Valorization of date pedicels via urea treatment and solid-state fermentation: Effects on nutritional composition and in vitro digestibility for ruminants Olfa Abid a,b , Itaf Chebbi b , Taha Najar b , Atef Jaouani a,* a Bioresources, Environment and Biotechnology Laboratory (LR22ES04), Higher Institute of Applied Biological Sciences of Tunis, University of Tunis El Manar, 1006, Tunis, Tunisia b Department of Animal Science, National Agronomic Institute of Tunisia, Carthage University, 1082, Tunis, Tunisia A R T I C L E INFO Keywords: White rot fungus Solid state fermentation Urea Ruminant feed Digestibility Date pedicels ABSTRACT Date pedicels (DP), an abundant by-product of date palm cultivation, are underutilized in animal feeding systems due to their high lignocellulosic content. This study aimed to enhance the nutritional value and digestibility of DP through urea treatment and solid-state fermentation (SSF) using white-rot fungi. The effects of these treatments on chemical composition, fiber fractions, and in vitro gas production were evaluated. DP were treated with urea (DPU), SSF using Fomes fomentarius and Lentinus tigrinus (DPF and DPL), and their combination (DPUF and DPUL). Crude protein (CP) content increased from 3.5 % in DP to 8.5 % in DPU. Moreover, SSF with F. fomentarius raised CP from 3.5 % in DP to 4 % in DPF and from 8.5 % in DPU to 9 % in DPUF (P < 0.001). Both urea and SSF treatments significantly reduced neutral detergent fiber (NDF) and acid detergent fiber (ADF) contents (P < 0.001). SSF was particularly effective in degrading ADF, lowering its content from 44.59 % in untreated DP to 33.18 % in DPF and 31.44 % in DPL (P < 0.05). Lignin degradation was also improved, with the acid detergent lignin (ADL) fraction in DPL decreasing from 20.04 % to 16.99 %. In vitro gas production increased significantly in all treated groups, especially in the co-treated substrates (DPUF and DPUL), indicating improved fermentability. In conclusion, the combination of urea and SSF treatments represents a promising strategy for the valorization of date pedicels. This approach improves fiber degradation and enhances the nutritional and fermentative properties of the substrate, supporting its potential use in ruminant diets. 1. Introduction In Tunisia, livestock farming has expanded since the 1970s (Ben Salem, 2011). Feed costs comprise 60–80 % of total production expenses (Rejeb Gharbi et al., 2007; Ben Rayana et al., 1994). However, the availability of local feed resources has not kept pace with the growth of livestock production, leading to a substantial gap between the nutritional needs of animals and actual intake (Ben Salem, * Corresponding author. E-mail address: atef.jaouani@issbat.utm.tn (A. Jaouani). Contents lists available at ScienceDirect Biocatalysis and Agricultural Biotechnology journal homepage: www.elsevier.com/locate/bab https://doi.org/10.1016/j.bcab.2025.103816 Received 6 April 2025; Received in revised form 16 September 2025; Accepted 7 October 2025 Biocatalysis and Agricultural Biotechnology 69 (2025) 103816 Available online 8 October 2025 1878-8181/© 2025 Elsevier Ltd. All rights are reserved, including those for text and data mining, AI training, and similar technologies.