Members of the domain Archaea contribute about 0.3 to 3.3% of the microbial small subunit (16S and 18S) rRNA in the rumen (22, 39, 60). Archaea have a range of different metabolisms and are found in many habitats (6), but those known to exist in the rumen are strictly anaerobic methanogens. Yanagita et al. (59) observed that 2.8 to 4.0% of ruminal microorganisms displayed autofluorescence chara...

Sheep fed a hay-concentrate diet were adapted to pectin administration and ruminal infusion of methanol. Both treatments resulted in a strong increase in the rate of methanogenesis from methanol. Quantitative data show that methanol was exclusively converted into methane. Treatments did not influence ruminal volatile fatty acid percentages.

Rumen microbiota are essential for maintaining digestive and metabolic functions, producing methane as a byproduct. Dairy heifers produce large amounts of methane based on fermentation of digested organic matter, with adverse consequences for feed efficiency and the environment. It is therefore important to understand the influence of host age on the relationship between microbiota and methane ...

The Ruminant Nutrition Symposium titled "Acidosis: New insights into the persistent problem" was held at the Joint Annual Meeting of the American Dairy Science Association, American Society of Animal Science, Poultry Science Association, Asociación Mexicana de Producción Animal, Western Section-ASAS, and the Canadian Society of Animal Science in Denver, Colorado, July 11 to 15, 2010. The object...

OBJECTIVE Manipulating the fermentation to improve the performance of the ruminant has attracted the attention of both farmers and animal scientists. Propionate salt supplementation in the diet could disturb the concentration of propionate and total volatile fatty acids in the rumen. This study was conducted to evaluate the effect of calcium propionate supplementation on the ruminal bacterial c...

This study investigated the effects of disodium fumarate (DF) on methane emission, ruminal fermentation and microbial abundance in goats under different forage (F) : concentrate (C) ratios and fed according to maintenance requirements. Four ruminally fistulated, castrated male goats were used in a 4 × 4 Latin square design with a 2 × 2 factorial arrangement of treatments and the main factors be...

Ruminal inoculum enriched with particle-associated microorganisms was collected from rumen cannulated Santa Inês wethers grazing tropical grass pasture and a supplement based on ground corn and soybean before feeding and used to evaluate effects of some commercial essential oils (EO) on ruminal fermentation and methane emission in vitro. The investigated EOs were orange EO (Citrus sinensis, CrS...

We investigated the effect of phytosterols on rumen fermentation in vitro using gas syringes as incubators. Phytosterols were dissolved in ethyl acetate (8.3%) and added at various concentrations to the common diet in rumen fluid. In vitro gas production (GP) was recorded after 3, 6, 12, 18, and 24 h incubation. Incubation was stopped at 6, 12, and 24 h and the inoculants were then tested for p...

This study was conducted to investigate the effect of soybean meal (SM) and soluble starch (SS) on biogenic amine production and microbial diversity using in vitro ruminal fermentation. Treatments comprised of incubation of 2 g of mixture (expressed as 10 parts) containing different ratios of SM to SS as: 0:0, 10:0, 7:3, 5:5, 3:7, or 0:10. In vitro ruminal fermentation parameters were determine...

Introduction T h e first axiom of ruminology appears to be: ‘The rumen is a strictly anaerobic system’ (Hungate, 1966) but before we accept this we should examine the evidence for and against this assertion. Probably the strongest evidence for anaerobiosis comes from the studies of the reactions in the rumen, from the stoichiometries observed and from the low oxidation-reduction potential obtai...