Attempted induction of reductive acetogenesis into the rumen fermentation in vitro

Demeyer, D.; Fiedler, D.; Graeve, K. de

doi:10.1051/rnd:19960301

Cited by 25 publications

(14 citation statements)

References 10 publications

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“…The in vitro model used in the present study was similar to those in other studies examining rumen contents from cattle and sheep, in which an excess of fermentable carbohydrate will also cause toxicity and acidosis (2,13). Indeed, the bacterial flora of the equine cecum shows many similarities with that of the bovine rumen (26,27).…”

Section: Soc)supporting

confidence: 66%

Identification of Equine Cecal Bacteria Producing Amines in an In Vitro Model of Carbohydrate Overload

Bailey¹,

Baillon²,

Rycroft

et al. 2003

Appl Environ Microbiol

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Acute laminitis has been associated with the overgrowth of gram-positive bacteria within the equine hindgut, causing the release of factor(s) leading to ischemia-reperfusion of the digits. The products of fermentation which trigger acute laminitis are, as yet, unknown; however, vasoactive amines are possible candidates. The objectives of this study were to use an in vitro model of carbohydrate overload to study the change in populations of cecal streptococci and lactobacilli and to establish whether certain species of these bacteria were capable of producing vasoactive amines from amino acids. Cecal contents from 10 horses were divided into aliquots and incubated anaerobically with either corn starch or inulin (fructan; both at 1 g/100 ml). Samples were taken at 6-h intervals over a 24-h period for enumeration of streptococci, lactobacilli, and gram-negative anaerobes by a dilution method onto standard selective growth media. The effects of the antibiotic virginiamycin (1 mg/100 ml) and calcium hydrogen phosphate (CaHPO 4 ; 0.3 g/100 ml) were also examined. Fermentation of excess carbohydrate was associated with increases in numbers of streptococci and lactobacilli (2-to 3.5-log unit increases; inhibited by virginiamycin) but numbers of gram-negative anaerobes were not significantly affected. A screening agar technique followed by 16S rRNA gene sequence analysis enabled the identification of 26 different bacterial strains capable of producing one or more vasoactive amines. These included members of the species Streptococcus bovis and five different Lactobacillus spp. These data suggest that certain bacteria, whose overgrowth is associated with carbohydrate fermentation, are capable of producing vasoactive amines which may play a role in the pathogenesis of acute laminitis.Fermentation of carbohydrate in the hindgut has been recognized as one of the primary events associated with acute laminitis in the horse (14). The ability of the equine small intestine to digest starch may be overwhelmed if starch is present in excess (Ͼ0.4% body weight [35]), leading to its metabolism by cecal and colonic bacteria and the production of lactic acid. Fructans, the oligosaccharides present in grass which act as the storage form of carbohydrate, do not appear to be digested by the small intestine (21) and so are also substrates for fermentative bacteria. The variation of fructan levels in grasses under different climatic conditions has been suggested to account for the seasonal incidence of acute laminitis (A. C. Longland, A. J. Cairns, and M. O. Humphreys, Proc. 16th Equine Nutr. Physiol. Soc., p. 258-259, 1999).Gram-positive bacteria have been implicated in the pathogenesis of laminitis in the carbohydrate overload model since they have been shown to overgrow in the cecum of horses given corn starch by stomach tube (16). This overgrowth, particularly of streptococci and lactobacilli, was associated with lactic acid accumulation and the death of gram-negative bacteria leading to endotoxin release, both of which were postulated t...

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Section: Soc)supporting

confidence: 66%

Identification of Equine Cecal Bacteria Producing Amines in an In Vitro Model of Carbohydrate Overload

Bailey¹,

Baillon²,

Rycroft

et al. 2003

Appl Environ Microbiol

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“…Inoculation of methanogens in these gnotobiotic animals induced a drop in the concentration of acetogens and a quasi-complete use of H 2 since free hydrogen disappeared. This means that acetogens and methanogens compete for H 2 use, and that methanogens always derive advantage from this competition as confirmed by Demeyer et al [28], Le Van et al [73] and Lopez et al [75].…”

Section: Source Of C and Pattern Of Fermentationmentioning

confidence: 57%

Methane production by ruminants: its contribution to global warming

Moss

Jouany

Newbold³

2000

Ann. Zootech.

1,117

915

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-The aim of this paper is to review the role of methane in the global warming scenario and to examine the contribution to atmospheric methane made by enteric fermentation, mainly by ruminants. Agricultural emissions of methane in the EU-15 have recently been estimated at 10.2 million tonnes per year and represent the greatest source. Of these, approximately two-thirds come from enteric fermentation and one-third from livestock manure. Fermentation of feeds in the rumen is the largest source of methane from enteric fermentation and this paper considers in detail the reasons for, and the consequences of, the fact that the molar percentage of the different volatile fatty acids produced during fermentation influences the production of methane in the rumen. Acetate and butyrate promote methane production while propionate formation can be considered as a competitive pathway for hydrogen use in the rumen. The many alternative approaches to reducing methane are considered, both in terms of reduction per animal and reduction per unit of animal product. It was concluded that the most promising areas for future research for reducing methanogenesis are the development of new products/delivery systems for anti-methanogenic compounds or alternative electron acceptors in the rumen and reduction in protozoal numbers in the rumen. It is also stressed that the reason ruminants are so important to mankind is that much of the world's biomass is rich in fibre. They can convert this into high quality protein sources (i.e. meat and milk) for human consumption and this will need to be balanced against the concomitant production of methane. methane / ruminants / global warning / reduction strategies Résumé -Production de méthane par les ruminants : sa contribution au réchauffement de la planète. Cet article examine le rôle du méthane dans le processus de réchauffement de la planète et évalue la contribution au méthane atmosphérique des gaz d'origine digestive issus principalement des ruminants. Les émissions annuelles de méthane d'origine agricole dans l'Europe des quinze ont été estimées récemment à 10,2 millions de tonnes et représentent la principale source des entrées Ann. Zootech. 49 (2000) 231-253 231 © INRA, EDP Sciences

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“…Hydrogen recoveries for the ex situ and in vitro assays of both rumen and cecum inocula (total contents without substrate and strained fluids with substrate) were calculated as described by Demeyer et al (29).…”

Section: Microbial Diversity Analysis By Pcr-dggementioning

confidence: 99%

Methanogens and Methanogenesis in the Rumens and Ceca of Lambs Fed Two Different High-Grain-Content Diets

Popova

Morgavi

Martin

2013

Appl Environ Microbiol

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The amount and nature of dietary starch are known to influence the extent and site of feed digestion in ruminants. However, how starch degradability may affect methanogenesis and methanogens along the ruminant's digestive tract is poorly understood. This study examined the diversity and metabolic activity of methanogens in the rumen and cecum of lambs receiving wheat or corn high-graincontent diets. Methane production in vivo and ex situ was also monitored. In vivo daily methane emissions (CH 4 g/day) were 36% (P < 0.05) lower in corn-fed lambs than in wheat-fed lambs. Ex situ methane production (mol/h) was 4-fold higher for ruminal contents than for cecal contents (P < 0.01), while methanogens were 10-fold higher in the rumen than in the cecum (mcrA copy numbers; P < 0.01). Clone library analysis indicated that Methanobrevibacter was the dominant genus in both sites. Diet induced changes at the species level, as the Methanobrevibacter millerae-M. gottschalkii-M. smithii clade represented 78% of the sequences from the rumen of wheat-fed lambs and just about 52% of the sequences from the rumen of the corn-fed lambs. Diet did not affect mcrA expression in the rumen. In the cecum, however, expression was 4-fold and 2-fold lower than in the rumen for wheat-and corn-fed lambs, respectively. Though we had no direct evidence for compensation of reduced rumen methane production with higher cecum methanogenesis, the ecology of methanogens in the cecum should be better considered.

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Attempted induction of reductive acetogenesis into the rumen fermentation in vitro

Cited by 25 publications

References 10 publications

Identification of Equine Cecal Bacteria Producing Amines in an In Vitro Model of Carbohydrate Overload

Identification of Equine Cecal Bacteria Producing Amines in an In Vitro Model of Carbohydrate Overload

Methane production by ruminants: its contribution to global warming

Methanogens and Methanogenesis in the Rumens and Ceca of Lambs Fed Two Different High-Grain-Content Diets

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