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Indigenous bacteria and bacterial metabolic products in the gastrointestinal tract of broiler chickens.

https://arctichealth.org/en/permalink/ahliterature160205
Source
Arch Anim Nutr. 2007 Oct;61(5):319-35
Publication Type
Article
Date
Oct-2007
Author
Habib Ur Rehman
Wilfried Vahjen
Wageha A Awad
Jürgen Zentek
Author Affiliation
Institute of Nutrition, Department of Veterinary Public Health and Food Science, University of Veterinary Medicine, Vienna, Austria.
Source
Arch Anim Nutr. 2007 Oct;61(5):319-35
Date
Oct-2007
Language
English
Publication Type
Article
Keywords
Age Factors
Animal Feed
Animal Nutritional Physiological Phenomena - physiology
Animals
Bacteria - growth & development - metabolism
Chickens - metabolism - microbiology
Consumer Product Safety
Fatty Acids, Volatile - biosynthesis
Fermentation
Gastrointestinal Tract - microbiology
Humans
Abstract
The gastrointestinal tract is a dynamic ecosystem containing a complex microbial community. In this paper, the indigenous intestinal bacteria and the microbial fermentation profile particularly short chain fatty acids (SCFA), lactate, and ammonia concentrations are reviewed. The intestinal bacterial composition changes with age. The bacterial density of the small intestine increases with age and comprises of lactobacilli, streptococci, enterobacteria, fusobacteria and eubacteria. Strict anaerobes (anaerobic gram-positive cocci, Eubacterium spp., Clostridium spp., Lactobacillus spp., Fusobacterium spp. and Bacteroides) are predominating caecal bacteria in young broilers. Data from culture-based studies showed that bifidobacteria could not be isolated from young birds, but were recovered from four-week-old broilers. Caecal lactobacilli accounted for 1.5-24% of the caecal bacteria. Gene sequencing of caecal DNA extracts showed that the majority of bacteria belonged to Clostridiaceae. Intestinal bacterial community is influenced by the dietary ingredients, nutrient levels and physical structure of feed. SCFA and other metabolic products are affected by diet formulation and age. Additional studies are required to know the bacterial metabolic activities together with the community analysis of the intestinal bacteria. Feed composition and processing have great potential to influence the activities of intestinal bacteria towards a desired direction in order to support animal health, well-being and microbial safety of broiler meat.
PubMed ID
18030916 View in PubMed
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Thermophilic anaerobes in Arctic marine sediments induced to mineralize complex organic matter at high temperature.

https://arctichealth.org/en/permalink/ahliterature97862
Source
Environ Microbiol. 2010 Apr;12(4):1089-104
Publication Type
Article
Date
Apr-2010
Author
Casey Hubert
Carol Arnosti
Volker Brüchert
Alexander Loy
Verona Vandieken
Bo Barker Jørgensen
Author Affiliation
Department of Biogeochemistry, Max Planck Institute for Marine Microbiology, Bremen, Germany. casey.hubert@newcastle.ac.uk
Source
Environ Microbiol. 2010 Apr;12(4):1089-104
Date
Apr-2010
Language
English
Publication Type
Article
Keywords
Arctic Regions
Bacteria, Anaerobic - metabolism
Desulfotomaculum - genetics - metabolism
Fatty Acids, Volatile - biosynthesis
Fermentation
Food chain
Geologic Sediments - microbiology
Hot Temperature
Hydrolysis
Molecular Sequence Data
Phylogeny
Polysaccharides - metabolism
Spirulina - metabolism
Sulfates - metabolism
Abstract
Marine sediments harbour diverse populations of dormant thermophilic bacterial spores that become active in sediment incubation experiments at much higher than in situ temperature. This response was investigated in the presence of natural complex organic matter in sediments of two Arctic fjords, as well as with the addition of freeze-dried Spirulina or individual high-molecular-weight polysaccharides. During 50 degrees C incubation experiments, Arctic thermophiles catalysed extensive mineralization of the organic matter via extracellular enzymatic hydrolysis, fermentation and sulfate reduction. This high temperature-induced food chain mirrors sediment microbial processes occurring at cold in situ temperatures (near 0 degrees C), yet it is catalysed by a completely different set of microorganisms. Using sulfate reduction rates (SRR) as a proxy for organic matter mineralization showed that differences in organic matter reactivity determined the extent of the thermophilic response. Fjord sediments with higher in situ SRR also supported higher SRR at 50 degrees C. Amendment with Spirulina significantly increased volatile fatty acids production and SRR relative to unamended sediment in 50 degrees C incubations. Spirulina amendment also revealed temporally distinct sulfate reduction phases, consistent with 16S rRNA clone library detection of multiple thermophilic Desulfotomaculum spp. enriched at 50 degrees C. Incubations with four different fluorescently labelled polysaccharides at 4 degrees C and 50 degrees C showed that the thermophilic population in Arctic sediments produce a different suite of polymer-hydrolysing enzymes than those used in situ by the cold-adapted microbial community. Over time, dormant marine microorganisms like these are buried in marine sediments and might eventually encounter warmer conditions that favour their activation. Distinct enzymatic capacities for organic polymer degradation could allow specific heterotrophic populations like these to play a role in sustaining microbial metabolism in the deep, warm, marine biosphere.
PubMed ID
20192966 View in PubMed
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