Article

Responses in digestion, rumen fermentation and microbial populations to inhibition of methane formation by a halogenated methane analogue

National Institute of Livestock and Grassland Science, Tsukuba, Ibaraki 305-0901, Japan.
The British journal of nutrition (Impact Factor: 3.45). 11/2011; 108(3):482-91. DOI: 10.1017/S0007114511005794
Source: PubMed

ABSTRACT

The effects of the anti-methanogenic compound, bromochloromethane (BCM), on rumen microbial fermentation and ecology were examined in vivo. Japanese goats were fed a diet of 50 % Timothy grass and 50 % concentrate and then sequentially adapted to low, mid and high doses of BCM. The goats were placed into the respiration chambers for analysis of rumen microbial function and methane and H2 production. The levels of methane production were reduced by 5, 71 and 91 %, and H2 production was estimated at 545, 2941 and 3496 mmol/head per d, in response to low, mid and high doses of BCM, respectively, with no effect on maintenance feed intake and digestibility. Real-time PCR quantification of microbial groups showed a significant decrease relative to controls in abundance of methanogens and rumen fungi, whereas there were increases in Prevotella spp. and Fibrobacter succinogenes, a decrease in Ruminococcus albus and R. flavefaciens was unchanged. The numbers of protozoa were also unaffected. Denaturing gradient gel electrophoresis and quantitative PCR analysis revealed that several Prevotella spp. were the bacteria that increased most in response to BCM treatment. It is concluded that the methane-inhibited rumen adapts to high hydrogen levels by shifting fermentation to propionate via Prevotella spp., but the majority of metabolic hydrogen is expelled as H2 gas.

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Available from: Christopher S Mcsweeney, Jul 15, 2014
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    • "The use of specific CH 4 inhibitors has been related to H 2 accumulation both in vitro (Immig et al., 1996; Soliva et al., 2011; O'Brien et al., 2014) and in vivo using direct measurement (Immig et al., 1996; Mitsumori et al., 2012), or stoichiometric calculation (Mitsumori et al., 2012; Romero-Perez et al., 2015). The accumulation of H 2 observed in the present experiment indicates a redirection of MH which is in agreement with previous observations using CH 4 inhibitors (Immig et al., 1996; Soliva et al., 2011; Mitsumori et al., 2012; O'Brien et al., 2014). "
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    ABSTRACT: The purpose of this study was to evaluate the effect of different doses of 3-nitrooxypropanol (NOP) to a backgrounding diet on methane (CH4) emissions using the in vitro rumen simulation technique (Rusitec). 3-Nitrooxypropanol is an enzymatic inhibitor that has consistently reduced CH4 emissions in sheep, dairy and beef cattle (up to 59% reduction on a long term basis). Two Rusitec apparatuses each equipped with 8 fermenters were used in a completely randomized block design with 2 blocks (apparatus) and 4 treatments: 0, 5, 10 and 20mg of NOP. Within each apparatus, 2 fermenters were randomly assigned to a treatment. Treatments were supplied daily with 10g of diet (6g of barley silage, 3.5g of barley grain and 0.5g of supplement; dry matter [DM] basis). The experiment included an adaptation period without treatment supplementation (8 days) and a treatment period (7 days) with NOP addition. 3-Nitrooxypropanol did not affect dry matter (DMD; P =0.79) or organic matter disappearance (OMD; P =0.50) but reduced CH4 production (mLg-1 DM) by up to 86.2% (P <0.01). Total volatile fatty acid (VFA) concentration was not affected (P =0.99) but a reduction in acetate molar proportion was observed (P <0.01) together with an increase of isovalerate (P <0.01) and a linear increase of the sum of propionate, butyrate and valerate (P+B+V; P =0.01). A reduction in the molar proportion of metabolic hydrogen (MH) used for CH4 production was observed with concomitant increase of MH used for VFA (P <0.01) and H2 (P <0.01) synthesis. Total copy number of 16S rRNA genes for methanogens and bacteria in the liquid phase, and total copy number of 16S rRNA gene for bacteria in the solid phase were not affected by NOP (P >0.12); however, that for methanogens in the solid phase was reduced (P <0.01). Total protozoal cells were not affected (P =0.61). Results showed that NOP addition to a backgrounding diet is an effective means of reducing CH4 production in vitro; however, less than 5mg of NOP should be used in further studies when using Rusitec fermenters to better simulate in vivo conditions where much lower levels are used. The redirection of MH, mainly to VFA synthesis, when CH4 production was inhibited could be beneficial for animal production when supplementing NOP; however, the accumulation of H2 represents a loss of energy utilizable by cattle from feed.
    Full-text · Article · Sep 2015 · Animal Feed Science and Technology
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    • "It is possible that not all individuals within a herd respond in the same manner to NOP and the possibility that some animals may exhibit adaptation over time cannot be discounted. When evaluating the effects of providing goats with BCM, Mitsumori et al. (2012) "
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    ABSTRACT: The objective was to evaluate whether long-term addition of 3-nitrooxypropanol (NOP) to a beef cattle diet results in a sustained reduction in enteric CH emissions in beef cattle. Eight ruminally cannulated heifers (637 ± 16.2 kg BW) were used in a completely randomized design with 2 treatments: Control (0 g/d of NOP) and NOP (2 g/d of NOP). Treatments were mixed by hand into the total mixed ration (60% forage, DM basis) at feeding time. Feed offered was restricted to 65% of ad libitum DMI (slightly over maintenance energy intake) and provided once per day. The duration of the experiment was 146 d, including an initial 18-d covariate period without NOP use; a 112-d treatment period with NOP addition to the diet, divided into four 28-d time intervals (d 1 to 28, 29 to 56, 57 to 84, and 85 to 112); and a final 16-d recovery period without NOP use. During the covariate period and at the end of each interval and the end of the recovery period, CH was measured for 3 d using whole animal metabolic chambers. The concentration of VFA was measured in rumen fluid samples collected 0, 3, and 6 h after feeding, and the microbial population was evaluated using rumen samples collected 3 h after feeding on d 12 of the covariate period, d 22 of each interval within the treatment period, and d 8 of the recovery period. Average DMI for the experiment was 7.04 ± 0.27 kg. Methane emissions were reduced by 59.2% when NOP was used (9.16 vs. 22.46 g/kg DMI; < 0.01). Total VFA concentrations were not affected ( = 0.12); however, molar proportion of acetate was reduced and that for propionate increased when NOP was added ( < 0.01), which reduced the acetate to propionate ratio (3.0 vs. 4.0; < 0.01). The total copy number of the 16S rRNA gene of total bacteria was not affected ( = 0.50) by NOP, but the copy number of the 16S rRNA gene of methanogens was reduced ( < 0.01) and the copy number of the 18S rRNA gene of protozoa was increased ( = 0.03). The residual effect of NOP for most of the variables studied was not observed or was minimal during the recovery period. These results demonstrated that the addition of NOP to a diet for beef cattle caused a sustained decrease of methanogenesis, with no sign of adaptation, and that these effects were reversed once NOP addition was discontinued.
    Full-text · Article · Apr 2015 · Journal of Animal Science
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    • "The production of H 2 is expected to be minimal for the Control treatment and was not considered in the calculation. The metabolic hydrogen for H 2 synthesis during the treatment period was estimated based on CH 4 reduction rates, which were calculated from CH 4 production in respiration chambers as proposed by Mitsumori et al. (2012). "
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    ABSTRACT: Abstract Text: The objective was to evaluate whether long-term supplementation of diets with 3-nitrooxypropanol (NOP), a synthetic compound proven to reduce enteric CH4 emissions in short-term studies, results in a sustained reduction in enteric CH4 emissions in beef cattle. Eight ruminally cannulated heifers (637 ± 16.2 kg of BW) were used in a completely randomized design with 2 treatments: Control (0 g/d of NOP) and NOP (2 g/d of NOP). Treatments were mixed by hand into the TMR (60% forage, DM basis) at feeding time. Feed offered was restricted to 65% of ad libitum DM intake (DMI; maintenance energy intake) to avoid excessive growth. Duration of the experiment was 146 d, including an initial covariate period without NOP supplementation (18 d), 4 periods with NOP supplementation (28 d each), and a final recovery period without NOP supplementation (16 d). Methane was measured at the end of each period for 3 d using metabolic chambers. Volatile fatty acid (VFA) concentration and microbial populations were measured using rumen samples collected 0, 3 and 6 h after feeding. Data were analysed using the PROC MIXED procedure of SAS. Average DMI for the experiment was 7.0 ± 0.2 kg. Methane intensity was reduced by 60% when NOP was supplemented (22.6 vs 8.9 g/kg DMI; P < 0.01) with no signs of adaptation (period × treatment, P = 0.2). Total VFA concentrations were not affected (P = 0.12); however, acetate concentration was reduced and propionate concentration increased when NOP was supplemented (P < 0.01), which led to a reduction in the acetate to propionate ratio (3.9 vs 2.9; P < 0.01). NOP had no effect on the copy number of the 16S rRNA gene of total bacteria (P = 0.5) but the copy numbers of the 16S rRNA gene of methanogens (P < 0.01) were reduced and copy numbers of the 18S rRNA gene of protozoa (P = 0.03) were increased. All effects of NOP observed during the measurement periods were absent during the recovery period when supplementation was discontinued. These results showed that reduction of CH4 production in ruminants is sustained with long-term dietary supplementation of NOP. Keywords: 3-nitrooxypropanol, beef cattle, methane
    Full-text · Conference Paper · Jul 2014
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