Effects of Glycerol Fatty Acid Esters on Growth Performance, Methane Emissions, and Rumen Microbial Flora of Dabieshan Beef Cattle

Glycerol fatty acid esters (GFAEs) exhibit potential applications in ruminant production, including enhancing animal performance, improving nutrient utilization, and modulating rumen function. However, studies on indigenous Dabieshan beef cattle are lacking. This study aimed to evaluate GFAE's effects on their performance, meat quality, and rumen function. Thirty 2-year-old cattle (294.73 ± 3.21 kg; mean ± SD), were randomly divided into three groups (<i>n</i> = 10): on a dry matter (DM) basis, CON (basal diet), 0.05 GFAE (basal + 0.05% GFAE), 0.1 GFAE (basal + 0.1% GFAE), fed for 60 days. The crude protein (CP) digestibility of the 0.05 GFAE group showed a significant 4.55% increase compared with the CON group, while that of the 0.1 GFAE group was significantly elevated by 2.76% relative to the CON group. For key meat quality indices of Dabieshan beef cattle, compared with the CON group, the 0.05 GFAE and 0.1 GFAE groups showed increases in L value by 10.14% and 7.11%, respectively (<i>p</i> = 0.042); decreases in shear force by 5.24% and 1.48%, respectively (<i>p</i> = 0.024); and increases in ether extract(EE) content by 10.91% and 2.33%, respectively (<i>p</i> = 0.019). Compared with the CON group, the 0.05 GFAE and 0.1 GFAE groups showed significant alterations in key serum biochemical indices of Dabieshan beef cattle: TP (total protein) levels elevated significantly by 6.44% and 13.04%, respectively (<i>p</i> = 0.010); total antioxidant capacity (T-AOC) increased significantly by 33.96% and 46.23%, respectively (<i>p</i> = 0.001); UREA concentrations decreased significantly, by 22.67% and 33.53%, respectively (<i>p</i> = 0.002); superoxide dismutase (SOD) activity rose significantly, by 7.30% and 7.99%, respectively (<i>p</i> = 0.020); and malondialdehyde (MDA) content declined significantly, by 20.25% and 28.03%, respectively (<i>p</i> = 0.040). Relative to the CON group, dietary supplementation with GFAE significantly increased ruminal butyrate concentrations, with the 0.05 GFAE and 0.1 GFAE supplemented groups exhibiting respective increments of 17.38% and 18.03% (<i>p</i> = 0.025). Both Groups 0.05 GFAE and 0.1 GFAE reduced CH4 emissions (<i>p</i> = 0.005) and elevated <i>Prevotella</i> abundance (<i>p</i> = 0.001). The study findings revealed that dietary supplementation with GFAE at concentrations of 0.05% and 0.1% of dry matter resulted in substantial decreases in daily methane emissions, representing respective reductions of 6.91% and 11.63% compared to the control group (<i>p</i> = 0.005). At the species level of the rumen microbial community, the relative abundance of the genus <i>Prevotella</i>_sp. was significantly elevated by 60.52% and 38.48% in the 0.05 GFAE and 0.1 GFAE groups, respectively, when contrasted with the CON group (<i>p</i> = 0.001). Collectively, these results demonstrate that the inclusion of dietary 0.05% GFAE supplementation conferred multifaceted benefits to Dabieshan beef cattle, thereby highlighting its potential as a viable strategy to enhance the sustainability of beef cattle production systems.