Investigation of Eighteen Indonesian Mutant Rice Straw Varieties as Ruminant Roughage

The comparison was made between eighteen mutant and four non-mutant rice straw variety in Indonesia in terms of chemical composition, nutrient value and in vitro digestibility. The second objective was to determine the correlation between in vitro digestibility parameters and fibrous component in twenty-two Indonesian rice straw varieties. Rice straw samples were collected in triplicate from three replicate plots. The effect of variety on rice straw quality, nutrient values and in vitro digestibility was analyzed using one-way analysis of variance (ANOVA). Results demonstrated that the rice straw varieties differed (P<0.05) in relation to all nutrient and fiber fractions, except for ether extract content. Neutral detergent fiber (NDF) content was from 66.18% to 77.22%; acid detergent fiber (ADF) content was from 36.33% to 49.77% and hemicellulose content was from 21.67% to 33.84%. The NDF content of Woyla and Winongo was the lowest of all, 66.18% and 66.39%, respectively. Tropiko, as non-mutant variety, had lower ADF content (36.34%) than Inpari 32 and Ciherang. Woyla, Winongo, Diah Suci and Tropika were only varieties included in the poor class, with the RFV range by 76.94 to 80.33. The in vitro true digestibility (IVTD) of Winongo and Woyla were the highest (P<0.05). It was concluded from this study that Woyla and Winongo, as mutant varieties, provided higher nutrient value and digestibility than other varieties. Tropiko, as non-mutant variety, also had relatively great nutrient value. The digestibility of rice straw was negatively associated with NDF and ADF compounds