Volatile Fatty Acids in the Rumen of the Sheep

Gray, F. V.; Pilgrim, A. F.; Rodda, H. J.; Weller, R. A.

doi:10.1038/167954a0

Cited by 37 publications

(33 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It is possible that propionylcholine might make its appearance in a similar way from choline, an ubiquitous tissue constituent, and propionic acid, formed with other lower fatty acids (cf. Gray, Pilgrim, Rodda & Weller, 1951) in the ruminant stomach and thence absorbed into the blood stream (Reid, 1950). We do not think this likely, as care was taken to avoid evaporating our extracts to dryness and the bath temperature was not allowed to exceed 400 C. Smith (1952) has pointed out that a single substance may, in the presence of salt and in an improperly equilibrated column, migrate as more than one band.…”

Section: Discussionmentioning

confidence: 99%

The occurrence of homologues of acetylcholine in ox spleen

Banister¹,

Whittaker²,

Wijesundera³

1953

The Journal of Physiology

View full text Add to dashboard Cite

Section: Discussionmentioning

confidence: 99%

The occurrence of homologues of acetylcholine in ox spleen

Banister¹,

Whittaker²,

Wijesundera³

1953

The Journal of Physiology

View full text Add to dashboard Cite

“…In two out of three cows, the infusion of butyric acid caused a considerable increase in the proportion of acetic acid and a decrease in that of propionic acid in addition to the expected increase in the proportion of butyric acid, and in one cow the original pattern was not recovered when the infusion was stopped. It is known that there is interconversion between all volatile fatty acids in the rumen (Gray, Pilgrim, Rodda & Weller, 1952; Sheppard, Forbes & Johnson, 1959; Gray, Jones & Pilgrim, 1960) and that between acetate and butyrate appears to be quantitatively the most significant (Bergman, Reid, Murray, Brockway & Whitelaw, 1965). However, no comparable change in the pattern of fermentation has been observed when intraruminal additions of acids have been made to diets containing more usual proportions of hay to concentrates (Rook, Balch, Campling & Fisher, 1963 …”

Section: Discussionmentioning

confidence: 99%

The relationship in the cow between milk-fat secretion and ruminal volatile fatty acids

Storry¹,

Rook²

1966

Br J Nutr

View full text Add to dashboard Cite

I . The effect of reducing the hay and of increasing the proportions of concentrate and flaked maize in the diet of cows on the secretion of milk fat and its component fatty acids and on the proportions of volatile fatty acids in the rumen liquor has been studied. 2. The low-hay diet caused a fall in the milk fat content to about half of the values in the initial control period and the secretion of all the major fatty acids in the milk was reduced. The general pattern of change in the proportions of rumen VFA during the change to the low-hay diet was a decrease in acetic acid, an increase in propionic and n-valeric acids, relatively little change in n-butyric acid and also an increase in the concentration of lactic acid. Approximately 60 % of the variation in milk fat content during the change of diet was associated with the increase in propionic acid. 3. In cows established on the low-hay diet there were marked variations in the relative proportions of acetic and propionic acids, but there was no related change in milk fat content. On return of the animals to the high-hay diet, recovery of the initial proportions of acetic, propionic and valeric acids occurred within about 4 days but the recovery in milk fat content was not complete until 2-3 weeks had elapsed. 4. Although the intraruminal infusion of acetic acid in cows on the low-hay diet caused increases and decreases respectively in the molar proportions of acetic and propionic acids in the rumen, an increase in milk fat content was observed amounting to only one-quarter of the loss associated with the transfer to the low-hay diet; there was no characteristic pattern of increase in the yields of the individual fatty acids of milk fat.No consistent effects of intraruminal infusions of butyric acid, in cows on the low-hay diet, on the yield of milk fat or of the individual fatty acids were observed.There is much circumstantial evidence that the fall in milk fat content frequently observed in milking cows during a change from a diet containing a usual amount of hay to one containing only a small amount is related to the associated decreased and increased proportions of acetic and propionic acids respectively in the volatile fatty acids of the rumen digesta. Marked variations from cow to cow in the extent and rapidity of the fall in fat content are, however, observed, and on the abrupt return of cows from a diet low in hay to one containing a usual amount, the recovery of the original fat content is not immediate but takes place progressively over a period of up to 3 weeks (Balch, Balch, Bartlett, Cox & Rowland, 1952; King & Hemken, 1962; Storry & Rook, 1 9 6 5~) .Also when intraruminal additions of dilute acetic acid or of sodium acetate are given to cows receiving a diet low in hay and in whose milk the fat content has been depressed, the observed increases in milk fat content vary widely from cow to cow (Stoddard, ruminal volatile fatty acids that occur during a change from a diet containing a usual amount of hay to one containing only a small amount, and of...

show abstract

“…It is evident from earlier work (Gray et al 1951(Gray et al , 1952 and from more recent reports (e.g. Leng and Leonard 1965) that this could be largely accounted for by the condensation of acetate molecules to form butyrate.…”

Section: C Concentration In Composite Sample Of Rumen Fluidmentioning

confidence: 91%

The rates of production of volatile fatty acids in the rumen. IV. Individual and total volatile fatty acids

Weller¹,

Gray²,

Pilgrim³

et al. 1967

Aust. J. Agric. Res.

View full text Add to dashboard Cite

1) In sheep fed at 12-hr intervals on roughage diets (lucerne and wheaten hay) total volatile fatty acid production in the rumen has been measured by an isotope dilution procedure based on the infusion of a single 14C-labelled volatile fatty acid.(2) Total and individual acid production has been measured through the infusion of a mixture of 14C-labelled acids in which the proportions of individual acids were such that transfers of 14C by interconversions between the acids were balanced.(3) The findings support the view that the mixture of acids produced in the rumen is similar in composition to that present in the rumen fluid throughout the feeding cycle. Consequently it was possible to determine the production of individual acids by a relatively simple procedure ~equiring only the infusion of a single 14Clabelled acid and measurement of the concentration of 14C in a composite sample of the acids in the rumen fluid collected throughout the feeding cycle. This procedure is considered suitable for routine use; automatic sampling of rumen fluid still further reduces the work involved.(4) The infusion of certain mixtures of 14C-labelled fatty acids showed that the composition of the acid initially formed in the rumen was acetic 77-83%, propionic 15-18 %, and butyric 1-7 % according to the diet given and the time elapsed after feeding. From 50 to 80% of the butyric acid in the final volatile acid product was formed from acetic acid. Degradation of 14C-labelled butyrate formed from [I-14C] acetate in the rumen showed 93 % of the 14C to be nearly evenly divided between carbon atoms C, and C,.In previous experiments (Gray et al. 1966) production of total volatile fatty acid (VFA) in the rumen of a sheep was measured by an isotope dilution procedure based on continuous infusion of 14C-labelled VFA into the rumen throughout a feeding cycle. The mixture of acids infused was one in which the 14C was distributed between acetic, propionic, and butyric acids in proportions similar to those in which the corresponding unlabelled acids occurred in the rumen fluid.The present work shows that:(1) Any mixture of the labelled acids, or any one of them alone, can be used to determine the total acid produced during a feeding cycle.(2) Infusion of a suitable mixture, based on the observed behaviour of each labelled acid in the rumen, makes it possible to determine the quantity of each acid formed.

show abstract

Volatile Fatty Acids in the Rumen of the Sheep

Cited by 37 publications

References 5 publications

The occurrence of homologues of acetylcholine in ox spleen

The occurrence of homologues of acetylcholine in ox spleen

The relationship in the cow between milk-fat secretion and ruminal volatile fatty acids

The rates of production of volatile fatty acids in the rumen. IV. Individual and total volatile fatty acids

Contact Info

Product

Resources

About