Li Zongjun, Liu Nannan, Cao Yangchun, Jin Chunjia, Li Fei, Cai Chuanjiang, Yao Junhu
1College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi 712100 China.
2College of Pastoral Agricultural Science and Technology, Lanzhou University, Lanzhou, 730020 China.
J Anim Sci Biotechnol. 2018 Feb 9;9:21. doi: 10.1186/s40104-018-0235-3. eCollection 2018.
In rumen fermentation, fumaric acid (FA) could competitively utilize hydrogen with methanogenesis to enhance propionate production and suppress methane emission, but both effects were diet-dependent. This study aimed to explore the effects of FA supplementation on methanogenesis and rumen fermentation in goats fed diets varying in forage and concentrate particle size.
Four rumen-cannulated goats were used in a 4 × 4 Latin square design with a 2 × 2 factorial arrangement of treatments: low or high ratio of forage particle size: concentrate particle size (Fps:Cps), without or with FA supplementation (24 g/d). Fps:Cps was higher in the diet with chopped alfalfa hay plus ground corn than in that with ground alfalfa hay plus crushed corn.
Both increasing dietary Fps:Cps and FA supplementation shifted ruminal volatile fatty acid (VFA) patterns toward more propionate and less acetate in goats. An interaction between dietary Fps:Cps and FA supplementation was observed for the ratio of acetate to propionate (A:P), which was more predominant when FA was supplemented in the low-Fps:Cps diet. Methane production was reduced by FA, and the reduction was larger in the low-Fps:Cps diet (31.72%) than in the high-Fps:Cps diet (17.91%). Fumaric acid decreased ruminal total VFA concentration and increased ruminal pH. No difference was found in ruminal DM degradation of concentrate or alfalfa hay by dietary Fps:Cps or FA. Goats presented a lower ruminal methanogen abundance with FA supplementation and a higher abundance with high dietary Fps:Cps.
Adjusting dietary Fps:Cps is an alternative dietary model for studying diet-dependent effects without changing dietary chemical composition. Fumaric acid supplementation in the low-Fps:Cps diet showed greater responses in methane mitigation and propionate increase.
在瘤胃发酵中，富马酸（FA）可与甲烷生成竞争利用氢气，以提高丙酸产量并抑制甲烷排放，但这两种效应均取决于日粮。本研究旨在探讨添加FA对采食不同牧草和精料粒度日粮的山羊甲烷生成和瘤胃发酵的影响。
选用4只安装瘤胃瘘管的山羊，采用4×4拉丁方设计，处理按2×2析因排列：低或高牧草粒度与精料粒度比（Fps:Cps），不添加或添加FA（24 g/d）。与苜蓿干草粉加粉碎玉米的日粮相比，苜蓿干草切碎加玉米粉的日粮中Fps:Cps更高。
日粮Fps:Cps增加和添加FA均使山羊瘤胃挥发性脂肪酸（VFA）模式向丙酸增加、乙酸减少转变。日粮Fps:Cps与FA添加之间对乙酸与丙酸比值（A:P）存在交互作用，在低Fps:Cps日粮中添加FA时该交互作用更显著。FA降低了甲烷产量，低Fps:Cps日粮中的降低幅度（31.72%）大于高Fps:Cps日粮（17.91%）。富马酸降低了瘤胃总VFA浓度并提高了瘤胃pH值。日粮Fps:Cps或FA对瘤胃中精料或苜蓿干草的干物质降解率无影响。添加FA的山羊瘤胃产甲烷菌丰度较低，而高日粮Fps:Cps时产甲烷菌丰度较高。
调整日粮Fps:Cps是一种在不改变日粮化学成分的情况下研究日粮依赖性效应的替代日粮模式。在低Fps:Cps日粮中添加富马酸在减少甲烷排放和增加丙酸方面表现出更大的效果。
