Effect of energy metabolism on 13C/12C-ratios in milk fat and lactose of cows

Schulze, E.; Diop, H.; Breves, Gerhard; Giese, W.

doi:10.1016/0305-0491(92)90214-c

Cited by 3 publications

(6 citation statements)

References 13 publications

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“…From here their way into glucose and lactose via gluconeogenesis is predetermined in cases when besides the needed energy large amounts of glucose are required for lactation. Results from fasting cows support this idea and were already submitted for publication [2].…”

Section: Introductionsupporting

confidence: 75%

Preparation of Naturally ¹³C-Rich Free Fatty Acids (FFA) from Corn Oil and their Application in Metabolic Studies of Lactating Cows

Giese¹

1993

Isotopenpraxis Isotopes in Environmental and Health Studies

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When the 13C/'2C ratios in lactose and milk fat of normally fed healthy cows are compared to 13C/'2C in feed a metabolic depletion of I3C in the milk constituents becomes obvious.Due to a carbon isotope effect in the decarboxylation step of pyruvate to Acetyl-Co-A resulting in a 13C depleted acetate, depot fat and milk fat are especially reduced in I3C relative to "C.Under pathophysiological conditions after longer fasting periods or in ketosis, long chain fatty acids from depot fat are metabolized and their I3C depleted carbon atoms enter the citric acid cycle via Acetyl-Co-A. Then the intermediary products of this cycle become I3C depleted too and with a drain on the oxalacetate pool by gluconeogenesis I3C depleted carbon atoms are channeled into lactose.This hypothesis is apt to explain a '3C/12C decrease in lactose of ketotic cows relative to healthy controls. It is supported by the observation that I3C-rich fatty acids from corn oil dosed orally to a ketotic cow increase the I3C/l2C ratios in lactose. So a crossing-over of carbon atoms from long chain fatty acids into glucose and lactose seems highly probable.KEY WORDS isotope abundances 13C/'2C ratios, cows, isotope effects, ketosis, lactose, metabolism milk fat, natural

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Section: Introductionsupporting

confidence: 75%

Preparation of Naturally ¹³C-Rich Free Fatty Acids (FFA) from Corn Oil and their Application in Metabolic Studies of Lactating Cows

Giese¹

1993

Isotopenpraxis Isotopes in Environmental and Health Studies

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“…But only few of these studies were specifically designed to determine (steady-state or true) discrimination between diets and dairy products (milk and milk components). Most experiments either used short equilibration periods [14,25,26], one or a few cows [8,26] or bulk milk samples without knowledge of the exact δ 13 C of the ingested feed [28]. In our literature search, seven studies reported data to calculate discrimination between diet and whole milk, whereas only one study was found for milk-casein discrimination and one for discrimination between lactose and milk fat.…”

Section: Introductionmentioning

confidence: 90%

“…Discrimination values for dairy cattle (or data from which discrimination values can be derived) have been published by several groups [6,8,11,13,14,21,22,[25][26][27][28]. But only few of these studies were specifically designed to determine (steady-state or true) discrimination between diets and dairy products (milk and milk components).…”

Section: Introductionmentioning

confidence: 98%

¹³C discrimination between diet, faeces, milk and milk components

Schneider

Auerswald

Bellof

et al. 2014

Isotopes in Environmental and Health Studies

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Stable isotope analysis is a fundamental tool in food origin and authenticity testing. Its use in livestock production requires knowledge of isotope discrimination between product and diet. Here, we report (13)C discrimination ((13)Δ) for milk, milk components (fat, casein and lactose) and faeces in eight lactating dairy cows, which grazed pasture or were fed fresh pasture herbage in the stall. Cows were supplemented with grain maize at 1.72 kg d(-1) (dry matter). Feed components were collected daily, and faeces, milk fat, casein, lactose and whole milk 4 times per week during an 8-week-long sampling period. Carbon isotope composition (δ(13)C) of each sample was analysed. δ(13)C was lowest in milk fat (-29.8‰) and highest in casein (-26.4‰). Compared to the diet, whole milk was depleted in (13)C ((13)Δ = 0.4‰) due to a strong (13)C-depletion of fat ((13)Δ = 2.2‰), which was not fully compensated by the (13)C-enrichment of casein ((13)Δ = -1.1‰) and lactose ((13)Δ = -0.7‰). Faeces were also depleted in (13)C ((13)Δ =1.7‰). Influences of feeding environment (stall vs. pasture) and herbage quality were minor (<0.4‰). A review of literature data shows large variation between studies. We consider that the present results are superior, as they are based on a much larger data set regarding the number of cows and milkings (total n = 256) with greater detail in analyses of diet and milk products. Also, the study covered both stall- and pasture-feeding scenarios in realistic settings with long periods of equilibration. This is the first comprehensive analysis of (13)C discrimination between diet and all main milk components (as well as faeces). Thus, the results will improve the use of stable isotope analyses in regard to authenticity testing and proof of origin.

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“…The largest and fastest increase in δ 13 C was seen for lactose, pointing at the importance of dietary carbon for milk lactose synthesis. Although glucose as a precursor for lactose is barely absorbed by the intestine in ruminants, and ruminants have to synthesise glucoses mainly in the liver with propionate as the dominant substrate [6,29,30], δ 13 C in lactose was close to the maximal value two days after start of C 4 diet feeding. It cannot be excluded that some glucose may have originated from starch digestion in the intestine, because corn starch is less fermented in the rumen than starch from barley or wheat [31,32].…”

Section: C Data Of Milk Components and With Respect To Different Mmentioning

confidence: 87%

“…There is possibly some variation in the use of dietary amino acids and mobilised amino acids from the body protein for milk protein synthesis between HOL and F 2 Charolais × Holstein crosses cows that point at a genetic influence on the utilisation of dietary nutrients for milk protein synthesis. In addition, the greater increase in δ 13 C max for casein in F 2 Charolais × Holstein crosses compared with HOL cows might be due to different rumen fermentations and variations in microbial protein formation that might have influenced protein digestion and availability of amino acids for lactation [6,29].…”

Section: C Data Of Milk Components and With Respect To Different Mmentioning

confidence: 91%

Milk production and nutrient partitioning as measured by¹³C enrichment of milk components during C₃and C₄plant feeding in purebred Holstein and in Charolais × Holstein F₂crossbred cows

Hillal

Voigt

Metges

et al. 2014

Isotopes in Environmental and Health Studies

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Nutrient partitioning was investigated in cows with different genetic merits for milk production by measuring (13)C/(12)C ratios (reported by delta values δ(13)C) in milk components in response to C3 (grass silage) and C4 diets (corn silage). We hypothesised that changes of δ(13)C in milk differ between Holstein (HOL; high milk production) and Charolais × Holstein cows with medium (CHM) and low (CHL) milk production. Changes of δ(13)C (Δδ(13)C) in milk components were estimated by calculating differences of δ(13)C due to switch from C3 to C4 feeding. After switch to C4 feeding, Δδ(13)C of lactose was greater in HOL than in CHL. Immediate Δδ(13)C of milk fat was the lowest in CHL. The maximal Δδ(13)C of casein was the lowest in HOL. The proportion of carbon in milk derived from diet increased with milk yield, indicating the main impact of the milk production level, but minor impact of breed, on nutrient partitioning towards the mammary gland.

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Effect of energy metabolism on 13C/12C-ratios in milk fat and lactose of cows

Cited by 3 publications

References 13 publications

Preparation of Naturally ¹³C-Rich Free Fatty Acids (FFA) from Corn Oil and their Application in Metabolic Studies of Lactating Cows

Preparation of Naturally ¹³C-Rich Free Fatty Acids (FFA) from Corn Oil and their Application in Metabolic Studies of Lactating Cows

¹³C discrimination between diet, faeces, milk and milk components

Milk production and nutrient partitioning as measured by¹³C enrichment of milk components during C₃and C₄plant feeding in purebred Holstein and in Charolais × Holstein F₂crossbred cows

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Effect of energy metabolism on 13C/12C-ratios in milk fat and lactose of cows

Cited by 3 publications

References 13 publications

Preparation of Naturally 13C-Rich Free Fatty Acids (FFA) from Corn Oil and their Application in Metabolic Studies of Lactating Cows

Preparation of Naturally 13C-Rich Free Fatty Acids (FFA) from Corn Oil and their Application in Metabolic Studies of Lactating Cows

13C discrimination between diet, faeces, milk and milk components

Milk production and nutrient partitioning as measured by13C enrichment of milk components during C3and C4plant feeding in purebred Holstein and in Charolais × Holstein F2crossbred cows

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Preparation of Naturally ¹³C-Rich Free Fatty Acids (FFA) from Corn Oil and their Application in Metabolic Studies of Lactating Cows

Preparation of Naturally ¹³C-Rich Free Fatty Acids (FFA) from Corn Oil and their Application in Metabolic Studies of Lactating Cows

¹³C discrimination between diet, faeces, milk and milk components

Milk production and nutrient partitioning as measured by¹³C enrichment of milk components during C₃and C₄plant feeding in purebred Holstein and in Charolais × Holstein F₂crossbred cows