In vitro Fermentability and Digestibility of Citronella Grass (Cymbopogon nardus) Waste Steamed and Fermented Using Different Species of White-Rot Fungi

Waste from citronella grass (Cymbopogon nardus) distillation has potential as an alternative ruminant feed, but its utilization is limited by its high lignocellulosic content, which reduces digestibility. This study evaluated the effect of fermentation using different white-rot fungi (WRF) species on the in vitro fermentability and digestibility of citronella grass waste. A Completely Randomized Design with five treatments and four replicates was used: an uninoculated control, fermentation with Trametes versicolor, Phanerochaete chrysosporium, Lentinula edodes, and a consortium of T. versicolor and P. chrysosporium. The observed parameters included dry matter and organic matter digestibility, pH, ammonia (NH3) concentration, total and partial volatile fatty acids (VFA), and total gas production. Fermentation with WRF significantly affected dry matter digestibility, organic matter digestibility, and total gas production (P<0.05) but did not significantly affect pH, NH3, or VFA concentrations (P>0.05). The control exhibited the highest digestibility and gas production values among all treatments. Nevertheless, all fermentation treatments preserved rumen fermentation conditions that supported microbial activity. Fermentation using WRF may contribute to the utilization of citronella grass waste as an alternative feed ingredient by maintaining favorable rumen fermentation conditions.