富马酸及鱼油对瘤胃微生物体外培养中亚油酸代谢生成甲烷及CLA的影响

Effects of fumaric acid and fish oil on the production of methane and CLA by linoleic acid metabolism in rumen microbial culture in vitro

文章旨在研究富马酸及富含多不饱和脂肪酸PUFA(C205,C226)的鱼油在瘤胃微生物的作用下,在富含亚油酸(Linoleic acid,C182)的红花油(safflower oil)调控脂肪酸的代谢过程中对甲烷的合成效率及其代谢机制的影响,试验分为五个处理:对照组(Control,90 ml培养液:45 ml瘤胃液+45 ml人工唾液);SO(Control+红花油120 mg);SO-FO(SO+24 mg鱼油);SO-FA(SO+24 mmol/l富马酸);SO-FO-FA(SO+24 mg鱼油+24 mmol/l富马酸)。实验结果显示:3 h培养后,与对照组、SO、SOFO处理相比,SO-FA和SO-FO-FA处理都显著提高了培养液的pH值(P<0.05)和丙酸摩尔浓度(P<0.05),但降低了丁酸的摩尔浓度(P<0.05)。与对照组相比,其它四个处理均显著提高了发酵气体产生总量(P<0.05)。其中,SO-FA和SO-FA-FO产生的发酵气体都显著高于SO和SO-FO(P<0.05)。经过12 h的培养,SO,SO-FO,SO-FA,SO-FO-FA都显著降低了甲烷气体总产量(P<0.05),其中SO-FOFA处理产生的甲烷总量最低。同时,与对照组相比,SO,SO-FO,SO-FA,SO-FO-FA的甲烷合成菌特异引物的mRNA表达量在培养6 h时显著降低(P<0.05);其中,SO-FO,SO-FA,SO-FO-FA的mRNA表达量显著低于SO处理(P<0.05)。在培养过程中,富马酸及多不饱和脂肪酸影响了红花油脂肪酸生物氢化进程:与SO相比,SO-FO,SO-FA,SO-FO-FA提高了总CLA(顺9,反11-共轭亚油酸与反10,顺12-共轭亚油酸)的浓度(P<0.05)、顺9,反11-共轭亚油酸浓度(P<0.05)和反10,顺12-共轭亚油酸浓度(P<0.05);SO-FO-FA最显著。丙酸生成前体(富马酸)和PMUF不影响瘤胃微生物的发酵作用。PMUF中有多个不饱和双键,而双键的氧化饱和作用又影响了亚油酸的生物氢化作用,从而提高了CLA的生成效率,也降低了甲烷的产量及甲烷生成菌的mRNA表达量。富马酸和PMUF的协同作用,加快代谢过程中氢的转移,使得CLA的生成量达到最高,甲烷的产量降到最低。

This paper aims to study the presence of linoleic acid(C18:5,C22:6)on safflower oil rich in linoleic acid(C18:2)under the action of rumen microorganisms(safflower oil)regulates the synthesis of methane and its metabolic mechanism in the metabolism of fatty acids.The experiment was divided into five treatments:Control group(90 ml medium:45ml tumor gastric juice+45 ml artifi.cial saliva);SO(Control+safflower oil 120 mg);SO-FO(SO+24 mg fish oil);SO-FA(SO+24 mmol/l fumaric acid);SO-FO-FA(SO+24 mg fish oil+24 mmol/l fumaric acid).The experimental results showed that,after 3 h of culture,compared with the control group,SO and SO-FO treatment,the pH value(P<0.05)and the molar concentration of propionic acid(P<0.05)were significantly increased and the molar concentration of butyric acid(P<0.05)were significantly decreased after the treatment of SO-FA and SO-FO-FA.Compared with the control group,the other four treat-ments significantly increased the total production of fermentation gas(P<0.05).The fermentation gas produced by so-fa and SO-FA-FO was significantly higher than that of SO and SO-FO.After 12 h of culture,the total production of methane gas(P<0.05)was significantly reduced by SO,SO-FO,SO-FA and SO-FO-FA(P<0.05),and the total amount of methane produced by SO-FO-FA treatment was the lowest.At the same time,compared with the control group,mRNA expression levels of methane-specific primers such as SO,SO-FO,SO-FA and SO-FO-FA were significantly reduced after 6 h of culture(P<0.05).Among them,the mRNA expression levels of SO-FO,SO-FA and SO-FO-FA were significantly lower than those of SO treatment.In the process of culture,fumaric acid and polyunsaturated fatty acids affected the biohydrogenation of safflower oil fatty acids:Compared with SO,the concentrations of total CLA(cis9,trans11-cla and trans10,cis12-cla),trans11-cla concentration(P<0.05),cis9,trans 11-claconcentration(P<0.05)andtrans10,cis12-cla concentration(P<0.05)were increased by SO-FO,SO-FA and SO-FO-FA,SO-FO-FA is the most significant.Conclusion:propionic acid production precursor(fumaric acid)and PMUF did not affect rumen microbial fermentation.There are many unsaturated double bonds in PMUF,and the oxidation saturation of the double bonds also affects the biological hydrogenation of linoleic acid,thus improving the generation efficiency of CLA,reducing the yield of methane and the mRNA expression of methane-producing bacteria.The synergistic effect of fumaric acid and PMUF accelerated the transfer of hydrogen in the metabolic process,resulting in the highest yield of CLA and the lowest yield of methane.