Improvement of Nutritive Value of Rice Straw by Treatment with Ammonia and Sulphur Dioxide

An experiment was carried out to investigate the effects on the nutritive value of rice straw treated with anhydrous ammonia (30 g/kg DM) for 28 days at 20℃ and/or sulphur dioxide (40 g/kg DM) for 24 hours at 20℃. Rice straw was moistened with water (300 or 450 g/kg) prior to the treatment. In sacco digestibility of the sample was measured by suspending 5 nylon bags each for 48 hours in the rumen of Tokara goats fitted with a rumen cannular and fed on alfalfa hay. Ammonia and NH_3・SO_2 treatments improved the crude protein content of rice straw approximately by 4mfold to 45fold and the latter treatment gave slightly higher value than the former. Contents of NDF and hemicellulose were reduced by ammoniation and NH_3・SO_2 treatment, however ADF and cellulose contents were little affected. Lignin and silica contents were reduced by ammonia and NH_3・SO_2 treatments. These two treatments improved the digestibility in sacco of rice straw and its cell wall components, and straw digestibility was slightly improved with NH_3・SO_2 than with NH,. Improvement in digestibility was correlated with decrease in contents of lignin and silica and increased digestibility of lignin. Sulphuration alone less affected the nutritive value of rice straw compared to the other treatments