CAS Key Laboratory for Agro-Ecological Processes in Subtropical Region, National Engineering Laboratory for Pollution Control and Waste Utilization in Livestock and Poultry Production, South Central Experimental Station of Animal Nutrition and Feed Science in the Ministry of Agriculture, Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan, China.
College of Veterinary Science and Medicine, Central Luzon State University, Science City of Muñoz, Nueva Ecija, Philippines.
J Anim Sci. 2019 Dec 17;97(12):4999-5008. doi: 10.1093/jas/skz352.
Enteric methane (CH4) emissions are not only an important source of greenhouse gases but also a loss of dietary energy in livestock. Corn oil (CO) is rich in unsaturated fatty acid with >50% PUFA, which may enhance ruminal biohydrogenation of unsaturated fatty acids, leading to changes in ruminal H2 metabolism and methanogenesis. The objective of this study was to investigate the effect of CO supplementation of a diet on CH4 emissions, nutrient digestibility, ruminal dissolved gases, fermentation, and microbiota in goats. Six female goats were used in a crossover design with two dietary treatments, which included control and CO supplementation (30 g/kg DM basis). CO supplementation did not alter total-tract organic matter digestibility or populations of predominant ruminal fibrolytic microorganisms (protozoa, fungi, Ruminococcus albus, Ruminococcus flavefaciens, and Fibrobacter succinogenes), but reduced enteric CH4 emissions (g/kg DMI, -15.1%, P = 0.003). CO supplementation decreased ruminal dissolved hydrogen (dH2, P < 0.001) and dissolved CH4 (P < 0.001) concentrations, proportions of total unsaturated fatty acids (P < 0.001) and propionate (P = 0.015), and increased proportions of total SFAs (P < 0.001) and acetate (P < 0.001), and acetate to propionate ratio (P = 0.038) in rumen fluid. CO supplementation decreased relative abundance of family Bacteroidales_BS11_gut_group (P = 0.032), increased relative abundance of family Rikenellaceae (P = 0.021) and Lachnospiraceae (P = 0.025), and tended to increase relative abundance of genus Butyrivibrio_2 (P = 0.06). Relative abundance (P = 0.09) and 16S rRNA gene copies (P = 0.043) of order Methanomicrobiales, and relative abundance of genus Methanomicrobium (P = 0.09) also decreased with CO supplementation, but relative abundance (P = 0.012) and 16S rRNA gene copies (P = 0.08) of genus Methanobrevibacter increased. In summary, CO supplementation increased rumen biohydrogenatation by facilitating growth of biohydrogenating bacteria of family Lachnospiraceae and genus Butyrivibrio_2 and may have enhanced reductive acetogenesis by facilitating growth of family Lachnospiraceae. In conclusion, dietary supplementation of CO led to a shift of fermentation pathways that enhanced acetate production and decreased rumen dH2 concentration and CH4 emissions.
肠甲烷（CH4）排放不仅是温室气体的重要来源，也是家畜饲料能量的损失。玉米油（CO）富含不饱和脂肪酸，其中多不饱和脂肪酸（PUFA）含量超过 50%，这可能增强瘤胃不饱和脂肪酸的生物氢化作用，导致瘤胃生物氢化作用和甲烷生成过程中 H2 代谢和甲烷生成的变化。本研究旨在探讨 CO 补充日粮对山羊 CH4 排放、养分消化率、瘤胃溶解气体、发酵和微生物区系的影响。采用交叉设计，将 6 只雌性山羊分为 2 种日粮处理，包括对照和 CO 补充（以 DM 为基础添加 30 g/kg）。CO 补充并未改变总肠道有机物消化率或主要瘤胃纤维分解微生物（原生动物、真菌、Ruminococcus albus、Ruminococcus flavefaciens 和 Fibrobacter succinogenes）的种群，但减少了肠 CH4 排放（g/kg DMI，-15.1%，P=0.003）。CO 补充降低了瘤胃溶解氢（dH2，P<0.001）和溶解 CH4（P<0.001）浓度、总不饱和脂肪酸（P<0.001）和丙酸（P=0.015）的比例，增加了总 SFAs（P<0.001）和乙酸（P<0.001）的比例，以及乙酸与丙酸的比例（P=0.038）。CO 补充降低了菌门拟杆菌纲 BS11 肠群（P=0.032）的相对丰度，增加了菌科 Rikenellaceae（P=0.021）和 Lachnospiraceae（P=0.025）的相对丰度，并倾向于增加属 Butyrivibrio_2（P=0.06）的相对丰度。随着 CO 补充，目甲烷微菌目（Methanomicrobiales）的相对丰度（P=0.09）和 16S rRNA 基因拷贝数（P=0.043）以及属 Methanomicrobium（P=0.09）的相对丰度也降低，但属 Methanobrevibacter（P=0.012）的相对丰度和 16S rRNA 基因拷贝数（P=0.08）增加。总之，CO 补充通过促进产氢菌科 Lachnospiraceae 和属 Butyrivibrio_2 的生长，增加了瘤胃生物氢化作用，并可能通过促进产氢菌科 Lachnospiraceae 的生长，增强了还原乙酸生成作用。总之，日粮中 CO 的补充导致发酵途径发生变化，增加了乙酸的产生，降低了瘤胃 dH2 浓度和 CH4 排放。
