Determination of total potentially available nucleosides in bovine milk

Abstract

a b s t r a c tBovine colostrum and milk samples were collected from two herds over the course of the first month post-partum, pooled for each herd by stage of lactation and total potentially available nucleosides were determined. Sample analysis consisted of parallel enzymatic treatments, phenylboronate clean-up, and liquid chromatography to quantify contributions of nucleosides, monomeric nucleotides, nucleotide adducts, and polymeric nucleotides to the available nucleosides pool. Bovine colostrum contained high levels of nucleosides and monomeric nucleotides, which rapidly decreased as lactation progressed into transitional milk. Mature milk was relatively consistent in nucleoside and monomeric nucleotide concentrations from approximately the tenth day post-partum. Differences in concentrations between summer-milk and winter-milk herds were largely attributable to variability in uridine and monomeric nucleotide concentrations.

Determination of total potentially available nucleosides in bovine, caprine, and ovine milk

“…Elevated uridine nucleotide levels may, in part, be rationalised on the basis of their role in lactose biosynthesis (Arthur, Kent, & Hartmann, 1991;Linzell & Peaker, 1971) and their potential immunological properties (Kulkarni, Fanslow, Rudolph, & Van Buren, 1986;Van Buren, Kulkarni, Fanslow, & Rudolph, 1985) as has been noted previously (Gill et al, 2011).…”

“…Materials, instrumentation and methods were as described in Gill et al (2011). Sample collection and statistical analysis in the present study are detailed below.…”

“…A mature ovine milk sample (East Friesian) was supplied from a flock of sheep from the Southland region of New Zealand. Upon collection, the samples were taken to the laboratory and immediately prepared for storage in the same manner as previously described (Gill et al, 2011).…”

“…The dietary significance of nucleosides and nucleotides, the forms in which they can exist in milk, their role as semi-essential nutrients in the human diet and their analytical determination in bovine milk have been described in a recent study that formed the basis for the developments currently presented (Gill, Indyk, & Manley-Harris, 2011).…”

“…This analytical strategy allows specific contributions to the TPAN pool from polymeric nucleotides, monomeric nucleotides, nucleosides, and nucleotide adducts to be estimated. Recently, this technique was applied to a lactational study of bovine colostrum and milk given the importance of this component in infant formula production (Gill et al, 2011).…”