Dietary supplementation with xylooligosaccharides and exogenous enzyme improved milk production, energy utilization efficiency and reduced enteric methane emissions of Jersey cows

Abstract

Abstract Background Sustainable strategies for enteric methane (CH4) mitigation of dairy cows have been extensively explored to improve production performance and alleviate environmental pressure. The present study aimed to investigate the effects of dietary xylooligosaccharides (XOS) and exogenous enzyme (EXE) supplementation on milk production, nutrient digestibility, enteric CH4 emissions, energy utilization efficiency of lactating Jersey dairy cows. Forty-eight lactating cows were randomly assigned to one of 4 treatments with a 2 ×2 factorial arrangement of treatments: (1) control diet (CON), (2) CON with 25 g/d XOS (XOS), (3) CON with 15 g/d EXE (EXE), and (4) CON with 25 g/d XOS and 15 g/d EXE (XOS + EXE). The 60 d experimental period consisted of a 14-d adaptation period and a 46-d sampling period. The enteric CO2 and CH4 emissions and O2 consumption were measured using the GreenFeed system, which were further used to determine the energy utilization efficiency of cows. Results Compared with CON, XOS and EXE synergistically (P < 0.05) increased milk yield, fat concentration, and energy-corrected milk yield (ECM)/DM intake, which could be reflected by the significant improvement (P < 0.05) of dietary NDF and NDF digestibility. The gaseous results showed that XOS and EXE synergistically (P < 0.05) reduced CH4 emission and CH4 emissions intensities (e.g., CH4/DM intake, CH4/milk yield, and CH4/ECM yield), whereas CO2 emission and O2 consumption remained similar among the treatments (P > 0.05). Furthermore, the synergistic effects of XOS and EXE was observed (P < 0.05) for metabolizable energy intake and CH4 energy output as a proportion of gross energy intake, whereas lowest values (P < 0.05) of CH4 energy output and CH4 energy output as a proportion of gross energy intake was observed for cows fed XOS compared with the remaining treatments. Conclusions Dietary supplementary of XOS and EXE contributed to the improvement of lactation performance, nutrient digestibility, and energy utilization efficiency, as well as reduction of enteric CH4 emissions of lactating Jersey cows. More research is also needed to investigate the long-term effect and mode of action of these additives for Jersey cows.