Tocopherol (vitamin E) content in invasive browse species on underutilized Appalachian farmland

Abstract

The tocopherol (Vitamin E) content of forage from three invasive shrub species was measured to assess the value of the shrubs as a source of vitamin E for goats browsing on overgrown Appalachian pastures. Plant leaf clusters were collected from multiflora rose (Rosa multiflora Thunb.), autumn olive (Elaeagnus umbellata Thunb.), and Morrow's honeysuckle (Lonicera morowii Gray) in replicated plots at a site in southern West Virginia during the 1999 growing season. Alpha-, beta-, gamma-, and delta-tocopherol were extracted with hexane, separated by high performance liquid chromatography on a normal-phase diol column, and quantified. Significant differences (P<0.001) in concentration were found among species for all forms of tocopherol. Alpha-tocopherol predominated, accounting for more than 90% of the total tocopherols in all three species. Alpha-tocopherol levels increased in all species with maturity; however, the magnitude of the increase was not the same in all species. At the end of the growing season, autumn olive had the highest levels of alpha-tocopherol (1270 ± 55 ppm dry matter [DM]), followed by Morrow's honeysuckle (840 ± 55 ppm DM), and multiflora rose (610 ± 55 ppm DM). Goats grazing on mature browse may obtain adequate intake of vitamin E. High nutritive value and/or low concentrations of antiquality factors may not coincide with the high levels of vitamin E found in mature tissue, and the actual vitamin E intake will depend on the feeding behavior of the goat.