Optimisation of treatment conditions of wheat straw with lime: Effect of concentration, moisture content and treatment time on chemical composition and in vitro digestibility

Chopped wheat straw (0.5–1.5 cm) was treated with different levels of lime (2–5% w/w), moisture (40–60%) and treatment time (1–3 weeks). Treated samples were kept in a laboratory at about 35°C in a 4×3×3 factorial arrangement, to study the effect of different factors on chemical composition and in vitro organic matter digestibity (IVOMD). Results showed that lime treatment appears to be effective in solubilising the cell wall constituents (CWC) and increasing the IVOMD significantly (P<0.01). Neutral detergent fibre (NDF) and hemicellulose (HC) contents decreased significantly (P<0.01) due to the lime treatment; and the respective decrease were to the extent of 5.40 and 16.00% in comparison to untreated wheat straw. Similarly, acid detergent lignin (ADL) was solubilised to the extent of 46.70% by lime treatment. IVOMD increased (P<0.01) with increasing concentration of lime and the maximum value (59.71%) was noticed at 5% lime concentration. The other factors like moisture content, reaction time and their interactions also showed significant effect on the enhanced solubilization of CWC. Lime (5%) with 60% moisture for three weeks reaction period was an appropriate condition for the maximum response of treatment in wheat straw under laboratory conditions.