The difference in transfer of all-rac-α-tocopherol stereo-isomers to milk from cows and the effect on its oxidative stability

Slots, Tina; Skibsted, Leif H.; Nielsen, Jacob Holm

doi:10.1016/j.idairyj.2006.09.010

Cited by 20 publications

(26 citation statements)

References 21 publications

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“…In contrast, Slots et al (2007) suggested that milk with a high a-tocopherol concentration was more susceptible to oxidation than milk with low a-tocopherol.…”

Section: Vitamin E Supplementation and Milk Qualitymentioning

confidence: 91%

Reevaluation of vitamin E supplementation of dairy cows: bioavailability, animal health and milk quality

Politis

2012

Animal

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Although vitamin E has been known as an essential nutrient for almost 80 years, we are far from a complete understanding of all the aspects related to bioavailability and its effects on health and milk quality in dairy cows. Vitamin E is a generic descriptor for two families of lipid-soluble compounds, the tocopherols and the tocotrienols, of which a-tocopherol has the highest biological activity. Commercially available a-tocopherol supplements for dairy cows contain either the natural RRR form or the synthetic (all-rac) form, which contains all the eight possible stereoisomers (four possessing the 2R and four possessing the 2S configuration) in equimolar amounts. Recent data clearly suggest that an almost complete discrimination against the 2S isomers occurs in dairy cows. Thus, 1 g of the all-rac form is essentially equivalent to 0.5 g of the RRR form. With respect to the effect of vitamin E supplementation of dairy cows on health and milk quality, the majority of published studies suggests that vitamin E supplementation at the level 1000 to 4000 IU/cow per day during the dry period reduces both the frequency of intramammary infection and that of clinical mastitis and improves milk quality, as shown by a reduction in the levels of somatic cell count (SCC)/ml in milk, decreased plasmin activity and increased oxidative stability of milk. However, a recent study from the Netherlands suggested that vitamin E supplementation at the 3000 IU/cow per day level during the dry period when combined with high levels of plasma vitamin E at dry-off (.14.5 mmol/l) increases the incidence of mastitis. Data from previously unpublished survey studies and those from published vitamin E feeding trials, in which high levels of blood vitamin E were observed, were reanalyzed. All farms selected for the analysis implemented oral administration of vitamin E at the 3000 IU/cow per day level throughout or during the late dry period (4 weeks before the expected day of parturition). Dairy cows were divided into three groups, depending on blood a-tocopherol levels at dry-off: high (.6.25 mg/ml), medium (between 6.25 and 4.25 mg/ml) and low (,4.25 mg/ml). Data indicate that there were no differences in the incidence of mastitis and in the level of SCC/ml of milk between the three groups. Thus, supplementation of 3000 IU vitamin E/cow per day in the late dry period remains recommended because it is generally associated with decreased risk of mastitis. Conditional or opposite effects have not been repeated and require further research before changing recommendations for vitamin E supplementation.

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“…In contrast, Slots et al (2007) suggested that milk with a high a-tocopherol concentration was more susceptible to oxidation than milk with low a-tocopherol.…”

Section: Vitamin E Supplementation and Milk Qualitymentioning

confidence: 91%

Reevaluation of vitamin E supplementation of dairy cows: bioavailability, animal health and milk quality

Politis

2012

Animal

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“…Extraction, separation, and quantification of tocopherols from the milk were performed as described by Havemose et al (2004) with modifications as explained in Slots et al (2007). Milk (2.00 mL) and acetic acid in ethanol [2.00 mL 1% (wt/ vol)] were mixed for 10 s. Saturated potassium hydroxide in water (0.30 mL) was added.…”

Section: Extraction and Quantification Methodsmentioning

confidence: 99%

“…Derivatization and isomeric distribution of α-tocopherol stereoisomers to the corresponding α-tocopheryl methyl ether stereoisomers were performed as described by Riss et al (1994) with modification as explained in Slots et al (2007). The extracted tocopherol mixture (2.00 mL) was evaporated under nitrogen to dryness and dissolved in n-heptane (500 μL).…”

Section: Isomeric Distribution Of Extracted Tocopherol Based On Derivmentioning

confidence: 99%

“…Extraction from methylation and detection of fatty acids in milk was performed as described by Havemose et al (2004) and by Slots et al (2007) with modification. Milk fat was extracted from milk by adding methanol (2.00 mL) and chloroform (4.00 mL) to milk (2.00 mL).…”

Section: Isomeric Distribution Of Extracted Tocopherol Based On Derivmentioning

confidence: 99%

“…In milk, the concentration of α-tocopherol and carote-noids as antioxidants is believed to be important for the oxidative stability; tocopherol and β-carotene scavenge lipid peroxy radicals and quench singlet oxygen. However, there are contradictive results in this field because earlier work shows prooxidative behavior of α-tocopherol, when no coantioxidant, such as coenzyme Q, is present (Thomas et al, 1996), or when a high concentration of unsaturated fat and α-tocopherol is present in milk (Slots et al, 2007). High concentrations of α-tocopherol and β-carotene in milk can be obtained by a high proportion of pasture or grass clover silage in the feed of dairy cows (Havemose et al, 2004) because these forage types are high in antioxidants (Lynch et al, 2001).…”

Section: Introductionmentioning

confidence: 99%

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Potentials to differentiate milk composition by different feeding strategies

Slots

Butler

Leifert

et al. 2009

Journal of Dairy Science

108

125

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To investigate the effect of the dietary intake of the cow on milk composition, bulk-tank milk was collected on 5 occasions from conventional (n = 15) and organic (n = 10) farms in Denmark and on 4 occasions from low-input nonorganic farms in the United Kingdom, along with management and production parameters. Production of milk based on feeding a high intake of cereals, pasture, and grass silage resulted in milk with a high concentration of α-linolenic acid (9.4 ± 0.2 mg/ kg of fatty acids), polyunsaturated fatty acids (3.66 ± 0.07 mg/kg of fatty acids), and natural stereoisomer of α-tocopherol (RRR-α-tocopherol, 18.6 ± 0.5 mg/kg of milk fat). A milk production system using a high proportion of maize silage, by-products, and commercial concentrate mix was associated with milk with high concentrations of linoleic acid (LA; 19.7 ± 0.4 g/kg of fatty acids), monounsaturated fatty acids (27.5 ± 0.3 mg/kg of fatty acids), and a high ratio between LA and α-linolenic acid (4.7 ± 0.2). Comparing these 2 production systems with a very extensive nonorganic milk production system relying on pasture as almost the sole feed (95 ± 4% dry matter intake), it was found that the concentrations of conjugated LA (cis-9,trans-11; 17.5 ± 0.7 g/kg of fatty acids), trans-11-vaccenic acid (37 ± 2 g/kg of fatty acids), and monounsaturated fatty acids (30.4 ± 0.6 g/kg of fatty acids) were higher in the extensively produced milk together with the concentration of antioxidants; total α-tocopherol (32.0 ± 0.8 mg/ kg of milk fat), RRR-α-tocopherol (30.2 ± 0.8 mg/kg of milk fat), and β-carotene (9.3 ± 0.5 mg/kg of milk fat) compared with the organic and conventional milk. Moreover, the concentration of LA (9.2 ± 0.7 g/kg of fatty acids) in milk from the extensive milk production system was found to approach the recommended unity ratio between n-6 and n-3, although extensive milk production also resulted in a lower daily milk yield.

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A critical review of methodologies used in determination of relative bio-availability ratio ofRRR-α-tocopheryl acetate andall-rac-α-tocopheryl acetate

Dersjant-Li¹,

Peisker²

2010

J. Sci. Food Agric.

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Bio-availability of different alpha-tocopherol forms in livestock animals is measured by the increase in plasma or tissue concentrations of alpha-tocopherol after oral administration. It is generally accepted that RRR-alpha-tocopheryl acetate (natural source vitamin E derived from vegetable oil) has a higher bio-availability compared to all-rac-alpha-tocopheryl acetate (synthetic vitamin E, i.e. alpha-tocopherol produced by chemical synthesis). However, different bio-availability ratios have been reported in the literature. The major reason for conflicting results in literature studies was the inability to separate the proportion of alpha-tocopherol originating from test materials, from the proportion of alpha-tocopherol originating from basal dietary ingredients and pre-feeding. This causes significant variability. For bio-availability determination, a baseline or control treatment is essential. The estimation of bio-availability without correction for basal vitamin E status will lead to incorrect interpretation of the results. When using proper methodologies, it is possible to correct for the impact of alpha-tocopherol intake from basal ingredients and alpha-tocopherol originating from pre-feeding, therefore yielding results reflecting the true relative bio-availability of different alpha-tocopherol substances. When reviewing literature data a critical evaluation of the method used in determination of relative bio-availability is recommended.

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The difference in transfer of all-rac-α-tocopherol stereo-isomers to milk from cows and the effect on its oxidative stability

Cited by 20 publications

References 21 publications

Reevaluation of vitamin E supplementation of dairy cows: bioavailability, animal health and milk quality

Reevaluation of vitamin E supplementation of dairy cows: bioavailability, animal health and milk quality

Potentials to differentiate milk composition by different feeding strategies

A critical review of methodologies used in determination of relative bio-availability ratio ofRRR-α-tocopheryl acetate andall-rac-α-tocopheryl acetate

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