Effect of 3-nitrooxypropanol on methane and hydrogen emissions, methane isotopic signature, and ruminal fermentation in dairy cows

Abstract

Interpretative Summary: Effect of 3-nitrooxypropanol on ruminal fermentation, 1 methane and hydrogen emissions, and methane isotopic signature in dairy cows. By 2 Lopes et al. Page 0000. An inhibitor, 3-nitrooxypropanol, decreased by 31% enteric 3 methane and increased hydrogen emissions in lactating dairy cows, but had no effect on 4 rumen archaeal community composition nor a significant change in the isotope 5 composition of methane. Methanomicrobium) was not affected by 3NOP, but the proportion of methanogens in the 42 total cell counts tended to be decreased by 3NOP. Prevotella spp., the predominant 43 bacterial genus in ruminal contents in this experiment, was also not affected by 3NOP. 44Compared with the control, Ruminococcus and Clostridium spp. were decreased and 45Butyrivibrio spp. was increased by 3NOP. This experiment demonstrated that a 46 substantial inhibition of enteric methane emission by 3NOP in dairy cows was 47 3 accompanied with increased hydrogen emission and decreased acetate:propionate ratio, 48 but there was no effect on rumen archaeal community composition nor a significant 49 change in the isotope composition of methane. 50Key Words: methane, 3-nitrooxypropanol, rumen fermentation, dairy cow 51 52 4 INTRODUCTION 53In the rumen, methane (CH 4 ) is an end product of microbial fermentation of 54 carbohydrates and amino acids. Methanogenesis is the major sink for hydrogen in the 55 rumen, but enteric CH 4 represents also a net feed energy loss for the animal (Johnson and 56

The effects of dietary supplementation with 3-nitrooxypropanol on enteric methane emissions, rumen fermentation, and production performance in ruminants: a meta-analysis

“…2019R1F1A1056904). ments methods of CH 4 emissions among all used studies [12][13][14][15][16][17][18][19][20][21][22][23][24][25] (Table 1). In short, the administration methods of NOP were direct administration via cannula, top dressed, and mixed with diet.…”

“…The NOP is a structural analogue of methyl coenzyme-M, which inhibits the activity of methyl coenzyme-M reductase related to the final step of methanogenesis [11]. Until now, total 14 in vivo studies using NOP supplementation were performed on various domestic ruminants, including sheep [12], beef cattle [13][14][15][16][17][18][19], and dairy cattle [20][21][22][23][24][25]. According to the results of previous studies using NOP in vivo, the CH 4 emissions and proportion of acetate (% total volatile fatty acids, VFA) clearly decreased, whilst the proportion of propionate (% total VFA) significantly increased, but any adverse effects were not detected.…”

“…In a recent meta-analysis, Jayanegara et al [26] observed that increasing NOP supplementation linearly decreased CH 4 emissions regardless of type of CH 4 unit, when a meta-analysis was investigated on 10 in vivo studies [12,[16][17][18][19][20][21][22][23][24]. Dijkstra et al [27] revealed that NOP supplementation has stronger CH 4 mitigation effects in dairy cattle than in beef cattle, and those effects were decreased in increasing dietary fiber content, when a meta-analysis was conducted using 9 in vivo studies [16][17][18][19][20][21][22][23][24]. With our knowledge, there is no meta-analysis study investigating the effects of supplementation of NOP on CH 4 reduction in a long term experiment, and the changes of rumen fermentation by NOP supplementation in a related with ruminant types was not analyzed as well.…”

The geochemistry of methane isotopologues

“…5.1) that shows several insights into the origin and fate of the methane stable isotopologues in the environment. As of the time of writing, methane clumped isotoplogue data have appeared in at least a dozen articles Stolper et al, 2014a;Stolper et al, 2014b;Inagaki et al, 2015;Stolper et al, 2015;Wang et al, 2015;Douglas et al, 2016;Lopes et al, 2016;Wang et al, 2016;Young et al, 2016;Whitehill et al, 2017;Young et al, 2017). The ∆ 13 CH 3 D data were shown to be independent of and complementary to δ 13 C and δD.…”

“…C.2.1 Isolation of CH 4 using cryofocusing-preparative gas chromatography Figure C.2 shows a schematic of the methane preparation system used to isolate CH 4 for measurement of ∆ 13 CH 3 D by TILDAS at MIT from mid-2014 onwards (Inagaki et al, 2015;Wang et al, 2015;Lopes et al, 2016;Wang et al, 2016;Whitehill et al, 2017). The system consists of a cryotrapping-preparative gas chromatography system interfaced with a vacuum line and a helium supply.…”