Xylanase, glucanase and xyloglucanase from Trichoderma citrinoviride DSM 33578 (4a39) for laying hens and piglets until 1 January 2036: three colorimetric methods on azurine substrates, 1500 EPU, 100 CU and 100 XGU/kg; batches had a ratio of about 7:1:1 instead of 15:1:1
Commission Implementing Regulation (EU) 2025/2503, published on 12 December 2025, authorises until 1 January 2036 a preparation of three enzymes produced by a non-genetically modified strain of Trichoderma citrinoviride DSM 33578 (holder: Huvepharma EOOD, product Huvezym® neXo) as a digestibility enhancer for poultry other than poultry for fattening and reared, and for pigs other than sows — those categories had already been authorised. After its opinions of 2022 and 2024, EFSA only in its opinion of 6 May 2025, based on new trials in laying hens and weaned piglets, considered the additive potentially efficacious in all poultry and all porcine species. The Polish title of the act reads “glwukanazy” (a typo).
- Methods in the annex (additive, premixtures and compound feed): xylanase — colorimetrically, dye released from azurine-crosslinked wheat arabinoxylan; glucanase — coloured particles from azurine-crosslinked cellulose; xyloglucanase — coloured fragments from a xyloglucan substrate. Units: 1 EPU releases 0.0083 µmol reducing sugars (as xylose) from oat spelt xylan per minute at pH 4.7 and 50 °C; 1 CU — 0.128 µmol (as glucose) from barley β-glucan at pH 4.5 and 30 °C; 1 XGU — comparison with an enzyme standard at 50 °C and pH 4.5.
- The additive (granulated or liquid) must have at least 15 000 EPU, 1000 CU and 1000 XGU/g; minimum dose 1500 EPU, 100 CU and 100 XGU/kg complete feed. In 2024 EFSA found that the batches analysed met these minima but had a xylanase:glucanase:xyloglucanase ratio of about 7:1:1 instead of the 15:1:1 of the toxicity and tolerance studies, so its conclusions apply only to the product with a 15:1:1 ratio. The annex gives only minimum activities.
- Strain: in 2022 EFSA could not confirm the species because the sequence and parameters used were not suitable for Trichoderma identification; in 2024 T. citrinoviride was confirmed by phylogenetic analysis of the genome (ITS1 and ITS2, tef1 and other marker genes). No viable cells of the strain were found in the product; dioxins (upper bound) 0.137 ng WHO-PCDD/F-TEQ/kg and 0.269 ng with PCBs. NOAEL from the subchronic study — 1000 mg/kg bw per day; maximum safe levels from 131 554 EPU/kg (chickens) to 236 200 EPU/kg (piglets).
- Efficacy: in laying hens EFSA relied on earlier studies and a new short-term trial (energy utilisation), in weaned piglets on three new long-term trials; it rejected a fourth because the copper level in the feed greatly exceeded the EU maximum. The granulated form is a skin sensitiser, the liquid form is not; both are respiratory sensitisers, neither irritates skin or eyes. The act requires respiratory and skin protection.