Subcellular compartmentation in the synthesis of the milk sugars lactose and ?-2,3-sialyllactose

Leong, Weng S.; Navaratnam, Naveenan; Stankiewicz, Margaret J.; Wallace, A.V.; Ward, Simon; Kuhn, Nicholas J.

doi:10.1007/bf01322597

Cited by 17 publications

(13 citation statements)

References 53 publications

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“…Supplemented ewes not only produced more colostrum than unsupplemented ewes but also the colostrum they produced was more liquid and this, in turn, was associated with higher levels of lactose. Lactose is osmotically active (Leong et al, 1990) so draws water from the blood and, in doing so, decreases the viscosity of the colostrum. The ewes with colostrum of highest viscosity and at the same time the lowest concentration of lactose were the unsupplemented ewes regardless of whether they bore twin or single lambs.…”

Section: Discussionmentioning

confidence: 99%

Effect of supplementation of ewes with barley or maize during the last week of pregnancy on colostrum production

Banchero

Quintans

Vázquez

et al. 2007

Animal

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The experiment tested the hypothesis that short-term feeding of barley just before lambing would be as effective as maize in stimulating early production of colostrum. Both grains are high in starch, and should provide a substrate for lactose which, in turn, promotes lactogenesis. Thirty-five Corriedale ewes bearing single foetuses and 25 bearing twin-foetuses from a synchronised mating were fed on pasture during most of gestation. Fourteen days before the expected time of lambing the single-and twinbearing ewes were allocated to three treatments and fed (1) a basal diet of lucerne hay to meet their nutrient requirements, (2) the basal diet plus a supplement of whole barley; or (3) the basal diet plus a supplement of cracked maize. The twin-bearing control ewes accumulated more colostrum than the single-bearing control ewes at birth (292 v. 190 g). However, supplementation with barley or maize increased the colostrum at birth to 360 and 541 g in singles and 648 and 623 g in twins. We conclude that barley is a good alternative to maize to stimulate production of colostrum especially in twin-bearing ewes whose lambs are the most likely to benefit from the supplement.

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Section: Discussionmentioning

confidence: 99%

Effect of supplementation of ewes with barley or maize during the last week of pregnancy on colostrum production

Banchero

Quintans

Vázquez

et al. 2007

Animal

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“…Progesterone inhibits α-lactalbumin, one of the proteins required for the synthesis of lactose synthetase, the rate-limiting enzyme for lactose synthesis. Since lactose osmotically draws water into the mammary secretory epithelium [34,35], any delay in lactose synthesis would limit the production of colostrum. In addition, the colostrum that is produced would have a high viscosity and therefore be difficult for the lambs to suck [36,37].…”

Section: Discussionmentioning

confidence: 99%

Endocrine and metabolic factors involved in the effect of nutrition on the production of colostrum in female sheep

Banchero

Clariget²,

Bencini

et al. 2006

Reprod. Nutr. Dev.

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-We investigated the physiological relationship between diet during pregnancy and colostrum production in ewes to test the hypothesis that for ewes that are in low body condition, with low fat reserves, the food supply will be the main source of energy for colostrum synthesis. To this end, we measured the amount of colostrum accumulated by ewes under two levels of nutrition. We also measured the circulating concentrations of metabolites and hormones associated with lactogenesis (β-hydroxybutyrate, glucose, progesterone, prolactin, cortisol, growth hormone, leptin, insulin and insulin-like growth factor-I) Ewes were either under-fed at 70 (n = 15) or well-fed at 110% (n = 10) of their daily metabolisable energy requirement during the last two months of pregnancy. Colostrum accumulation up to parturition was 168 ± 48 g for under-fed ewes and 451 ± 103 g for well-fed ewes. After birth, under-fed ewes produced less colostrum than well-fed ewes but the difference was no longer significant. The level of nutrition also influenced the plasma concentrations of hormones and metabolites related to lactogenesis. Progesterone concentrations decreased before lambing in all animals but in under-fed ewes the fall appeared to be too small to initiate the onset of colostrum production. β-hydroxybutyrate concentrations were higher in under-fed than in well-fed ewes, suggesting that the under-fed ewes were mobilising more adipose tissue but they still did not meet their ME requirements for colostrum production. We concluded that, in underfed ewes, there are insufficient nutrients for adequate lactation and the hormone regime is inappropriate for good udder development and colostrum synthesis. udder development / lactogenesis / β-hydroxybutyrate / glucose / progesterone / prolactin / cortisol / growth hormone / leptin / insulin / insulin-like growth factor-I / lamb mortality

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“…However, the activation of sialyltransferase, in the synthesis of sialyllactose, by basic proteins implies that this form of control is not unique to lactose synthetase (Leong et al, 1987(Leong et al, , 1990.…”

Section: Cation Binding By Lactose Synthetasementioning

confidence: 95%

“…Rat mammary tissue contains particulate sialyltransferase activity, which exhibits a Km towards lactose of about 1 mM and yields mainly (X(2~3)sialyllactose with a little (X(2~6)sialyllactose (Carlson et al, 1973;Leong, 1988;Leong et al, 1990). A detailed study has been made of the way in which this enzyme, acting within tightly sealed vesicles of Golgi membrane origin, can be fed with lactose by lactose synthetase (Leong et al, 1990).…”

Section: Metabolic Activity Of Mammary Cells 1147mentioning

confidence: 97%

See 1 more Smart Citation

Physiology and Biochemistry of Lactation

Mepham¹,

Kuhn²

1994

Marshall’s Physiology of Reproduction

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Subcellular compartmentation in the synthesis of the milk sugars lactose and ?-2,3-sialyllactose

Cited by 17 publications

References 53 publications

Effect of supplementation of ewes with barley or maize during the last week of pregnancy on colostrum production

Effect of supplementation of ewes with barley or maize during the last week of pregnancy on colostrum production

Endocrine and metabolic factors involved in the effect of nutrition on the production of colostrum in female sheep

Physiology and Biochemistry of Lactation

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