Effect of Wheat Bran Inclusion on Ensiling Quality, Nutritive Value, in vitro Fermentation Kinetics, and Methane Production of Potato Silage

Abstract

Effective preservation of high-moisture agricultural materials as silage enhances feed resource utilization and contributes to sustainable ruminant production systems. This study investigated the effects of incorporating graded levels of wheat bran (WB) on the fermentation quality, chemical composition, in vitro digestibility, gas, and methane production kinetics of potato silage. Fresh potato was ensiled with 0, 7, 15, or 30% WB (CON, WB-7, WB-15, and WB-30, respectively) on a fresh weight basis for 60 days. Increasing WB inclusion significantly improved the ensiling characteristics (P < 0.001), with the WB-30 treatment exhibiting the highest dry matter (26.75%), lowest pH (4.40), and highest Flieg score (82.50). Increasing WB proportions linearly raised crude protein (CP), ether extract (EE), neutral detergent fiber (NDF), acid detergent fiber (ADF), hemicellulose (HCEL), and cellulose (CEL) concentrations, accompanied by a decrease in nitrogen-free extract (NFE; P < 0.001). Cumulative in vitro gas production at 96 h was lower in WB-30 than in CON (70.63 vs 87.26 mL/200 mg DM; P < 0.001). Furthermore, WB-30 significantly decreased in vitro methane production to 7.81 mL/200 mg DM, achieving a 26.4% relative reduction compared with CON (P < 0.001). In vitro true digestibility (IVTD) decreased with WB addition (95.56% in CON vs. 81.93% in WB-30; P < 0.001). Organic matter digestibility (OMD), metabolizable energy (ME), and net energy for lactation (NEL) remained statistically similar across CON, WB-7, and WB-15, but were significantly lower in WB-30 (P < 0.05). Wheat bran serves as an effective moisture-absorbing additive that markedly improves the preservation quality and protein value of potato silage while mitigating ruminal methane emissions. Although a 30% WB inclusion provides optimal silage preservation and the greatest methane reduction, its associated decline in energy density and digestibility indicates a nutritional trade-off, making 15% inclusion a balanced alternative for ruminant feeding. Further in vivo evaluation is required to establish the optimal inclusion level for animal production.