Identification of the volatile fatty acid in the peripheral blood and rumen of cattle and the blood of other species

Abstract

Volatile fatty acid isolated from nine samples of peripheral blood from four cows contained, on a molecular basis, from 90.0 to 97.0 per cent. of acetic acid (mean 93.3 per cent.). The remainder comprised, as mean values, propionic acid, 2.39 per cent.; butyric acid, 2.61 per cent.; and a group of at least three acids between butyric and octanoic, 1.84 per cent. The significance of the high proportion of acetic acid in the volatile fatty acid of bovine peripheral blood is discussed. Only traces of esterified acids lower than octanoic could be found in bovine blood lipides. Volatile fatty acids were found also in the blood of the rabbit, guinea pig, horse, and pig and in human plasma. Here again a high proportion of acetic acid was recorded. Volatile fatty acid isolated from nine samples of ruminal contents from two cows contained on a molecular basis from 52.3 to 69.0 per cent. of acetic acid (mean 60.0 per cent.). The remainder comprised, as mean values, propionic acid, 21.8 per cent.; butyric acid, 14.4 per cent.; and acids higher than butyric (apparently largely valeric and hesanoic), 3.8 per cent. This limited number of analyses indicated no gross effect of type of feed on the proportion of the acids in the rumen.

The osmotic pressure and the concentration of some solutes of the intestinal contents and the faeces of the cow, in relation to the absorption of the minerals

“…The concentration of steamvolatile fatty acids in the arterial blood of the cow is around 0-03 to 0-25 m-osmoles/lOOml. (McClymont, 1951). With the exception of the duodenum the concentration of the steam-volatile fatty acids is always higher in the intestinal tract than in the blood and very much higher in the caecum and large intestine.…”

Influence of the nature of carbohydrate intake on the absorption chronology of reducing sugars and volatile fatty acids in the pig

“…A VFA mixture appears along the various stages of the efferent intestinal blood and the concentrations are highest in the coecocolic blood (Barcroft et al, 1944). The VFA profile has been measured in the peripheral blood of pigs (McClymont, 1951 in the portal blood (Friend et al, 1964) and more recently in both the arterial and portal blood (R6rat et al, 1985;Topping et al, 1985;Yen et al, 1991 ). Significant amounts of these substances are used by the enterocytes for their own metabolic needs during transport (Ly, 1974;Imoto and Namioka, 1978a, b).…”

Specific Dynamic Action of Acetic Acid and Heat Increment of Feeding in Ruminants

“…of the metabolizable energy of the food (gross energy minus energy lost in faeces, urine, and methane) was first described by Armsby and Fries in 1903, and has been repeatedly confirmed (Ritzman and Benedict 1938;Kriss 1928, 1930;Marston 1949). The findings that acetic acid is a major product of ruminal digestion (Barcroft, McAnally, and Phillipson 1944;Elsden et al 1946;Marston 1948;KiddIe, Marshall, and Phillipson 1951;McClymont 1951a), that on a roughage diet virtually no enzymically digestible carbohydrate escapes ruminal fermentation to the volatile fatty acids (Heald 1951;McClymont 1949), and that acetic acid is a major tissue metabolite of ruminants (Reid 1950;McClymont 1951b), strongly suggest that the high heat increment of feeding of ruminants may be largely attributable to the high S.D.A. of the acetic acid produced in ruminal fermentation.…”

“…Other minor products of ruminal fermentation such as valeric and hexanoic acids (McClymont 1951a;Gray et al 1951) will contribute three or nil carbon atoms for glyconeogenesis, depending on whether they contain an odd or even number of carbon atoms, and the remaining atoms will follow the pathways of acetic and butyric acids.…”