Butyrate as a Precursor of Milk Constituents in the Intact Dairy Cow

Single-dose infusion of sodium butyrate, but not lactose, increases plasma β-hydroxybutyrate and insulin in lactating dairy cows

“…In addition to the energy characteristics of butyrate, a clear link exists to glucose and lipid metabolism (Kleiber et al, 1954;Black et al, 1961) as well as milk production in the lactating dairy cow (Seymour et al, 2005). Based on an evaluation of multiple studies (Seymour et al, 2005), ruminal butyrate concentration (R 2 = 0.47) was reported to be more closely related to milk production than propionate (R 2 = 0.23) or acetate (R 2 = 0.03).…”

Recent research on the origin of milk fat

“…They are formed, if Popjak et al are right, by a conversion of /?-hydroxybutyrate to butyrate followed by condensation with acetate, in the presence of an adequate supply of acetate, butyrate should thus be as good a precursor of milk-fatty acids as either /?-hydroxybutyrate or acetate itself. Kleiber, Black, Brown, Luick, Baxter & Tolbert (1954) and Rogers & Kleiber (1956) found that much less labelled butyrate than acetate was incorporated into milk-fatty acids by the living cow, but that there was substantial incorpora tion of butyrate into lactose. Lauryssens, Verbeke & Peeters (1957) also found low incorporation of butyrate carbon into fatty acids by the perfused udder.…”

“…The experiments with labelled acetate Cowie et at. 1951), with /Miydroxybutyrate (Kumar & Lakshmanan 1954) and with butyrate (Kleiber et al 1954 ; illustrate the difficulties and even dangers of interpreting relative specific activities of components of samples collected from a dynamic system at only one or two points in time. Thus Popjak et al concluded (1) th at all the fatty acids up to palmitic were synthesized in the udder from acetate by way of a C4-compound to the pool of which /i-hydroxybutyrate contributed; and (2) th at (because of their low specific activity) the C18 acids were not synthesized by this route but were (probably) derived from blood lipids.…”

The biosynthesis of lactose

“…In a series of papers (Kleiber, Smith, Black, Brown & Tolbert 1952;Kleiber, Black, Brown & Tolbert 1953;Kleiber, Black, Brown, Luick, Baxter & Tolbert 1954) in which they studied the distribution of 14C in various milk constituents, including lactose, after the injection of labelled fatty acids intravenously into lactating cows, Kleiber and his co-workers have come to the general conclusions that, (i) the incorporation of 14C into lactose follows closely the pattern of 14C incorporation into plasma glucose, and (ii) the ratio of a time function of the average specific activities of lactose samples formed during a period of 2 days after the injection to a similar function of the average specific activities of the plasma glucose over the same period, was always less than one, a value of 0-84 being typical for the substrates used. This value, expresses ' the maximum per cent of lactose th at could have been derived from plasma glucose, assuming th at all 14C activity found in the lactose had passed through the plasma glucose pool ' (Baxter et al 1956).…”

“…The intravenous injection of labelled bicarbonate (Kleiber, Smith & Black 1952), propionate (Kleiber et al 1953), butyrate (Kleiber et al 1954), caproat 1956) and formate (Carleton, Roberts & Nutting 1957;Misler, Tumerman & Roberts 1958) has, in every case, shown the formation of lactose incorporating small amounts (< 10%) of the 14C injected. In all these cases extramammary glucose formation from the labelled precursor is the most likely explanation of the results.…”