Decreasing methane yield with increasing food intake keeps daily methane emissions constant in two foregut fermenting marsupials, the western grey kangaroo and red kangaroo
Decreasing methane yield with increasing food intake keeps daily methane emissions constant in two foregut fermenting marsupials, the western grey kangaroo and red kangaroo
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随着食物摄入量的增加，甲烷产量减少，这使得两种前肠发酵有袋动物（西部灰袋鼠和红袋鼠）的每日甲烷排放量保持恒定
DOI：
10.1242/jeb.128165
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发表时间：
2015
影响因子：
2.8
通讯作者：
A. Munn
中科院分区：
文献类型：
--
作者：
C. Vendl;M. Clauss;Mathew Stewart;K. Leggett;J. Hummel;M. Kreuzer;A. Munn
摘要 人们认为，大足动物（袋鼠）和反刍动物之间甲烷 (CH4) 产生的根本差异与前胃微生物群组成的差异有关。我们使用六只西部灰袋鼠 (Macropus fuliginosus) 和四只红袋鼠 (Macropus rufus)，通过开路呼吸测量法测量了体内每日绝对 CH4 产量以及 CH4 产量（每单位干物质、总能量或可消化纤维摄入量的 CH4）。使用切碎的苜蓿干草饮食测试了两种食物摄入水平。特定体重的绝对 CH4 产量与先前报道的小袋鼠和非反刍草食动物（如马）的值相似，并且随食物摄入量的变化没有差异，尽管纤维消化率不会随着食物摄入量的增加而相应降低。相比之下，CH4 产量随着摄入量的增加而下降，并且介于反刍动物和非反刍食草动物报告值之间。这些结果与反刍动物和其他非反刍动物的结果相对应，其中摄入量增加（因此食糜在肠道内滞留时间较短）会导致 CH4 产量降低。我们假设，巨足动物的微生物组不是在其前肠中含有根本不同的微生物组，而是处于一种更适合生长（即生物量生产）而不是 CH4 生产的特定代谢状态。这是由于巨足类动物中的消化物保留时间短，以及大足类动物肠道中已知的独特的“消化物清洗”，其中液体的移动速度比颗粒更快，因此很可能会洗掉前胃中的微生物。尽管我们的数据表明，袋鼠仅产生反刍动物体重特定体积的 CH4 约 27%，但无论袋鼠每公斤肉排放的 CH4 量是否显着低于牛肉或羊肉生产，仍需根据物种特定的生长率和生产条件进行建模。重点文章：袋鼠的甲烷排放量与其他非反刍动物前肠发酵食草动物的甲烷排放量相当，并且可能是食糜加工的功能，而不是拥有独特的低甲烷产生微生物群落。
ABSTRACT Fundamental differences in methane (CH4) production between macropods (kangaroos) and ruminants have been suggested and linked to differences in the composition of the forestomach microbiome. Using six western grey kangaroos (Macropus fuliginosus) and four red kangaroos (Macropus rufus), we measured daily absolute CH4 production in vivo as well as CH4 yield (CH4 per unit of intake of dry matter, gross energy or digestible fibre) by open-circuit respirometry. Two food intake levels were tested using a chopped lucerne hay (alfalfa) diet. Body mass-specific absolute CH4 production resembled values previously reported in wallabies and non-ruminant herbivores such as horses, and did not differ with food intake level, although there was no concomitant proportionate decrease in fibre digestibility with higher food intake. In contrast, CH4 yield decreased with increasing intake, and was intermediate between values reported for ruminants and non-ruminant herbivores. These results correspond to those in ruminants and other non-ruminant species where increased intake (and hence a shorter digesta retention in the gut) leads to a lower CH4 yield. We hypothesize that rather than harbouring a fundamentally different microbiome in their foregut, the microbiome of macropods is in a particular metabolic state more tuned towards growth (i.e. biomass production) rather than CH4 production. This is due to the short digesta retention time in macropods and the known distinct ‘digesta washing’ in the gut of macropods, where fluids move faster than particles and hence most likely wash out microbes from the forestomach. Although our data suggest that kangaroos only produce about 27% of the body mass-specific volume of CH4 of ruminants, it remains to be modelled with species-specific growth rates and production conditions whether or not significantly lower CH4 amounts are emitted per kg of meat in kangaroo than in beef or mutton production. Highlighted Article: Methane emissions from kangaroos are comparable with those of other non-ruminant foregut fermenting herbivores, and may be a function of digesta processing rather than harbouring a unique low-methane producing microbial community.