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In vitro lactate metabolism by ruminal ingesta
- Source :
- Applied microbiology. 16(5)
- Publication Year :
- 1968
-
Abstract
- Ruminal ingesta (300 ml) obtained from a fistulated cow fed alfalfa hay (H), 3.6 kg of grain mixture with corn silage fed ad libitum (S), 2.5:1 grain-alfalfa hay mixture (G), or a 2.5:1 grain-alfalfa hay mixture providing 545 g of sodium and calcium lactate daily (L) were incubated for 8 hr with nonpolymerized sodium lactate or 17% polymerized lactic acid neutralized to p H 6.7. Polymerization had no effect on the rate of lactate utilization. The initial rates of lactate metabolism for the H, G, S, and L ingesta were 0.72, 0.95, 1.8, and 3.4 meq per 100 ml of rumen fluid per hr, respectively. Lactate- 2 - 14 C was incubated for 4 hr with each type of ruminal ingesta. Of the label recovered in the volatile fatty acids (VFA), 74.1, 61.2, 49.3, and 38.9% was recovered in acetate, and 9.4, 19.8, 23.3, and 51.9% was recovered in propionate with H, G, S, and L ingesta, respectively. The balance of label was distributed between butyrate and valerate. The titratable VFA did not follow this pattern of production. With the hay ingesta, lactate metabolism resulted in a net loss of acetate and a large increase in butyrate. Little propionate was produced. The G, S, and L ingesta metabolized lactate to yield progressively more propionate and less butyrate. Evidence was gathered to suggest that acetate was the primary end product of lactate metabolism but that oxidation of lactate to pyruvate dictated the synthesis of butyrate from acetate to maintain an oxidation-reduction balance. It was noted that acetate and butyrate production from lactate was p H-dependent, with acetate production maximal at p H 7.4 and butyrate at 6.2. Propionate production was largely unaffected within this p H range.
- Subjects :
- Rumen
Polymers
Butyrate
Biology
Acetates
General Biochemistry, Genetics and Molecular Biology
chemistry.chemical_compound
Animal science
Sodium lactate
Animals
General Pharmacology, Toxicology and Pharmaceutics
chemistry.chemical_classification
Carbon Isotopes
General Immunology and Microbiology
Fatty Acids
General Medicine
Metabolism
Articles
Animal Feed
Lactic acid
chemistry
Biochemistry
Propionate
Hay
Lactates
Cattle
Pyruvic acid
Propionates
Subjects
Details
- ISSN :
- 00036919
- Volume :
- 16
- Issue :
- 5
- Database :
- OpenAIRE
- Journal :
- Applied microbiology
- Accession number :
- edsair.doi.dedup.....bd82e6e31246dcbab074eec536e93566