- 2 september 2010 (Senaste uppdatering: 6 juni 2016)
For characterisation of endo-1,4-beta-xylanase activity:
- colorimetric method measuring water soluble dye released by action of endo-1,4-β-xylanase from azurine cross-linked wheat arabinoxylan substrates
In the current application authorisation is sought for Hostazym X under article 4(1) and article 10(2) for Hostazym X under the category "zootechnical additives", functional groups 4(a) "digestibility enhancers", according to Annex I of Regulation (EC) No 1831/2003. The authorisation for chickens for fattening, turkeys for fattening, laying hens, weaned piglets, pigs for fattening and other birds for fattening or laying is requested. Hostazym X contains endo-1,4-b-xylanase (EC 184.108.40.206) as active agent, produced by the strains of Trichoderma longibrachiatum (IMI 356040). This feed additive is already authorised with the number E 1617 by the Commission Regulations (EC) 2148/2004, (EC) 828/2007 and (EC) 322/2009.
The enzymatic activity of endo-1,4-b-xylanase is expressed in endo-pentosanase units (EPU). According to the applicant, one EPU is the amount of enzyme which releases 0.0083 μmol of reducing sugars (xylose equivalent) per minute from oat spelt xylan at pH 4.7 and 50 °C.
The product is intended to be marketed as solid (Hostazym X Microgranulate) and liquid (Hostazym X Liquid) formulations used in compound feed rich in non-starch polysaccharides (mainly arabinoxylans). Two solid formulations have a guaranteed minimum activity of endo-1,4-b-xylanase of 6000 and 30000 EPU/g. Two liquid formulations have a guaranteed minimum activity of endo-1,4-b-xylanase of 6000 and 15000 EPU/g. Hostazym X is intended to be mixed into premixtures and/or complete feedingstuffs: to obtain minimum activities of endo-1,4-b-xylanase in feedingstuffs of:
- 1050 EPU/kg for turkeys for fattening, laying hens and other birds for fattening or laying, and
- 1500 EPU/kg for chickens for fattening, weaned piglets and pigs for fattening.
For the determination of the activity of endo-1,4-b-xylanase in the feed additive, premixtures and feedingstuffs, the applicant proposes a single laboratory validated and further verified colorimetric methods based on the quantification of water soluble dyed fragments produced by the action of endo-1,4 b-xylanase on commercially available azurine cross-linked wheat arabinoxylan substrates. Enzymatic activity of the sample is calculated using a reference enzyme standard, available from the applicant upon request. The following method performance characteristics were derived from the validation and verification studies: for the feed additive: - a relative standard deviation for repeatability (RSDr) ranging from 1.9 to 3.3 %; - a relative standard deviation for intermediate precision (RSDint) ranging from 1.9 to 3.3 %; and - a recovery rate (RRec) ranging from 101 to 104 %; for premixtures: - RSDr ranging from 3.2 to 8.2 %; - RSDint = 3.2 %, and - RRec ranging from 96 to 103 %; for feedingstuffs: - RSDr ranging from 7.6 to 16 %; - RSDint ranging from 8.9 to 16 %; ‑ RRec ranging from 93 to 112 %; - a limit of detection (LOD) and quantification (LOQ) of 107 and 358 EPU/kg, respectively.
Based on the satisfactory performance characteristics mentioned above, the CRL recommends for official control the single laboratory validated and further verified colorimetric methods submitted by the applicant for the determination of the activity of endo-1,4-b-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) is not considered necessary.