Improving the Nutritional Value of Date Palm Leaves for Ruminants by Solid-State Fermentation with White-Rot Fungi

In recent years, the development of sustainable animal feed has turned toward bioprocessing agricultural byproducts. White-rot fungi, known for their lignin-degrading ability, represent an efficient tool to improve lignocellulosic residues for ruminant feeding. This study investigated the conversion of date palm leaves (DPL) into a nutritive feed through solid-state fermentation using Lentinus tigrinus and Fomes fomentarius for 22 days at 28 °C. Fungal biotreatment significantly improved the chemical characteristics and ruminal fermentation dynamics of DPL. The estimated crude protein content increased by 33.5% with F. fomentarius and 16.2% with L. tigrinus, while structural fiber components (NDF, ADF, ADL) were significantly reduced (P < 0.05). In vitro gas production tests revealed increased gas output and improved utilization of the insoluble substrate fraction, particularly in samples treated with L. tigrinus. Overall, fungal fermentation effectively improved the nutritional value and digestibility of DPL, demonstrating its potential as a sustainable alternative feed for ruminants.