Review and an experimental study on the physiological and quantitative aspects of gluconeogenesis in lactating ruminants

Danfær, A.; Tetens, Vilhelm; Agergaard, N.

doi:10.1016/0305-0491(94)00242-m

Cited by 96 publications

(78 citation statements)

References 26 publications

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“…Glu and Gln are also important precursors for glucose synthesis (Black et al, 1990) and when given intravenously, they could have contributed to the higher milk lactose yield. Danfaer et al (1995) reported from the literature a wide range of estimates (2 to 40%) of the proportion of glucose derived from AA, and they found in their own study with lactating goats that portally infused AA could contribute to 36% of the hepatic glucose production. They concluded that the contribution of AA to glucose synthesis was regulated to a great extent by the availability of substrates.…”

Section: Discussionmentioning

confidence: 99%

“…Hepatic metabolism of glucogenic AA into glucose synthesis is to a great extent regulated by the availability of substrates (Danfaer et al, 1995). When glucose supply is limited, particularly in early lactation, the use of AA as glucose precursors may be high to prevent the shortfall of glucose (Danfaer et al, 1995).…”

Section: Discussionmentioning

confidence: 99%

“…When glucose supply is limited, particularly in early lactation, the use of AA as glucose precursors may be high to prevent the shortfall of glucose (Danfaer et al, 1995). The infusion of glucose could spare almost twice its own weight of glucogenic AA (Krebs, 1964).…”

Section: Discussionmentioning

confidence: 99%

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Post-ruminal or intravenous infusions of carbohydrates or amino acids to dairy cows 1. Early lactation

Schei

Danfær²,

Boman

et al. 2007

Animal

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The objectives of this study were to compare the effects of post-ruminal and intravenous infusions of wheat starch or glucose (CHO) or a mixture of amino acids (AA) on milk protein yield, nitrogen utilisation, plasma metabolites and mammary extraction rate of dairy cows in early lactation. Eight cow, ruminally fistulated, was assigned to two 4 £ 4 Latin squares during 14-day periods, where the last 7 days were for infusions. Infusions were: (1) starch in the abomasum (SP), (2) glucose in the blood (GB), (3) AA in the abomasum (AP), and (4) AA in the blood (AB). The experiment started 54^4 days (mean^S.E.) post partum (milk yield 33.4^1.7 kg). Daily amounts of nutrients infused were 378, 365, 341, and 333 g for SP, GB, AP and AB, respectively. The cows were fed a basal diet consisting of a concentrate mixture and grass silage (55:45 on dry-matter (DM) basis), and DM intake was 17.2 kg/day. Milk production was affected by site of infusion within substrate, whereas infusion substrates within infusion site (CHO or AA) were of minor importance. Compared with SP infusion, GB infusion increased ( P , 0.05) milk protein yield and concentration by 55 g and 1 g/kg. The AB infusion tended to ( P , 0.10) increase milk yield and ECM and increased ( P , 0.05) protein yield and concentration by 1.8 and 2.2 kg, 83 g and 1.1 g/kg compared with AP infusion, respectively. Nitrogen balance data indicated higher losses of metabolic faecal nitrogen (MFN) by abomasal than by intravenous infusions, and an increased ( P , 0.05) catabolism for AP and AB infusions compared with SP and GB infusions. GB infusion did not increase ( P . 0.10) plasma glucose or insulin concentrations above that of SP infusion. Compared with the SP infusion, the GB infusion had minor effect on plasma AA. AP infusion increased ( P , 0.05) plasma non-essential AA (NEAA) concentration compared with AB infusion, whereas infusion site of AA had no effect ( P . 0.05) on essential AA (EAA) or branched-chain AA (BCAA). Although a higher milk protein synthesis was observed for AB infusion, the mammary extraction rate was not higher ( P . 0.05) than for AP infusion. Across infusion site, AP and AB infusions increased plasma concentration of EAA and BCAA, but compared with GB infusion, the mammary extraction rates tended ( P , 0.10) to be lower. It is concluded that abomasal nutrient infusion increases loss of MFN and that the gastrointestinal metabolism influences the nutrients available for milk synthesis. Our conclusion is that when glucose was infused, AA limited a further milk protein synthesis, but when AA was infused, glucose or energy substrate might have been the limiting factor. Our results verify that glucogenic substrates are limiting when cows are in negative energy balance.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Post-ruminal or intravenous infusions of carbohydrates or amino acids to dairy cows 1. Early lactation

Schei

Danfær²,

Boman

et al. 2007

Animal

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“…In ruminants, glucose turnover increases with a number of factors such as energy intake and supply of gluconeogenic substrates to the liver as reviewed, for example by Stangassinger and Giesecke [4], Brockman [2] and Danfaer et al [7]. Data obtained in lactating ruminants also show that the glucose requirements of the animals and their hormonal status have a clear impact on glucose turnover [7][8][9].…”

Section: Introductionmentioning

confidence: 99%

Whole body glucose turnover in growing and non-productive adult ruminants: meta-analysis and review

2003

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-The objectives of the present paper were to review and quantitatively determine the influence of the nutritional factors on whole body glucose turnover in growing and adult non-productive ruminants. A meta-analysis approach was used. The dietary grain: forage ratio significantly increased the slope of the relationship between glucose turnover and metabolisable energy intake. This effect was probably associated with the inclusion of maize rather than any other grain source in the diet. The analysis pointed out the possible differences in response between growing and adult non-productive animals, and suggested that the performance level of the animals (and their glucose requirements) could contribute to regulating whole body glucose turnover. This aspect would warrant further investigation.whole-body glucose turnover / meta-analysis / ovines / bovines

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“…Consequently, in ruminants, recycling of glucose in particular via the Cori cycle is probably more important in cases of glucose deficit, as in fasting animals or in early lactation [43,50] than in situations when the supply of glucose or its precursors is plentiful.…”

Section: Whole Body Glucose Turnover and Propionate Supplementationmentioning

confidence: 99%

Propionate supplementation did not increase whole body glucose turnover in growing lambs fed rye grass

et al. 2003

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-The objective of the present study was to investigate the effects of propionate supplementation on whole body glucose turnover in growing lambs fed frozen rye-grass at 1.5 × maintenance using [1-13 C]-glucose. Intraruminal infusion of propionate (0.55 and 0.91 mol·d -1 ) increased the ruminal molar proportions of propionate from 25% with the control to 40% with the highest propionate treatment. It did not however modify glucose turnover (26 mmol·d -1 ·kg -1 ), nor the conversion of its carbon into L-lactate (21%) and alanine (21%), nor glucose recycling (9%). All of the results suggest that in the present conditions glucose turnover and metabolism were not influenced by the supply of propionate.glucose turnover / propionate / growing lambs / [1-13 C]-glucose

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Review and an experimental study on the physiological and quantitative aspects of gluconeogenesis in lactating ruminants

Cited by 96 publications

References 26 publications

Post-ruminal or intravenous infusions of carbohydrates or amino acids to dairy cows 1. Early lactation

Post-ruminal or intravenous infusions of carbohydrates or amino acids to dairy cows 1. Early lactation

Whole body glucose turnover in growing and non-productive adult ruminants: meta-analysis and review

Propionate supplementation did not increase whole body glucose turnover in growing lambs fed rye grass

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