Alpha-tocopherol and b-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 atocopherol 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)1 and ensiled without additive or with an inoculant or acid. Wilting decreased a-tocopherol concentration by 30% in the Bft + Ti mixture (P = 0x015). Untreated Bft + Ti silage had higher a-tocopherol content than red clover silages (56x9 vs. 34x2 mg kg)1 DM; P = 0x015). The a-tocopherol concentration of Bft + Ti silages increased during ensiling from 41x1 mg kg)1 DM in wilted herbage to 56x9, 65x2 and 56x8 mg kg)1 DM in untreated, inoculated and acid-treated silage respectively (P = 0x015). The inoculant increased a-tocopherol content in the red clover silages (50x1 vs. 34x21 mg kg)1 DM; P = 0x015) compared with untreated red clover silages. Red clover mixtures had lower b-carotene content than Bft + Ti (32Æ3 vs. 46x2 mg kg)1 DM; P = 0x016), 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.