Plus is a preparation containing the following two enzymes:

- alpha-galactosidase produced by Aspergillus tubingensis (ATCC SD6740) and - endo-1,4-beta-xylanase produced by Trichoderma longibrachiatum (CBS 139997).

The Applicant expressed the alpha-galactosidase and endo-1,4-beta-xylanase activities in different units defined as follows: 

- one unit of alpha-galactosidase activity (GALU) is defined as the amount of enzyme which degrades one micromole per minute of para-nitrophenyl-alpha-D-galactopyranoside at pH 5.5 and 37 °C; and

- one unit of endo-1,4-beta-xylanase activity (AXC) is the amount of enzyme, which liberates 0.058 micromoles per minute of reducing sugars, expressed as xylose equivalents, from a wheat arabinoxylan substrate at pH 4.7 and 30 °C.

According to the Applicant, Capsozyme SB Plus has a minimum enzyme activity of 40 GALU/g for alpha-galactosidase and of 50 AXC/g for endo-1,4-beta-xylanase. The product is intended to be incorporated directly in feedingstuffs or through premixtures with the following recommended enzyme activities in feedingstuffs: 14 GALU/kg for alpha-galactosidase and 18 AXC/kg for endo-1,4-beta-xylanase.

For the quantification of the active substances in the feed additive, premixtures and feedingstuffs the Applicant submitted different single-laboratory validated and further verified colorimetric methods, based on the enzymatic hydrolysis of the correspondent substrates by alpha-galactosidase and endo-1,4-beta-xylanase. According to the results provided by the Applicant in the frame of the respective validation and verification studies, the EURL recalculated relative standard deviations for repeatability (RSDr) and for intermediate precision (RSD_ip) ranging from 1.6 to 15 % and from 1.5 to 18 %, respectively.

Based on the performance characteristics available the EURL recommends for official control the proposed single-laboratory validated and further verified colorimetric methods for the quantification of alpha-galactosidase and endo-1,4-beta-xylanase in the feed additive, premixtures and feedingstuffs.

Further testing or validation of the methods to be performed through the consortium of National Reference Laboratories as specified by Article 10 (Commission Regulation (EC) No 378/2005, as last amended by Regulation (EU) 2015/1761) is not considered necessary.

Recommended Method

as of:

- Commission Implementing Regulation (EU) 2022/1470

 For the quantification of alpha- galactosidase in the feed additive, premixtures and feedingstuffs:

colorimetric method based on the enzymatic reaction of alpha-galactosidase on the para-nitrophenyl-alpha-D- galactopyranoside substrate.

For the quantification of endo-1,4-beta- xylanase in the feed additive, premixtures and feedingstuffs: 

colorimetric method based enzymatic reaction of endo-1,4-beta-xylanase i) on a wheat arabinoxylan substrate (for the feed additive and premixtures) and ii) on an azo-xylan substrate (for feedingstuffs).