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Volatile fatty acid and alcohol determination in digestive contents, silage juices, bacterial cultures and anaerobic fermentor contents [microbial fermentation, biological liquids, analytic method using gas-liquid chromatography].

About: This article is published in Sciences Des Aliments.The article was published on 1982-01-01 and is currently open access. It has received 112 citations till now. The article focuses on the topics: Fermentation & Silage.
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Journal ArticleDOI
TL;DR: A new type of system to simulate conditions in the large intestine that combines removal of metabolites and water with peristaltic mixing to obtain and handle physiological concentrations of microorganisms, dry matter and microbial metabolites is introduced.
Abstract: This paper introduces a new type of system to simulate conditions in the large intestine. This system combines removal of metabolites and water with peristaltic mixing to obtain and handle physiological concentrations of microorganisms, dry matter and microbial metabolites. The system has been designed to be complementary to the dynamic multi-compartmental system that simulates conditions in the stomach and small intestine described by Minekus et al. [Minekus M, Marteau P, Havenaar R, Huis in't Veld JHJ (1995) ATLA 23:197-209]. High densities of microorganisms, comparable to those found in the colon in vivo, were achieved by absorption of water and dialysis of metabolites through hollow-fibre membranes inside the reactor compartments. The dense chyme was mixed and transported by peristaltic movements. The potential of the system as a tool to study fermentation was demonstrated in experiments with pectin, fructo-oligosaccharide, lactulose and lactitol as substrates. Parameters such as total acid production and short-chain fatty acid (SCFA) patterns were determined with time to characterize the fermentation. The stability of the microflora in the system was tested after inoculation with fresh fecal samples and after inoculation with a microflora that was maintained in a fermenter. Both approaches resulted in total anaerobic bacterial counts higher than 1010 colony-forming units/ml with physiological levels of Bifidobacterium, Lactobacillus, Enterobacteriaceae and Clostridium. The dry matter content was approximately 10%, while the total SCFA concentration was maintained at physiological concentrations with similar molar ratios for acetic acid, propionic acid and butyric acid as measured in vivo.

426 citations


Cites methods from "Volatile fatty acid and alcohol det..."

  • ...Samples for SCFA analysis were mixed with 10% phosphoric acid and kept at )20 °C for gas chromatographic analysis according to the method of Jouany (1982)....

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Journal ArticleDOI
Xiao-dong Pan1, Fen-qin Chen1, Tian-xing Wu1, Hong-gang Tang1, Zhan-yu Zhao1 
TL;DR: After 14 d treatment, SCFAs and lactate in mice cecum were significantly increased (P<0.05) by intake of oligosaccharides, especially FOS and GOS, therefore, providing these oligosACcharides as ingredients in nutritional formulas may benefit the gastrointestinal tract.
Abstract: The purpose of this study was to clarify effects of selected oligosaccharides on concentrations of cecal short-chain fatty acids (SCFAs), total large bowel wet weight and wall weight, and cecal microbiota levels in mice. Mice were respectively given gavage of selected fructooligosaccharides (FOS), galactooligosaccharides (GOS), mannanoligosaccharides (MOS), and chitooligosaccharides (COS) [1000 mg/(kg body weight·d)]. Control group was given physiological saline solution. After 14 d treatment, SCFAs and lactate in mice cecum were significantly increased (P<0.05) by intake of oligosaccharides, especially FOS and GOS. Thus, providing these oligosaccharides as ingredients in nutritional formulas may benefit the gastrointestinal tract.

153 citations


Cites methods from "Volatile fatty acid and alcohol det..."

  • ...SCFAs were analyzed by gas chromatography according to Jouany (1982) on supernatant of thawed samples centrifuged at 8000×g for 10 min....

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Journal ArticleDOI
TL;DR: Methanogens appeared in the rumen of 30-h-old lambs, and as they developed there was a proportional decrease in the numbers of acetogens, indicating a competition for hydrogen between these two groups.
Abstract: The development of hydrogenotrophic bacteria in the rumen of lambs was investigated by culture and labeling experiments. 14CO2 and 13CO2 incorporation by the rumen microflora of a 24-h-old lamb showed that while there was no labeled methane, double-labeled acetate was formed indicating the presence of hydrogen-dependent acetogenesis. In vitro counts from rumen fluid of 20-h-old lambs confirmed an extensive colonization of acetogenic bacteria while methanogens were absent. Methanogens appeared in the rumen of 30-h-old lambs, and as they developed there was a proportional decrease in the numbers of acetogens, indicating a competition for hydrogen between these two groups. Hydrogen-utilizing sulfate-reducing bacteria, which were established by the 3rd day after birth, did not seem to be affected by this competition.

122 citations

Journal ArticleDOI
TL;DR: Thirteen plant extracts, selected for their high flavonoid content, were screened on their action on fermentation and protozoa numbers in 1 l dual outflow fermenters supplied with a 50:50 orchard grass hay+barley diet and found that Protozoa numbers were little affected by plant extracts.

105 citations

Journal ArticleDOI
TL;DR: Findings provide the first evidence from animal studies that reductive acetogens can sustain a functional rumen and replace methanogens as a sink for H2 in the rumen.
Abstract: The aim of this work was to determine whether reductive acetogenesis can provide an alternative to methanogenesis in the rumen. Gnotobiotic lambs were inoculated with a functional rumen microbiota lacking methanogens and reared to maturity on a fibrous diet. Lambs with a methanogen-free rumen grew well, and the feed intake and ruminal volatile fatty acid concentrations for lambs lacking ruminal methanogens were lower but not markedly dissimilar from those for conventional lambs reared on the same diet. A high population density (107 to 108 cells g−1) of ruminal acetogens slowly developed in methanogen-free lambs. Sulfate- and fumarate-reducing bacteria were present, but their population densities were highly variable. In methanogen-free lambs, the hydrogen capture from fermentation was low (28 to 46%) in comparison with that in lambs containing ruminal methanogens (>90%). Reductive acetogenesis was not a significant part of ruminal fermentation in conventional lambs but contributed 21 to 25% to the fermentation in methanogen-free meroxenic animals. Ruminal H2 utilization was lower in lambs lacking ruminal methanogens, but when a methanogen-free lamb was inoculated with a methanogen, the ruminal H2 utilization was similar to that in conventional lambs. H2 utilization in lambs containing a normal ruminal microflora was age dependent and increased with the animal age. The animal age effect was less marked in lambs lacking ruminal methanogens. Addition of fumarate to rumen contents from methanogen-free lambs increased H2 utilization. These findings provide the first evidence from animal studies that reductive acetogens can sustain a functional rumen and replace methanogens as a sink for H2 in the rumen.

104 citations