Production of volatile fatty acids in the sheep caecum

1969 ◽  
Vol 20 (3) ◽  
pp. 491 ◽  
Author(s):  
GJ Faichney
Keyword(s):  
Fatty Acids ◽  
Steady State ◽  
Fatty Acid ◽  
Production Rate ◽  
Energy Intake ◽  
Isotope Dilution ◽  
Volatile Fatty Acids ◽  
Specific Activity ◽  
Total Production ◽  
Digestible Energy

Acetic, propionic, and butyric acids labelled with 14C were infused into the caecum of continuously fed sheep. The specific activity of the volatile fatty acids (VFA) in the caecum was determined at intervals during the infusion. The production rate was calculated by isotope dilution from the results of those experiments in which steady state conditions were obtained. Substantial interconversions occurred between the fatty acid fractions. The total production of VFA was about 440 mmoles/day, equivalent to 125 kcal/day or 5.3% of the animal's digestible energy intake.

Rates of production of volatile fatty acids in the rumen. V. Evaluation of fodders in terms of volatile fatty acid produced in the rumen of the sheep

1967 ◽  
Vol 18 (4) ◽  
pp. 625 ◽  
Author(s):  
FV Gray ◽  
RA Weller ◽  
AF Pilgrim ◽  
GB Jones
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Volatile Fatty Acid ◽  
Volatile Fatty Acids ◽  
Night Time ◽  
Digestible Energy ◽  
Significant Difference ◽  
Freely Moving

l(a). Volatile fatty acid (VFA) production (moles/12 hr) by two sheep fed at 2-hourly intervals on a constant ration containing equal parts of wheaten hay and lucerne hay, showed no significant difference between the sheep or between day-time and night-time values. The precision with which production could be measured over a series of 12-hr periods is given. The quantities of VFA produced in the rumen on successive days varied considerably; the extent of this variation was similar to that occurring in the quantities of faeces passed. (b) Production remained much the same whether the sheep were fed at intervals of 1, 2, or 12 hr. (c) The energy of the VFA produced in the rumen was equivalent to about 54% of the digestible energy of the diet. 2. Similar amounts of VFA were produced from two different mixtures of wheaten hay and lucerne hay, and from lucerne hay alone. 3. A modification in the procedure for measuring VFA production was tested and found to be satisfactory. The necessary apparatus could be readily carried on the back of a freely moving sheep.

INFLUENCE OF DIETARY VOLATILE FATTY ACID MIXTURES ON PERFORMANCE AND ON FAT COMPOSITION OF GROWING PIGS

1971 ◽  
Vol 51 (1) ◽  
pp. 89-94 ◽  
Author(s):  
J. P. BOWLAND ◽  
B. A. YOUNG ◽  
L. P. MILLIGAN
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Feed Intake ◽  
Volatile Fatty Acids ◽  
Control Diet ◽  
Weight Percent ◽  
Growing Pigs ◽  
Bomb Calorimetry ◽  
Digestible Energy ◽  
Gross Energy

Two experiments were conducted to evaluate the acceptability, calculated digestible energy, influence on performance, and effect on fatty acid composition of backfat when a mixture of volatile fatty acids (VFA) or of a sodium salt of these fatty acids (Na VFA) was fed to pigs. The weight percent of the VFA mixture was 40 acetic, 40 propionic and 20 butyric acid. Adding 2 to 8% VFA or Na VFA to the diet, without adjustment for digestible energy or total protein, did not influence feed intake or rate of gain. Dietary levels of 10 or 12% VFA or Na VFA depressed daily gain. When 4% VFA or Na VFA was fed from an initial weight of 12 kg, feed intake was not altered in comparison with that of pigs fed a control diet. Rate of gain averaged 0.64 kg per day for pigs fed either VFA or Na VFA, compared with 0.60 kg for control pigs. The digestible energy values of the VFA and Na VFA, based on calculated energy conversion from 38 to 75 kg liveweight, were higher than the gross energy values of the compounds determined by oxygen bomb calorimetry, presumably because of a synergistic action of VFA with other energy sources in the diet. Carcass backfat thickness, area of loin and lean in the ham face were not significantly altered by feeding VFA or Na VFA. When pigs received up to 12% VFA or Na VFA, weight percent oleic acid in the outer backfat was increased (P < 0.05) from 49.9% in the control pigs to between 52.7 and 53.3 percent. There was no influence on backfat composition when 4% VFA or Na VFA was fed continuously.

Calculation of metabolic fluxes with anatomically separated sources of tracer and tracee

1986 ◽  
Vol 251 (6) ◽  
pp. E715-E720
Author(s):  
K. H. Norwich ◽  
D. H. Wasserman
Keyword(s):  
Steady State ◽  
Fatty Acid ◽  
Free Fatty Acid ◽  
Isotope Dilution ◽  
Specific Activity ◽  
Infusion Site ◽  
Distribution Space ◽  
Tracer Concentration ◽  
Metabolic Fluxes ◽  
Endogenous Release

Traditional calculations of metabolic fluxes using isotope dilution are based on the assumption that tracer and tracee enter the distribution space through effectively identical ports. If the tracer infusion site is not identical with the site of endogenous release of the tracee, the traditional equations for calculating rate of appearance (Ra) of a metabolite may give rise to appreciable errors due to the presence of gradients in specific activity. When tracer and tracee enter by means of anatomically disparate sites, such as may be encountered in the study of metabolite (e.g., lactate, alanine, and glycerol) or free fatty acid turnover, one must employ a modification of the traditional specific activity. This modified specific activity is obtained as the ratio of tracer concentration "near" (in the same compartment as) the source of tracee to the concentration of tracee near the source of tracer infusion. This concept is employed to derive equations for calculating metabolic turnover in both steady- and non-steady-state conditions when entry sites of tracer and tracee are dissimilar.

scholarly journals Determination of Volatile Fatty Acids in Bovine Blood by Isotope Dilution

1959 ◽  
Vol 42 (2) ◽  
pp. 358-362
Author(s):  
J.B. Holter ◽  
S. Lakshmanan ◽  
J.C. Shaw
Keyword(s):  
Fatty Acids ◽  
Isotope Dilution ◽  
Volatile Fatty Acids ◽  
Bovine Blood

Uptake and metabolism of circulating fatty acids by rat intestine

1992 ◽  
Vol 263 (6) ◽  
pp. G927-G933 ◽  
Author(s):  
C. M. Mansbach ◽  
R. F. Dowell
Keyword(s):  
Fatty Acids ◽  
Steady State ◽  
Specific Activity ◽  
Femoral Vein ◽  
Tracer Injection ◽  
Previous Hypothesis ◽  
Injection Techniques ◽  
Lymph Duct ◽  
Glyceryl Trioleate ◽  
Uptake And Metabolism

The present study was designed to investigate the uptake and metabolism of circulating fatty acids by the intestinal mucosa in rats actively absorbing glyceryl trioleate given intraduodenally to determine the plasma fatty acid contribution to mucosal triacylglycerol. Rats with duodenal, femoral vein, carotid artery, and mesenteric lymph duct cannulas were used. [3H]oleate was constantly infused into the femoral vein while glyceryl trioleate was infused into the duodenum (135 mumol/h). After 5 h of infusion, a mass and radioactive steady state existed in the plasma and mucosa. At 6 h of infusion, the plasma oleate specific activity was sixfold greater than mucosal oleate and 50 times greater than mucosal triacylglycerol oleate; 86% of the mucosal oleate disintegrations/minute were in triacylglycerol. Chylomicron triacylglycerol oleate specific activity was less than that of the mucosa. Furthermore, the percentage of mucosal triacylglycerol acyl groups composed of oleate was greater than the percentage of oleate in mucosal free fatty acids. The data indicate that fatty acids are taken up by the mucosa during active fat absorption and metabolized primarily to triacylglycerols by the mucosa. The triacylglycerols in the mucosa synthesized from circulating fatty acids are selected against as a precursor of chylomicron triacylglycerol. The results support our previous hypothesis suggesting that the mucosa has at least two pools of neutral lipid (J. Lipid Res. 23: 1009-1019, 1982) and that steady-state conditions as performed here yield different results from previous work using bolus tracer injection techniques.

scholarly journals A kinetic rationale for functional redundancy in fatty acid biosynthesis

2020 ◽  
Vol 117 (38) ◽  
pp. 23557-23564
Author(s):  
Alex Ruppe ◽  
Kathryn Mains ◽  
Jerome M. Fox
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Fatty Acid Synthase ◽  
Unsaturated Fatty Acids ◽  
Fatty Acid Biosynthesis ◽  
Average Length ◽  
Functional Redundancy ◽  
Experimental Investigations ◽  
Total Production

Cells build fatty acids with biocatalytic assembly lines in which a subset of enzymes often exhibit overlapping activities (e.g., two enzymes catalyze one or more identical reactions). Although the discrete enzymes that make up fatty acid pathways are well characterized, the importance of catalytic overlap between them is poorly understood. We developed a detailed kinetic model of the fatty acid synthase (FAS) ofEscherichia coliand paired that model with a fully reconstituted in vitro system to examine the capabilities afforded by functional redundancy in fatty acid synthesis. The model captures—and helps explain—the effects of experimental perturbations to FAS systems and provides a powerful tool for guiding experimental investigations of fatty acid assembly. Compositional analyses carried out in silico and in vitro indicate that FASs with multiple partially redundant enzymes enable tighter (i.e., more independent and/or broader range) control of distinct biochemical objectives—the total production, unsaturated fraction, and average length of fatty acids—than FASs with only a single multifunctional version of each enzyme (i.e., one enzyme with the catalytic capabilities of two partially redundant enzymes). Maximal production of unsaturated fatty acids, for example, requires a second dehydratase that is not essential for their synthesis. This work provides a kinetic, control-theoretic rationale for the inclusion of partially redundant enzymes in fatty acid pathways and supplies a valuable framework for carrying out detailed studies of FAS kinetics.

Volatile fatty acids and sulfide in pressure mains

1995 ◽  
Vol 31 (7) ◽  
pp. 169-179 ◽  
Author(s):  
T. Hvitved-Jacobsen ◽  
K. Raunkjær ◽  
P. H. Nielsen
Keyword(s):  
Fatty Acids ◽  
Organic Matter ◽  
Production Rate ◽  
Volatile Fatty Acids ◽  
Production Rates ◽  
Net Production ◽  
Toc Removal ◽  
Sulfide Production ◽  
Transformation Of Organic Matter ◽  
High Sulfide

The main objective was to study the anaerobic transformation of organic matter and sulfide production during wastewater transportation. Emphasis was on the transformation of easily biodegradable organic matter in terms of volatile fatty acids (VFA). Samples from two intercepting pressure mains located in the Northern part of Jutland, Denmark, were taken. The concentration of VFA in the wastewater varied considerably during day and night, being typically between 5 and 50 g/m3. A net production as well as a net removal of VFA was seen during transportation in the pressure mains probably depending on the quality and quantity of the organic matter. Typically 85% of the VFA was acetate and 10% propionate; the remainder was formate, n-butyrate and iso-butyrate. Observed sulfide production rates from the sewer biofilms were typically 0.05 and 0.005 g S/m2 h at 12 and 4 °C, respectively. A high sulfide production rate corresponded with a high VFA concentration. TOC removal was observed in the pressure mains.

A Possible Mechanism for a Light-Driven Regulation of the Fatty Acid Composition in Galactolipids of Chloroplasts

1979 ◽  
Vol 34 (9-10) ◽  
pp. 815-819
Author(s):  
A. Sauer ◽  
K .-P. Heise
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Unsaturated Fatty Acids ◽  
Specific Activity ◽  
Physiological State ◽  
Phospholipid Fraction ◽  
Chromatographic Behavior ◽  
Acyl Acceptor ◽  
Lipid Mixture ◽  
Spinach Leaves

Abstract The occurrence of acylgalactosylglycerol (AGG) in spinach chloroplasts is proposed. In lipid se­parations of whole spinach leaves this fraction is hidden by variable amounts of extraplastidary steryl glucoside (SG) which depended on the physiological state of the leaf material. Beside the phospholipid fraction, this lipid mixture with unique chromatographic behavior, recently termed GL, exhibited the highest specific activity in the lipid extract of infiltrated leaf sections of spinach after short periods of illumination (2 min) under 14C-fixing conditions. The main source of label was found in the fatty acid residues of the lipids described. The decrease of specific activity in GL after a cold chase was accompanied by an increasing 14C-incorporation into the fatty acid moieties of the MGDG-as well as the phospholipid fraction. This effect was significantly reduced if the 14C-pulse was followed by a dark period. This incorporation behavior suggests, that AGG functions as an intermediary acyl acceptor in the light driven fatty acid transfer between the lipids decribed. SG-synthesis, on the contrary, is independent of additional illumination and seems to be localized outside the chloroplast. The last notion was derived from experiments involving the in­ corporation of [UDP-14C] glucose into SG by spinach leaf homogenates. With regard to the increasing level of trienoic fatty acids in AGG and MGDG during the regeneration of dark pretreated spinach leaves in the light, the data are interpreted in terms of a light regulated acylation of AGG with specific unsaturated fatty acids.

Incorporation of [1-14C] and [3-14C] butyrate into milk constituents by the perfused cow's udder

1960 ◽  
Vol 27 (2) ◽  
pp. 151-160 ◽  
Author(s):  
Monique Lauryssens ◽  
R. Verbeke ◽  
G. Peeters ◽  
M.-Thérèse Reinards
Keyword(s):  
Fatty Acids ◽  
Sodium Acetate ◽  
Volatile Fatty Acids ◽  
Specific Activity ◽  
Krebs Cycle ◽  
Acid Synthesis ◽  
Satisfactory Explanation ◽  
C Distribution ◽  
Total Fatty Acids ◽  
Very High

SummaryOne half-udder from a lactating cow was perfused for 110 min with blood containing 1 mc of [1-14C]butyrate. Inactive sodium butyrate was added at the eightieth minute. The volume of milk collected was 320 ml. One half-udder from another cow was perfused for 120 min in the presence of 0·5 mc [3-14C]butyrate, inactive sodium acetate being added at the sixtieth minute. The volume of milk collected was 150 ml.The total amount of 14CO2 recovered was 5·7% of the [1-14C]butyrate given and 7·6% of the [3-14C]butyrate given. In both instances casein, followed by the volatile fatty acids, showed the highest specific activity of the constituents isolated from the milk. The glyceride fatty acids in the udder were fifty times as active as those in the milk. With [3-14C]butyrate the activity of the total fatty acids amounted to 24% and that of total lactose to 0·38% of the added 14C. Butyrate did not appear to be used for glycogenesis in the perfused gland. The specific activity of the lower fatty acids of both the udder and the milk increased stepwise with increasing chain length to reach a maximum at C10. A satisfactory explanation for this peculiar 14C distribution cannot be given at the present time. There was no evidence of direct esterification of butyrate. Most of the activity of casein was due to labelled glutamic and aspartic acids, the activity of the former being four times as high as that of the latter. The acids of the Krebs cycle isolated from the udder tissue when [3-14C]butyrate was given showed very high activity. No striking differences were observed between the results of the two experiments. It is concluded that butyrate is split into two C2 components which behave identically. These are utilized for fatty acid synthesis and take part in the Krebs cycle. The relative 14C distribution between the components isolated from milk and those from tissue may be a reflexion of the secretory processes in the udder cells, synthesized fat tending to be secreted in the alveoli after the other constituents.

Milk yield and composition of milk and blood as indicators of energy intake by Jersey cows

1974 ◽  
Vol 25 (4) ◽  
pp. 657 ◽  
Author(s):  
TH Stobbs ◽  
DJ Brett
Keyword(s):  
Fatty Acids ◽  
Fatty Acid Composition ◽  
Oleic Acid ◽  
Fatty Acid ◽  
Energy Intake ◽  
Acid Composition ◽  
Milk Yield ◽  
Milk Fat ◽  
Fatty Acid Content ◽  
Jersey Cows

Jersey cows were used in a change-over design to examine the effect of three levels of energy intake (lucerne hay at 100, 75 and 50% ad lib.) on milk yield, milk composition, fatty acid composition of milk fat, and blood metabolites (non-esterified fatty acids, glucose and total ketones) to determine which measurement was the most accurate indicator of intake of energy. Milk yields averaged 9.9, 8.7 and 7.2 kg/cow/day with relative intakes of 100, 75 and 50% of ad lib. When energy was restricted the proportion of C4–C16 fatty acids in milk fat decreased (72, 69 and 59%), while the proportion of oleic acid increased (15, 18 and 26%). These changes occurred within approximately 6 days on new energy levels. Fore milk and strippings had similar fatty acid proportions. Restriction of energy reduced the solids not fat, protein and casein contents of milk, and increased its butter fat percentage. Non-esterifred fatty acid levels in blood plasma increased with restriction of feed (348, 528 and 579 µ-equiv./l). Glucose and ketone bodies of blood averaged 58 mg/100 ml and 9.1 mg/100 mi respectively, and did not vary between treatments. It is concluded that milk production is the most sensitive indicator of the intake of digestible energy where change-over designs are used. However, when individual animal variation is not removed in the analysis, the intake of energy is most closely correlated with the fatty acid composition of milk fat (r = 0.73 and –0.74 for C4–C16 acids and oleic acid respectively). Significant correlations with the protein to fat and casein to fat ratios of milk were also measured (r = 0.64 and 0.63 respectively). There was a poor relationship between energy intake and blood composition (r = –0.25 for non-esterified fatty acid content).

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