Dietary Date Palm Leaves Ensiled with Fibrolytic Enzymes Decreased Methane Production, and Improved Feed Degradability and Fermentation Kinetics in A Ruminal In Vitro System

Abstract

Purpose: The present experiment aimed to evaluate date palm leaves (DPL) treated without or with fibrolytic enzymes as a feed for ruminants. Methods: The experiment employed an in vitro wireless gas production system to evaluate the dietary inclusion of DPL as sun-dried, DPL ensiled without or with fibrolytic enzymes for 45 days. The different forms of DPL replaced berseem hay (300 g/kg diet) at 0, 25, 50, 75 and 100% in the diet. Results: Dried DPL linearly decreased the asymptotic total gas production (GP), rate of methane (CH4) and carbon dioxide (CO2) production, and acid detergent fiber degradability, and increased the lag of total GP (P < 0.05). The ensiled DPL also linearly decreased (P < 0.05) the asymptotic total GP, asymptotic CH4, asymptotic CO2 production and the rate of CH4 and CO2 productions, but dry matter degradability and total volatile fatty acid (VFA) concentrations were unaffected. Date palm leaves treated with fibrolytic enzymes linearly decreased the asymptotic total GP, CH4 and CO2 productions, and the rate of CH4 and CO2 production. Ensiling of DPL with fibrolytic enzymes increased (P < 0.05) dry matter and fiber degradability and the concentrations of ruminal ammonia-N and total VFA. Conclusion: It is concluded that DPL treated with fibrolytic enzymes can replace berseem hay up to 100% in the diet to reduce CH4 production from ruminants. Ensiling with fibrolytic enzymes is recommended as a sustainable strategy to reduce environmental pollution and utilization of DPL. Graphical Abstract: [Figure not available: see fulltext.]