The Microbiological Assay of ‘Vitamin B<sub>12</sub>’ in the Milk of Different Animal Species

Gregory, Margaret E.

doi:10.1079/bjn19540051

Cited by 99 publications

(57 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…General The folate binding in milk exemplifies a type of passive trapping process that is already familiar from thc literature on the protein binding of vitamin B,, in milk (Gregory, 1954;Gregory & Holdsworth, 1955) and of steroid hormones in blood (cf. Jensen &Jacobson, 1962; Briggs & Brotherton, 1970).…”

Section: Whole Body Folate In the Kidmentioning

confidence: 99%

Folate nutrition in the kid

Ford¹,

Knaggs²,

Salter³

et al. 1972

Br J Nutr

View full text Add to dashboard Cite

I. A study was made on the folate content of goat's milk in relation to stage of lactation, and on the interrelationship between blood and milk folate concentrations in the dam and in the kid.2. In seven goats the folate concentration in the colostrum at parturition ranged from 136 to 300 ng/ml, and averaged 205 ng/ml. The concentration fell sharply during the early days of lactation and by day 14 it averaged only 9-5 nglml. This pattern of rapid decline in milk folate concentration with advancing lactation was little affected by daily provision of folic acid parenterally in relatively large amounts.3. The colostrum and milk contained a minor whey protein that combined strongly with folate, and presumably acts as a trapping mechanism to accumulate the vitamin from the plasma into the milk. The milk folate concentration is determined by the rate of milk secretion in relation to the availability of free folate in the blood plasma. 4.At parturition the plasma folate concentration in the kids was very low -about I nglmlbut by day 2 it had increased to about 28 ng/ml. This folate was protein-bound and accompanied by an excess of free binder protein. It appeared that the folate-protein complex from the colostrum was transmitted intact into the kids' blood circulation.5. The possible importance of the folate-binding protein in the regulation of folate metabolism is discussed.Goat's milk is a comparatively poor source of folate. It contains about 6 n g / d as against 50 ng/ml in human milk and cow's milk, and its prolonged consumption as the sole diet by suckling infants may cause 'goat's milk anaemia', which is now recognized as being a megaloblastic anaemia symptomatic of folate dcficiency (Becroft & Holland, 1966). In man the metabolic turnover of folate is rapid and any severe restriction of dietary intake is quickly followed by a fall in serum folate and a slower progressive fall in red cell folate (Herbert, 1962). Thcse observations prompted speculation on the folate nutrition of the newborn kid, and the present papcr reports on the folate content of goat's milk in relation to stage of lactation, and on some interrelationships between blood and milk folate concentrations in the dam and in the kid. E X P E R I M E N T A LPedigree British Saanen goats of the Institute herd were used. They were maintained on clover hay and concentrates and given daily access to pasture. They were brought indoors each evening and housed on concrete in individual pens. On the expected day of parturition and for about a week thereafter the goats were kept indoors. The kids remained in the pens for 3 weeks, during which time they were suckled by their dams and also had access to hay and concentrates.Some of the goats were milked pre-partum, as deemed necessary by the goatherd, https://www.cambridge.org/core/terms. https://doi

show abstract

Section: Whole Body Folate In the Kidmentioning

confidence: 99%

Folate nutrition in the kid

Ford¹,

Knaggs²,

Salter³

et al. 1972

Br J Nutr

View full text Add to dashboard Cite

show abstract

“…This left a dry residue from which virtually all inorganic and organicallybound P had been removed, except that in the nucleic acid fraction (see p. 298). 32P was counted in this residue and total nucleic acid-P (NA-P) incorporation estimated from this activity and the specific activity of the inorganic phosphate in an ultrafiltrate (Gregory, 1954) prepared from the rumen contents used in each incubation.…”

Section: Estimation Of Bacterial Protein Synthesismentioning

confidence: 99%

“…Samples (25 g) were withdrawn at zero time and at intervals after the start of the incubation period and acidified with 5 n12 M-hydrochloric acid to stop fermentative activity. The acidified samples were strained through four layers of surgical gauze, ultrafiltered (Gregory, 1954) and the ultrafiltrates stored at -20" to await analysis for urea, GU, glucose or ammonia.…”

Section: Incubation and Processing Of Samplesmentioning

confidence: 99%

See 1 more Smart Citation

Glycosyl ureides in ruminant nutrition

Merry¹,

Smith²,

McAllan³

1982

Br J Nutr

View full text Add to dashboard Cite

1. The fate of glucosyl urea (GU), lactosyl urea (LU) and corresponding mixtures of the free sugars and urea and their degradation products were examined during in vitro incubation of the compounds with rumen contents taken from donor sheep and steers at various stages of adaptation to these compounds.2. The sugar-urea bond was virtually unattacked in rumen contents from unadapted sheep and steers but generally a slow release of the galactose moiety occurred. After feeding LU or GU to animals for a period of approximately 10 d, the rates ofdisappearance of both bound urea and sugar had increased, but were still markedly slower than those of the corresponding free sugars and urea. In vitro rates of degradation of both free lactose and urea also increased in response to the feeding of lactose and urea to rumen content donor animals.3. Ammonia accumulation in rument contents when GU or LU were the substrates was notably lower than when equivalent amounts of glucose and urea or lactost: and urea were the substrates. 4.Bacterial growth was estimated using an vitro method based on incorporation of 32P into bacterial nucleic acids. Markedly different patterns of bacterial growth were observed depending on whether LU or lactose and urea were the substrates.

show abstract

“…Vitamin B6 was assayed with Kloeckera apiculata (brevis) as described by Barton-Wright (1963) except that the samples were extracted with 0·05 M HCl as recommended by Gregory (1959). Vitamin B12 was assayed with Lactobacillus leichmannii as described by Gregory (1954). Thiamine was assayed with Lactobacillus fermentum 36; the test medium was that of Banhidi (1958) and the samples were extracted by heating for 30 min at 100°C with 0·016 M H 2 S04, For the determination of retinol, ex-tocopherol and active carotenes, samples of the milk or, in some instances, of the separated cream were diluted with warm distilled water.…”

Section: Analysis Of Milk Samplesmentioning

confidence: 99%

Composition of Milk from Red and Grey Kangaroos with Particular Reference to Vitamins

Poole¹,

Sharman²,

Scott³

et al. 1982

Aust. Jnl. Of Bio. Sci.

View full text Add to dashboard Cite

Analysis of milk from red and grey kangaroos confirmed that the composition of milk from individual mammary glands changes with advancing age of the associated suckled young. Although the proportion of particular components may change, concentration of solids, in particular fats and to a lesser extent protein and casein, increase throughout lactation. The results of analyses to determine the vitamin content of kangaroo milks are presented for the first time.

show abstract

The Microbiological Assay of ‘Vitamin B₁₂’ in the Milk of Different Animal Species

Cited by 99 publications

References 16 publications

Folate nutrition in the kid

Folate nutrition in the kid

Glycosyl ureides in ruminant nutrition

Composition of Milk from Red and Grey Kangaroos with Particular Reference to Vitamins

Contact Info

Product

Resources

About

The Microbiological Assay of ‘Vitamin B12’ in the Milk of Different Animal Species

Cited by 99 publications

References 16 publications

Folate nutrition in the kid

Folate nutrition in the kid

Glycosyl ureides in ruminant nutrition

Composition of Milk from Red and Grey Kangaroos with Particular Reference to Vitamins

Contact Info

Product

Resources

About

The Microbiological Assay of ‘Vitamin B₁₂’ in the Milk of Different Animal Species