IN VITRO GAS PRODUCTION CHARACTERISTICS OF TREATED SAWDUST DIETS FOR SMALL RUMINANTS

Résumé

Given the increase in demand for animal feed, this study evaluated the potentials of sawdust as animal feed through in vitro assays by determining gas production at different hours during incubation and evaluating the organic matter digestibility (OMD), and short-chain fatty acids (SCFA). Sawdust from the Gmelina arborea tree was sorted from the nearby wood industry and treated differently into four treatments, T1 (wood-ash treatment), T2 (hot water treatment), T3 (caustic soda treatment), and T4 (molasses treatment). Feed samples were mixed with rumen fluid obtained from fistulated animals and a buffer solution (pH 6.8) at a ratio of 1:4 (feed to fluid); gas production was then measured at various time points for 24 hours to assess fermentability, and dry matter digestibility was determined post-incubation. The organic matter digestibility (OMD) and metabolizable energy (ME) were estimated using standard equations. The study found that wood ash and hot water treatments significantly improved gas production, having 13.33 (ml/200mg DM) and 12.33 (ml/200mg DM) respectively at 24 hours, and short-chain fatty acid (SCFA) having 0.25 (μmol/g DM) and 0.22 (μmol/g DM) with organic matter digestibility (OMD) having no significant differences across all treatments (P>0.05), indicating enhanced fermentation and nutrient availability. The wood ash treatment exhibited the highest digestibility and gas production, highlighting its effectiveness in breaking down lignocellulosic bonds. These findings suggest that treated sawdust, particularly with wood ash and hot water, can serve as a viable feed supplement for ruminants, contributing to sustainable animal nutrition.