The effect of low temperature steam, sodium hydroxide and exogenous enzyme on in vitro degradation of rice straw by rumen bacteria of sheep

This study was conducted to evaluate the effect of low temperature steam, sodium hydroxide (NaOH) and exogenous enzyme treatment on disappearance of dry matter (DM) and neutral detergent fiber (NDF) of rice straw (RS) by in vitro rumen bacteria culture for 96 hours. The treatments were: untreated RS, RS treated with low temperature steam, RS treated with 60 g/kg DM NaOH, RS treated with 35 g/kg DM exogenous enzyme, and RS treated with low temperature steam+NaOH. The disappearance of dry matter after 96 h incubation by rumen bacteria was 60.3, 79.3, 83.1, 76.3 and 93.2 g/100g for untreated rice straw and treated with steam, NaOH, enzyme and steam+NaOH, respectively. NaOH, enzyme and or low steam caused an increase disappearance of NDF of rice straw in media culture as compared with the other samples, after 96 h culturing. The highest increase of NDF disappearance was for rice straw treated with steam+NaOH (337.3 mg/g). Therefore, it may be concluded that the growth and activity of rumen bacteria of sheep in rice straw degradation is influenced by low temperature steam, exogenous enzyme and NaOH treatment.