Twenty male crossbred Texel lambs were used in a 2 × 2 factorial design experiment to assess the effect of dietary addition of nitrate (2.6% of dry matter) and sulfate (2.6% of dry matter) on enteric methane emissions, rumen volatile fatty acid concentrations, rumen microbial composition, and the occurrence of methemoglobinemia. Lambs were gradually introduced to nitrate and sulfate in a corn silage-based diet over a period of 4 wk, and methane production was subsequently determined in respiration chambers. Diets were given at 95% of the lowest ad libitum intake observed within one block in the week before methane yield was measured to ensure equal feed intake of animals between treatments. All diets were formulated to be isonitrogenous. Methane production decreased with both supplements (nitrate: -32%, sulfate: -16%, and nitrate+sulfate: -47% relative to control). The decrease in methane production due to nitrate feeding was most pronounced in the period immediately after feeding, whereas the decrease in methane yield due to sulfate feeding was observed during the entire day. Methane-suppressing effects of nitrate and sulfate were independent and additive. The highest methemoglobin value observed in the blood of the nitrate-fed animals was 7% of hemoglobin. When nitrate was fed in combination with sulfate, methemoglobin remained below the detection limit of 2% of hemoglobin. Dietary nitrate decreased heat production (-7%), whereas supplementation with sulfate increased heat production (+3%). Feeding nitrate or sulfate had no effects on volatile fatty acid concentrations in rumen fluid samples taken 24h after feeding, except for the molar proportion of branched-chain volatile fatty acids, which was higher when sulfate was fed and lower when nitrate was fed, but not different when both products were included in the diet. The total number of rumen bacteria increased as a result of sulfate inclusion in the diet. The number of methanogens was reduced when nitrate was fed. Enhanced levels of sulfate in the diet increased the number of sulfate-reducing bacteria. The number of protozoa was not affected by nitrate or sulfate addition. Supplementation of a diet with nitrate and sulfate is an effective means for mitigating enteric methane emissions from sheep.
"Inorganic electron acceptors Nitrate , sulfate , arsenate Herbel et al . ( 2002 ) , Van Zijderveld et al . ( 2010 ) Hydroxyaromatic compounds Phloroglucinol Tsai and Jones ( 1975 ) , Patel et al . ( 1981 ) Flavonoids Rutin , quercitin , naringin , hesperidin Simpson et al . ( 1969 ) Plant toxins Allyl cyanide Duncan and Milne ( 1992 ) Fluoroacetate Camboim et al . ( 2012 ) Mimosine Jones and Megarrity ( 1986 ) Allison et al . ( 1992 ) Nitro - 1 - p"
[Show abstract][Hide abstract] ABSTRACT: The ruminal microbial community is remarkably diverse, containing 100s of different bacterial and archaeal species, plus many species of fungi and protozoa. Molecular studies have identified a "core microbiome" dominated by phyla Firmicutes and Bacteroidetes, but also containing many other taxa. The rumen provides an ideal laboratory for studies on microbial ecology and the demonstration of ecological principles. In particular, the microbial community demonstrates both redundancy (overlap of function among multiple species) and resilience (resistance to, and capacity to recover from, perturbation). These twin properties provide remarkable stability that maintains digestive function for the host across a range of feeding and management conditions, but they also provide a challenge to engineering the rumen for improved function (e.g., improved fiber utilization or decreased methane production). Direct ruminal dosing or feeding of probiotic strains often fails to establish the added strains, due to intensive competition and amensalism from the indigenous residents that are well-adapted to the historical conditions within each rumen. Known exceptions include introduced strains that can fill otherwise unoccupied niches, as in the case of specialist bacteria that degrade phytotoxins such as mimosine or fluoroacetate. An additional complicating factor in manipulating the ruminal fermentation is the individuality or host specificity of the microbiota, in which individual animals contain a particular community whose species composition is capable of reconstituting itself, even following a near-total exchange of ruminal contents from another herd mate maintained on the same diet. Elucidation of the interactions between the microbial community and the individual host that establish and maintain this specificity may provide insights into why individual hosts vary in production metrics (e.g., feed efficiency or milk fat synthesis), and how to improve herd performance.
Frontiers in Microbiology 04/2015; 6:296. DOI:10.3389/fmicb.2015.00296 · 3.99 Impact Factor
"To a lesser degree, PUFA can reduce H 2 availability in the rumen by consuming H 2 during bio hydrogenation (Czerkawski, 1986). Nitrate modifies H 2 consumption by reducing the number of methano gens (Van Zijderveld et al., 2010) and by acting as a H 2 sink (Lewis, 1951). As these dietary treatments share different mecha nisms of action, we hypothesized that their combina tion would have an additive effect that leads to less net methanogenesis than when they are individually fed. "
[Show abstract][Hide abstract] ABSTRACT: The objective of this study was to test the effect of linseed oil and nitrate fed alone or in combination on methane (CH4) emissions and diet digestibility in cows. The experiment was conducted as a 2 × 2 factorial design using 4 multiparous nonlactating Holstein cows (initial BW 656 ± 31 kg). Each experimental period lasted 5 wk, with measures performed in the final 3 wk (wk 3 to 5). Diets given on a DM basis were 1) control (CON; 50% natural grassland hay and 50% concentrate), 2) CON with 4% linseed oil (LIN), 3) CON with 3% calcium nitrate (NIT), and 4) CON with 4% linseed oil plus 3% calcium nitrate (LIN+NIT). Diets were offered twice daily and were formulated to deliver similar amounts (DM basis) of CP (12.2%), starch (25.5%), and NDF (39.5%). Feed offer was restricted to 90% of voluntary intake (12.4 kg DMI/d). Total tract digestibility and N balance were determined from total feces and urine collected separately for 6 d during wk 4. Daily CH4 emissions were quantified using open chambers for 4 d during wk 5. Rumen fermentation and microbial parameters were analyzed from samples taken before and 3 h after the morning feeding. Rumen concentrations of dissolved hydrogen (H2) were measured continuously up to 6 h after feeding using a H2 sensor. Compared with the CON diet linseed oil and nitrate decreased (P < 0.01) CH4 emissions (g/kg DMI) by 17 and 22%, respectively, when fed alone and by 32% when combined. The LIN diet reduced CH4 production throughout the day, increased (P = 0.02) propionate proportion, and decreased (P = 0.03) ruminal protozoa concentration compared with CON diet. The NIT diet strongly reduced CH4 production 3 h after feeding, with a simultaneous increase in rumen dissolved H2 concentration, suggesting that nitrate does not act only as an electron acceptor. As a combined effect, linseed plus nitrate also increased H2 concentrations in the rumen. Diets had no effect (P > 0.05) on total tract digestibility of nutrients, except linseed oil, which tended to reduce (P < 0.10) fiber digestibility. Nitrogen balance (% of N intake) was positive for all diets but retention was less (P = 0.03) with linseed oil. This study demonstrates an additive effect between nitrate and linseed oil for reducing methanogenesis in cows without altering diet digestibility.
"Fumarate increased total VFA concentration, which might be attributed to conversion of fumarate to propionate , which has been noted in several studies (Bayaru et al., 2001; Beauchemin and McGinn, 2006; Zhou et al., 2012) However, McGinn et al. (2004) fed 10.6 g/kg of DM intake of fumaric acid to cattle (approximately 15 mM) and reported no effect on total VFA concentration, propionate proportions , or methane emissions. Corroborating with this study, higher concentrations of total VFA concentrations in nitrate treatments (Nolan et al., 2010; Van Zijderveld et al., 2010) were also noted in other studies. Tree leaves-containing diets had greater degradability than the grass-based diet, and the effect was more pronounced for high R:C (i.e. "
[Show abstract][Hide abstract] ABSTRACT: This experiment was conducted to study the effects of nitrate and fumarate on nutrient utilization, rumen fermentation and blood biochemical profile in sheep fed on tree leaves-based diet. Thirty two matured male Chokla breed of sheep (2-3 years old and 46.9 +/- 0.95 kg average body weight) were equally distributed in a randomized block design in four groups with similar average age and mean body weight All groups were fed diets containing roughage and concentrate in a 70:30 ratio. Control group
Data provided are for informational purposes only. Although carefully collected, accuracy cannot be guaranteed. The impact factor represents a rough estimation of the journal's impact factor and does not reflect the actual current impact factor. Publisher conditions are provided by RoMEO. Differing provisions from the publisher's actual policy or licence agreement may be applicable.