Supplementation with Lycium barbarum byproducts improves energy and nitrogen metabolism, and reduces methane emissions in sheep grazing alfalfa/tall fescue pastures
Xiaoyun Zhang, Wuchen Du, Kaili Xie, Lijuan Ran, Wanhe Zhu, Fujiang Hou
Abstract
Functional native herbage (FNH), rich in bioactive components and secondary metabolites, holds potential for enhancing the productivity of grazing livestock and mitigating methane (CH 4 ) emissions. The processing of Lycium barbarum yields byproducts rich in flavonoids, polysaccharides, betaine, and other bioactive compounds, which may serve as effective livestock feed additives. This study aimed to assess the effects of L. barbarum byproducts on digestion, metabolism, and CH 4 emissions in sheep grazing on sown pastures in northwest China. Twenty-four 6-month-old male sheep with similar body conditions were selected and randomly assigned to four groups ( n = 6) based on dietary treatments: an unsupplemented control group (CON), a 2.5% L. barbarum seed (LBS)-supplemented group, a 7.5% L. barbarum residue (LBR)-supplemented group, and a 2.5% L. barbarum twigs (LBT)-supplemented group. The experiment lasted for a total of 75 d. Digestive metabolism experiments and respiratory gas measurement tests were conducted. Compared to the CON group, supplementation with 2.5% L. barbarum seed or 7.5% L. barbarum residue increased ( P < 0.001) dry matter intake, ether extract intake, gross energy intake, and improved ( P < 0.001) energy utilization efficiency, including digestible energy, metabolizable energy, and net energy. Compared to the CON group, the LBS group, live weight gain increased by 44.44% ( P = 0.018), accompanied by 27.37% and 30.56% reductions in net energy requirements for maintenance and metabolizable energy requirements for maintenance, respectively. Additionally, daily CH 4 emissions and CH 4 emissions per unit grass area were reduced ( P < 0.05) by 20.34% and 20.43%, respectively. In the LBR group, live weight gain increased by 33.33% ( P = 0.018), accompanied by 46.03% and 30.56% reductions in net energy requirements for maintenance and metabolizable energy requirements for maintenance, respectively. Daily CH 4 emissions and CH 4 emissions per unit grass area were reduced ( P < 0.05) by 22.75% and 22.78%, respectively. Compared to the CON group, the live weight gain in the LBT group remained largely unchanged ( P > 0.05), while daily CH 4 emissions and CH 4 emissions per unit of grass area were reduced by 17.05% ( P < 0.05) each. The judicious application of L. barbarum byproducts in livestock production can enhance the productivity of grazing sheep, optimize resource utilization, reduce CH 4 emissions, ameliorate the ecological environment, and foster the sustainable development of animal husbandry.