Effects of alkali treatment and gamma irradiation on the chemical composition and in vitro rumen digestibility of certain species of wood

Changes in the chemical composition and in vitro rumen digestibility of alder, fir, poplar and sludge were studied after treatment with NaOH and gamma irradiation. Treatment with alkali increased the percentage of cellulose and acid detergent fiber (ADF) in all species of wood studied, whereas the average acid detergent lignin (ADL) content was not affected. Alkali treatment increased the in vitro dry matter disappearance (DMD) of alder and poplar, and increased the in vitro cellulose digestion of alder, poplar and sludge. Samples of the four species of wood that were exposed to 1 × 10 8 or 2 × 10 8 rads of gamma irradiation were lower in cellulose, ADF and ADL content than the untreated samples, or those exposed to 1 × 10 6 or 1 × 10 7 rads. In vitro DMD, cellulose digestion and volatile fatty acid production were higher in samples of all four species exposed to 1 × 10 8 or 2 × 10 8 rads, than in untreated samples, or in those exposed to 1 × 10 6 or 1 × 10 7 rads.