Effects of gallic acid on in vitro rumen fermentation and methane production using rumen simulation (Rusitec) and batch-culture techniques
Effects of gallic acid on in vitro rumen fermentation and methane production using rumen simulation (Rusitec) and batch-culture techniques
复制标题
使用瘤胃模拟 (Rusitec) 和分批培养技术，没食子酸对体外瘤胃发酵和甲烷产生的影响
DOI：
10.1071/an17365
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发表时间：
2019-01-01
影响因子：
1.4
通讯作者：
Zhao, G. Y.
中科院分区：
文献类型：
--
作者：
Wei, C.;Guyader, J.;Zhao, G. Y.
本研究通过两个试验研究了在反刍动物日粮中添加没食子酸（GA）对体外瘤胃发酵和甲烷（CH 4）产生的长期和短期影响，并探讨了GA和乙醇对发酵的可能相互作用。第一个实验使用瘤胃模拟技术（Rusitec）进行，作为完全随机区组设计，具有四个重复和以下四种剂量的GA：0、5、10和20 mg GA/g干物质（DM）。在所有处理中使用乙醇以增加GA在瘤胃液中的溶解。试验期为16 d，其中前7 d为适应期，后9 d为取样期。第二个实验是48小时的分批培养孵育，作为一个完全随机化的设计与4（GA剂量; 0，10，20，和40毫克GA/克DM）× 2（有或无乙醇）安排的治疗。在Rusitec试验中，GA添加量达到20 mg/g DM时，DM消失率（DMD）、有机质（OM）消失率、中性洗涤纤维消失率（NDFD）、酸性洗涤纤维消失率（ADFD）和淀粉消失率均不受影响（P > 0.05），但粗蛋白质消失率从78.3%线性下降（P = 0.04）至72.0%。添加GA对产气量和甲烷产量（以mL/gDM和mL/gDMD表示）无显著影响（P > 0.05）。添加GA至20 mg/gDM时，丁酸和异戊酸产量增加（P < 0.05），异丁酸产量增加（P = 0.09），庚酸产量减少（P = 0.07）。在分批培养试验中，添加GA至40 mg/g DM时，48 h DMD、NDFD和ADFD均呈线性增加（P <0.05），CH 4以mL/g DMD、mL/g NDFD和mL/g ADFD表示均呈线性减少（P < 0.05）。只有当GA以10 mg/g DM添加而无乙醇时，24 h和48 h后甲烷产量才有所下降。随着GA浓度的增加，发酵液pH值和氨氮浓度也显著降低（P < 0.05）。乙醇处理显著提高了48 h DMD、NDFD、ADFD、产气量（mL/g DM、mL/g OM或mL/g DMD）、CH 4产量（mL/g DM、mL/g DMD或mL/g NDFD）、总挥发性脂肪酸浓度、乙酸/丙酸比、乙酸、戊酸、异戊酸和己酸的摩尔比（P < 0.01），降低了丙酸、丁酸和异丁酸的摩尔比（P < 0.01）。仅对于乙酸盐摩尔比例观察到显著剂量的GA x乙醇相互作用（P = 0.03）。总之，我们的研究表明，GA对饲料消化和CH 4产生的有益影响可能是短期的，而改善N代谢可能是长期持续的。这可能是有用的，进行长期的体内研究，使用一系列的饮食和剂量，以验证是否GA可以用作饲料添加剂，以减轻肠道CH 4的生产和改善反刍动物的N代谢。
Two experiments were conducted to investigate the effects of adding gallic acid (GA) to ruminant diets on long- and short-term in vitro rumen fermentation and methane (CH4) production, and to test possible interactions between GA and ethanol on fermentation. The first experiment was conducted using the rumen simulation technique (Rusitec), as a completely randomised block design with four replications and the following four doses of GA: 0, 5, 10 and 20 mg GA/g dry matter (DM). Ethanol was used in all treatments to increase the solubilisation of GA in rumen fluid. The experimental period lasted 16 days, of which the first 7 days were for adaptation and the subsequent 9 days were for sampling. The second experiment was a 48-h batch-culture incubation conducted as a completely randomised design with a 4 (GA dose; 0, 10, 20, and 40 mg GA/g DM) x 2 (with or without ethanol) arrangement of treatments. In the Rusitec experiment, addition of GA up to 20 mg/g DM did not affect DM disappearance (DMD), organic matter (OM) disappearance, neutral detergent-fibre disappearance (NDFD), acid detergent-fibre disappearance (ADFD) or starch disappearance (P > 0.05), but crude protein disappearance was linearly decreased (P = 0.04) from 78.3% to 72.0%. Daily gas production and CH4 production expressed as mL/g DM and mL/g DMD were not affected by addition of GA (P > 0.05). Addition of GA up to 20 mg/g DM increased butyrate and isovalerate production (P < 0.05) and tended to increase isobutyrate (P = 0.09) and decrease heptanoate production (P = 0.07). In the batch-culture experiment, adding GA up to 40 mg/g DM linearly increased 48-h DMD, NDFD and ADFD (P < 0.05) and decreased (P < 0.05) CH4 expressed as mL/g DMD, mL/g NDFD and mL/g ADFD. Methane production was decreased after 24 h and 48 h only when GA was added at 10 mg/g DM without ethanol. Fermentation liquid pH and concentration of ammonia-nitrogen (ammonia-N) were also reduced (P < 0.05) with an increasing concentration of GA. Treatments with ethanol notably enhanced 48-h DMD, NDFD, ADFD, gas production (mL/g DM, mL/g OM or mL/g DMD), CH4 production (mL/g DM, mL/g DMD or mL/g NDFD), total volatile fatty acid concentration, the acetate:propionate ratio, acetate, valerate, isovalerate and caproate molar proportions (P < 0.01) and decreased propionate, butyrate and isobutyrate molar proportions (P < 0.01). Significant dose of GA x ethanol interaction was observed only for acetate molar proportion (P = 0.03). In conclusion, our study suggests that the beneficial effects of GA on feed digestion and CH4 production may be short term, while improvements in N metabolism may be sustained over the long term. It may be useful to conduct long-term in vivo studies using a range of diets and doses to verify whether GA can be used as a feed additive to mitigate enteric CH4 production and improve N metabolism of ruminants.