Ruangyote Pilajun1*, Chittraporn Yeanpet1, Areerat Lunpha1, Wichan Kaewluan1, Rukkiat Jitchati2, Ratchataporn Lunsin3, Eric Lim Teik Chung4
1Department of Animal Science, Faculty of Agriculture, Ubon Ratchathani University, Ubon Ratchathani 34190, Thailand
2Department of Chemistry, Faculty of Science, Ubon Ratchathani University, Ubon Ratchathani 34190, Thailand
3Programs in Animal Science, Faculty of Agriculture, Ubon Ratchathani Rajabaht University, Ubon Ratchathani 34000, Thailand
4Department of Animal Science, Faculty of Agriculture, Universiti Putra Malaysia, Selangor 43400, Malaysia
*Corresponding author’s email: ruangyote.p@ubu.ac.th
Received: 04 February 2026 / Revised: 29 April 2026 / Accepted: 19 May 2026 / Published Online: 07 June 2026
Abstract
This study identified the optimal inclusion levels of fresh cassava bioethanol waste (CBW) as well as the most effective additive types based on physical properties, chemical composition, and in vitro ruminal fermentation characteristics. The experiment used a 4×4 factorial arrangement in a CRD with four CBW levels (0, 5, 10, and 15% dry matter (DM)) as well as four additive treatments (none, dry yeast, probiotics, and non-starch polysaccharides (NSP) enzymes) in fermented total mixed rations (FTMR). FTMR was ensiled for 21 days before being evaluated. Interactions between CBW levels and additives significantly affected physical scores, chemical composition, and fermentation end-products (P<0.05), but did not influence cumulative gas yield or certain gas kinetic indices (P>0.05). The addition of dry yeast increased the gas produced from the immediately soluble fraction (b) and the potential extent of gas production (P). NSP enzyme increased cumulative gas volume at 72 and 96 hours after incubation as well as the gas produced from the immediately soluble fraction (P<0.05). Addition of probiotics increased cumulative gas volumes at 72 and 96 hours, DM degradability at 24 hours, and potential extent of gas production after 96 hours of incubation (P<0.05). The inclusion of 10% CBW with probiotics or NSP enzymes yielded the highest physical quality scores. While increasing CBW levels raised fiber content and initially shifted fermentation toward higher acetic acid levels at the expense of propionate, probiotics and NSP enzymes significantly enhanced cumulative gas production and NH3-N concentrations. Remarkably, yeast and probiotics successfully redirected VFA profiles toward propionate at the 15% CBW inclusion level. Although higher CBW levels obviously reduced energy density, biological additives effectively mitigated this decline by facilitating greater fiber degradation. The results recommend inclusion of 10–15% CBW in FTMR with 10% being optimal when paired with probiotics or enzymes to improve nitrogen availability and physical quality. Further in vivo trials can validate these laboratory findings in ruminant performance.
Keywords: Cassava bioethanol waste, Saccharomyces cerevisiae, Probiotics, Fibrolytic enzymes, Ruminal fermentation
