Date palm seed-derived biochar as an environmentally sustainable feed supplement in cattle: impacts on gas production, methane emissions, fermentation parameters and performance predictions

In the context of climate change, the expanding cultivation of date palm (Phoenix dactylifera) results in substantial waste generation, posing environmental and pollution challenges. Valorization of this waste, particularly phoenix dactylifera seeds, presents a promising and eco-conscious strategy. This in vitro study innovatively evaluated the impacts of adding phoenix dactylifera seed-derived biochar (PSB) at concentrations of 0%, 1%, 2%, and 4% on gas production, methane (CH₄​) emissions, nutrient degradability, fermentation parameters, and predicted cattle performance. The results indicated that 4% PSB significantly increased gas production at 12 h of incubation (p < 0.05), while all PSB inclusion levels significantly increased it at 24 h (p < 0.05). At 36 and 48 h, the 1% PSB treatment demonstrated the highest gas production compared to the control diet (p < 0.05). The addition of 1%, 2%, or 4% PSB significantly reduced CH₄ emissions when expressed per unit of dry matter (DM) by 50.0, 53.8, and 56.6, truly degraded dry matter (TDDM) by 50.5, 56.86, and 58.03%, and as a percentage of total gas production (p < 0.01) by 54.9, 55.2, and 58.9% compared to control, respectively. In vitro dry matter degradability (IVDMD, p = 0.31) and in vitro crude fiber degradability (IVCFD, p = 0.33) were non-significantly affect by biochar inclusion. Ammonia-nitrogen (NH₃-N) concentrations were significantly higher in the 4% PSB group compared to the other groups (p < 0.01). The addition of PSB (1%, 2%, or 4%) significantly improved TVFA (measured; mmol/L) and SCFA (predicted from 24-h gas production; mmol/200 mg DM), as well as ME, OMD, and NEL compared to the control diet (p < 0.01). Overall, PSB effectively reduced CH₄ production and enhanced nutrient degradability. These findings underscore the value of using phoenix dactylifera seed-derived biochar as a sustainable and eco-friendly resource to reduce the carbon footprint of livestock production.