The effects of fermentation using gamma-irradiated Aspergillus niger and adding rice bran on rice straw digestibility: in vitro study

Abstract

Abstract This study aimed to evaluate the in vitro digestibility of rice straw fermented with gamma-irradiated Aspergillus niger. This study was also determined to evaluate the in vitro digestibility of the combination fermented rice straw and rice bran as ruminant rations. A 500 Gy gamma-irradiated A. niger was used for the fermentation process in rice straw by 21 days. Completely randomized design with six treatments and four replications was applied in this study. The treatments were: JNF (rice straw), JF (fermented rice straw), JNF 85 (85% rice straw + 15% rice bran), JF 85 (85% fermented rice straw + 15% rice bran), JNF 70 (70% rice straw + 30% rice bran), JF 70 (70% fermented rice straw + 30% rice bran). The observed variables were the nutrient content, in vitro gas production and in vitro true digestibility (IVTD). The results showed that fermentation treatment by gamma-irradiated A. niger could reduce ADF content of rice straw (P<0.05). however, there was no significant difference in NDF content. JF 70 treatment produced the highest in vitro gas production (P<0.05). JF 70 also produced the highest IVTD (P<0.05). in conclusion, fermentation treatment by gamma-irradiated A. niger could reduce ADF content and increase IVTD. Adding rice bran in ruminant rations was also increase the availability of soluble nutrients for rumen microbes.