Alpha-tocopherol and beta-carotene in legume-grass mixtures as influenced by wilting, ensiling and type of silage additive

Summary

Effects of wilting, ensiling and type of additive on a-tocopherol and b-carotene contents in legume–grass mixtures were examined. Swards of birdsfoot trefoil + timothy (Bft + Ti), red clover + timothy (Rc + Ti)and red clover + meadow fescue (Rc + Mf) were harvested as a first regrowth in August 2005. Forage was wilted to a dry-matter (DM) content of 273 g/kg and ensiled without additive or with an inoculant or acid. Wilting decreased a-tocopherol concentration by 30% in the Bft + Ti mixture (P = 0.015). Untreated Bft + Ti silage had higher a-tocopherol content than red clover silages (56.9 vs. 34.2 mg/kg DM; P = 0.015). The a-tocopherol concentration of Bft + Ti forages increased during ensiling from 41.1 mg/kg DM in wilted herbage to 56.9, 65.2 and 56.8 mg/kg DM in untreated, inoculated and acid-treated silage respectively(P = 0.015). The inoculant increased a-tocopherol content in the red clover silages (50.1 vs. 34.2 mg/kg DM; P = 0.015) compared with untreated red clover silages. Red clover mixtures had lower b-carotene content than Bft + Ti (32.3 vs. 46.2 mg/kg DM; P = 0.016), averaged over treatments. In conclusion, wilting had small effects but the use of bacterial inoculant as an additive and a Bft + Ti mixture increased a-tocopherol concentration in the silage.