Α-tocopherol In Milk Research Articles

Influence of season and pasture feeding on the content of α-tocopherol and β-carotene in milk from Holstein, Brown Swiss and Modicana cows in Sicily

It has been shown that several factors such as feed source and breed might influence milk fat-soluble antioxidants (AOs). This study investigated pasture feeding effects and dairy cattle breed on the content of α-tocopherol and β-carotene in cows' milk by monitoring two grazing seasons (spring and fall) as well as a summer no-pasture season. Four dairy farms located in Sicily were selected: two with both Holstein and Brown Swiss cows and two with only a Modicana (M) local breed cows. Bulk milk samples of each breed per farm were collected. Milk α-tocopherol and β-carotene were highest during spring (16.2 and 9.7 μg.g−1 of fat, respectively), lowest during fall (11.2 and 0.8 μg.g−1 of fat, respectively) and intermediate during summer (13.3 and 2.5 μg.g−1 of fat, respectively). These results indicate that grazing pasture season has an important impact on milk fat-soluble antioxidant content. In particular, higher milk AO levels in spring compared to fall might be attributed to several factors such as differences in the quality and composition of pasture, differences in pasture intake and even the climate. Breed effect on milk AO contents was not so pronounced. Milk β-carotene levels did not differ significantly among breeds. Saturation of milk β-carotene may explain similar vitamin levels among breeds in spring despite different pasture intakes. It was interesting that significant levels of α-tocopherol were detected in milk from M cows during summer. The latter effect could be masked by the considerably higher pasture intake of M in spring compared to the other two breeds.

Effect of Feeding Intensity and Milking System on Nutritionally Relevant Milk Components in Dairy Farming Systems in the North East of England

There is increasing concern that the intensification of dairy production reduces the concentrations of nutritionally desirable compounds in milk. This study therefore compared important quality parameters (protein and fatty acid profiles; α-tocopherol and carotenoid concentrations) in milk from four dairy systems with contrasting production intensities (in terms of feeding regimens and milking systems). The concentrations of several nutritionally desirable compounds (β-lactoglobulin, omega-3 fatty acids, omega-3/omega-6 ratio, conjugated linoleic acid c9t11, and/or carotenoids) decreased with increasing feeding intensity (organic outdoor ≥ conventional outdoor ≥ conventional indoors). Milking system intensification (use of robotic milking parlors) had a more limited effect on milk composition, but increased mastitis incidence. Multivariate analyses indicated that differences in milk quality were mainly linked to contrasting feeding regimens and that milking system and breed choice also contributed to differences in milk composition between production systems.

Effect of legume–grass silages and α-tocopherol supplementation on fatty acid composition and α-tocopherol, β-carotene and retinol concentrations in organically produced bovine milk

Two feeding experiments were performed to study the effects of silage botanical composition, regrowth interval and α-tocopherol supplementation on the fatty acid (FA) composition and α-tocopherol, β-carotene and retinol concentrations of milk. In Exp. 1, 24 Swedish Red dairy cows were fed two- or three-cut red clover–grass silages (R2 and R3, respectively) or two-cut birdsfoot trefoil–grass silage (B2). In Exp. 2, 16 Norwegian Red dairy cows were fed short-term ley silage with red clover (S3) or long-term ley silage with white clover (L3) in combination with the supplementation of RRR-α-tocopheryl acetate (1600mg/day). The FA proportions in the milk and the recoveries of C18:2n-6 and C18:3n-3 were higher on the red clover diets R2 and S3 than on B2 and L3, respectively, and the n-6/n-3 FA ratio was also higher on the red clover diets. Shorter regrowth interval increased both the concentrations of FA in silage and the proportions of unsaturated FA in milk. Intakes of α-tocopherol, β-carotene and lutein were higher on B2 than on R2 due to higher silage intake on B2. However, the highest intake was seen on diet R3 due to the higher concentrations in the silage mixture. In Exp. 2, intakes of α-tocopherol, β-carotene and lutein were higher on L3. However, not all of these differences affected the milk, since the only significant differences related to silage diet in the two experiments were a higher milk α-tocopherol concentration on L3 than on S3 and a slightly lower β-carotene concentration on B2 than on R2. Supplementation with α-tocopherol increased milk α-tocopherol concentrations from 0.77 to 1.05 and from 1.07 to 1.24mg/kg milk for S3 and L3, respectively, but did not affect milk FA composition.A higher concentration of antioxidants in the feed could be beneficial as a larger proportion of the animal's vitamin requirements would be met by the forage and the need for supplementation might decrease.

Effects of green tea catechin on the lipid oxidation, volatile compound formation, and losses of retinol and α-tocopherol in whole milk during light illumination as compared with ascorbic acid

Effects of green tea catechin (GTC, catechin content 61.4%) on the formations of hydroperoxide, malonaldehyde, and volatile compounds, and losses of retinol and tocopherol in milk during light illumination were studied. GTC showed surprisingly high protective activity of milk photooxidation, in a dose dependent manner. GTC at 25 ppm exerted 82.1 and 75.0% inhibitions of hydroperoxide and malonaldehyde formation during 30 h light illumination, respectively. GTC at 25 ppm exerted 88.7 and 94.3% inhibition of hexanal and heptanal formation in milk during 30 h light illumination, respectively. The 25 ppm GTC greatly suppressed the losses of retinol and α-tocopherol, showing 53.6 and 58.7% protections of their losses in milk after 12 h light illumination, respectively. The protective activity of GTC was at least 4 times higher than ascorbic acid. The inhibitory activities of GTC and ascorbic acid against the photooxidation of milk were in consistent with their singlet oxygen quenching abilities.

Effects of RRR-α-tocopheryl acetate supplementation during the transition period on vitamin status in blood and milk of organic dairy cows during lactation

This study investigated effects of daily supplementation with RRR-α-tocopheryl acetate, during the transition period around calving, on concentrations of α-tocopherol in plasma and milk from prepartum to mid-late lactation of dairy cows. Retinol and β-carotene contents also were measured. The study included 2 experiments, where all cows were fed 100% organic diets, with high proportions of grass-legume forage. The experimental design was a randomised complete block. In experiment 1, the basal diet contained 70 and 60IU of RRR-α-tocopherol/kg DM (dry period and lactation, respectively) and was supplemented with 0 (C) or 2400 (E) IU of RRR-α-tocopheryl acetate from 3weeks before to 3weeks post calving (PC). In experiment 2, the basal diet contained 29IU of RRR-α-tocopherol/kg DM plus 31 (dry) or 20 (lactating) IU of synthetic vitamin E/kg DM and was supplemented with 0 (C) or 2400 (E) IU of RRR-α-tocopheryl acetate from 3weeks before to 3weeks PC. Synthetic vitamins A and D also were supplemented in experiment 2. Blood samples were collected at 3weeks before expected calving, at calving, at 3weeks PC and between 5 and 7months PC, while milk samples were collected from colostrum, at 4days PC, at 3weeks PC and between 5 and 7months PC. In both experiments, E cows tended to have higher plasma concentrations of α-tocopherol at calving than C cows. At 3weeks PC, concentrations in plasma were 34% and 22% higher in E cows than in C cows in experiment 1 and 2, respectively (P<0.05). The treatments resulted in similar vitamin concentrations in milk in experiment 1. In experiment 2, the basal diet was low in RRR-α-tocopherol, and E cows had 61%, 207% and 181% higher concentrations of α-tocopherol than C cows in the milk from colostrum, 4days PC and 3weeks PC, respectively (P<0.05). There were no differences between treatments in either plasma or milk later in lactation. High concentrations of α-tocopherol and β-carotene in forage decreased the effect of the E treatment. However, as concentrations of α-tocopherol and β-carotene in forage are difficult to predict vitamin supplementation is recommended, especially around calving. Retinol concentrations in plasma in experiment 1 were generally low (< 0.25mg/l during the transition period), indicating that vitamin A supplementation also is necessary, especially during the transition period.

Effects of oral supplementation with β‐carotene on concentrations of β‐carotene, vitamin A and α‐tocopherol in plasma, colostrum and milk of mares and plasma of their foals and on fertility in mares

In this study, effects of oral β-carotene supplementation to mares (β-carotene group: 1000 mg/day, n = 15; control group: n = 15) from 2 weeks before foaling until 6 weeks thereafter on concentrations of β-carotene, vitamin A and α-tocopherol in plasma, colostrum and milk and plasma of their foals were determined. In addition, effects on fertility were studied. Beta-carotene concentrations increased in plasma and colostrum of β-carotene-supplemented mares compared to control mares (p < 0.05). In mares of both groups, β-carotene concentrations were higher in colostrum than in milk (p < 0.05). In foals, β-carotene concentrations increased with colostrum uptake and were higher in foals born to supplemented mares (p < 0.05; control group: 0.0003 ± 0.0002 μg/ml on day 0, 0.008 ± 0.0023 μg/ml on day 1; β-carotene group: 0.0005 ± 0.0003 μg/ml on day 0, 0.048 ± 0.018 μg/ml on day 1). Concentrations of vitamin A and α-tocopherol were higher in colostrum than in milk (p < 0.05) but did not differ between groups. Concentration of α-tocopherol in plasma of mares decreased over time and in foals, increased markedly within 4 days after birth. All but one mare (control group) showed oestrus within 2 weeks post-partum. Occurrence of oestrus did not differ between groups. More mares of the control group (7/7 vs. 5/12 in the β-carotene group) became pregnant after being bred in first post-partum oestrus (p < 0.05). In conclusion, β-carotene supplementation to mares increased β-carotene concentrations in plasma, colostrum and milk of mares and plasma of their foals but had no positive effects on fertility.

Increasing pasture intakes enhances polyunsaturated fatty acids and lipophilic antioxidants in plasma and milk of dairy cows fed total mix ration

Polyunsaturated fatty acids and lipo-soluble vitamins in the milk are considered as neutraceutical compounds due to their beneficial effects on human health. The aim of the present study was to evaluate the changes in fatty acid composition and fat-soluble antioxidant content in plasma and milk from cows fed with different dietary proportions from pasture. Cows from a farm in the Hyblean mountain region in Italy were randomly divided into three groups (12 animals per group): CTRL fed only a total mix ration (TMR); 30P fed a TMR supplemented with 30% dry matter (DM) from pasture and 70P fed a TMR supplemented with 70% DM of pasture. Blood and milk samples were collected, stored and analysed for their content of fatty acids and fat-soluble antioxidants. Fatty acid profiles were significantly modified by different diets. CLA, vaccenic acid (VA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) significantly (P < 0.05) increased in plasma as a function of the proportion of pasture added to the diet. In agreement with these data, a progressively significant (P < 0.05) increase in concentrations of VA, CLA and EPA was observed in the milk. Such changes in fatty acid composition were accompanied by a concomitant increase in the concentrations of α-tocopherol and β-carotene in both plasma and milk. The increase in EPA, DHA and CLA, β-carotene and α-tocopherol in plasma may not only have a beneficial impact for milk and meat quality, but may also result in an increased protection against inflammatory events.

Administration of RRR-α-tocopherol to pregnant mares stimulates maternal IgG and IgM production in colostrum and enhances vitamin E and IgM status in foals

This study assessed the effect of a vitamin E supplement given to pregnant mares on immunoglobulins (Ig) levels in foals. In addition, the fatty acid (FA) content and composition of the mares' milk was assessed. Milk α-tocopherol concentrations were compared between pregnant Danish Warmblood mares (n = 17) given a daily oral supplement of 2500 international units (IU) RRR-α-tocopherol in the last 4 weeks of pregnancy and a group of unsupplemented mares (n = 17) receiving 170-320 IU vitamin E daily originating from the feed. Milk α-tocopherol was higher in supplemented mares (36.7, 12.4 and 9.8 μmol/l respectively) in relation to control mares (13.1, 6.4 and 5.8 μmol/l on days 1, 2 and 3 respectively; p < 0.001). Milk IgG was higher on days 2 and 3 post-partum (PP) in supplemented mares (1.03 and 0.73 mg/ml respectively) in relation to control mares (0.79 and 0.56 mg/ml respectively; p < 0.05). Milk IgM was higher on days 2 and 3 post-partum (PP) in supplemented mares (0.19 and 0.17 mg/ml) in relation to control mares (0.13 and 0.11 mg/ml respectively; p < 0.05). Plasma α-tocopherol in foals was higher from supplemented mares on days 1, 2 and 3 (5.7, 14.8 and 19.2 μmol/l respectively) in relation to foals from control mares (3.6, 6.1 and 7.6 respectively; p < 0.001). Foal plasma IgM was higher from supplemented mares on day 3 (0.50 mg/ml) in relation to foals from control mares (0.32 mg/ml; p < 0.001). The total FA content in milk was highest on day 1 (21.6 g FA/kg milk) in relation to days 2 and 3 (13.6 and 13.5 g FA/kg milk respectively; p < 0.001). In conclusion, a daily oral supplement of 2500 IU RRR-α-tocopherol increased α-tocopherol content in mare milk and foal plasma, IgG and IgM in mare milk and IgM in foal plasma.

Breast milk tocopherol content during the first six months in exclusively breastfeeding Greek women

To determine tocopherol and fat content of Greek mother's milk during the first 6 months of exclusive breastfeeding and correlate with maternal diet characteristics. Milk samples and dietary records were obtained by mothers at 1st (n = 64), 3rd (n = 39) and 6th (n = 23) month postpartum. Milk tocopherol content was determined by high-performance liquid chromatography method (HPLC) and fat content by the crematocrit method. Milk's α-tocopherol content at 1st, 3rd and 6th month postpartum was 8.3 ± 3.4, 8.1 ± 4.2 and 8.5 ± 4.7 μmol/L, while total tocopherol values were 8.9 ± 3.6, 8.7 ± 4.6 and 9.5 ± 5.6 μmol/L, respectively, and were closely related to milk's fat content. No significant differences were observed for α- and total tocopherol content in breast milk among the three time points. Maternal vitamin E dietary intake was 7.2 ± 3.7, 6.8 ± 3.5 and 10.9 ± 5.2 mg/day at 1st, 3rd and 6th month postpartum, respectively. Though vitamin E dietary intake was less than the recommended one, vitamin E content in breast milk was considered sufficient for infant needs. Milk tocopherol content was found to be associated only with mothers' total fat and saturated fat dietary intake. This study is among few in literature to determine tocopherol content of breast milk in European women and detect dietary factors that may influence its values. The only maternal dietary characteristic to affect breast milk tocopherol content was mothers' total fat intake, while tocopherol intake seems to have no effect.

Antioxidant capacity of human milk and its association with vitamins A and E and fatty acid composition

Aim:The antioxidant capacity of human milk reflects the presence and activity of multiple components, which prevent oxidative rancidity. The aim of this study was to use the Oxygen Radical Absorbance Capacity assay to assess human milk antioxidant capacity and find correlations with milk components.Methods:Milk samples collected from 60 breastfeeding women at 1 month postpartum were assayed for antioxidant capacity, vitamins E and A, and fatty acids. Potential statistical relationships of concentrations of vitamins A and E and polyunsaturated fatty acids on the antioxidant capacity of human milk were determined.Results:Human milk antioxidant capacity was positively attributed to α-tocopherol concentration (ρ < 0.05). The vitamin A concentration did not significantly contribute to milk antioxidant capacity, but was correlated to milk α-tocopherol concentration (r=0.587; ρ < 0.001). There was no evidence of an inverse relationship between polyunsaturated fatty acids concentration and the antioxidant capacity value of milk.Conclusion:This study shows that α-tocopherol is an important contributor to the oxidative stability of human milk. Moreover, there was no evidence obtained to show that women who have high levels of milk polyunsaturated fatty acids are predisposed to lower milk antioxidant capacity.

Quantitative Determination of Underivatized α-Tocopherol in Cow Milk, Vitamin and Multivitamin Drugs by GC-FID

A simple and rapid method for direct determination of α-tocopherol (α-T, vitamin E) in pharmaceutical preparations (vitamin and multivitamin tablets) and cow milk obtained from different villages of Erzurum in Turkey was developed and validated by GC-FID. Separation of underivatized α-T in pure substance, milk samples, vitamin and multivitamin tablets was performed in about 8.4 min, using an HP-5 capillary column. The range of quantification for the GC-FID was 1–30 μg mL−1. Within-day and between-day precision (RSD %) were less than 8.5%, and accuracy (relative error) was less than 11.0% (n = 6). LOQ and LOD values were found to be 0.35 and 0.30 μg mL−1, respectively. The developed method was applied directly and easily to the analysis of α-T in vitamin and multivitamin preparations and cow milk. RSD values were found to be 6.59% (Grandpherol soft gelatine capsule: 200 I.U.), 0.59% (Megadyn film tablet: 10 mg) and 1.54% (Supradyn drage: 10 I.U.). The developed method was also applied to cow milk samples and mean values of α-T content was found 2.99 μg mL−1 in cow milk samples. This developed and validated GC–FID method, in conjunction with other methods, could be successfully applied for routine laboratory because of its simplicity, rapidity, sensitivity, precision and accuracy.

Ultra-High-Pressure Liquid Chromatographic method for the analysis of tocopherols in human colostrum and milk

A rapid, highly sensitive and direct Ultra-High-Pressure Liquid Chromatographic method was developed and validated for quantifying δ-, β + γ-, and α-tocopherol in human colostrum and milk. Two reversed-phase chromatographic columns and two detectors (Fluorescence Detector or FD and Photodiode Detector Array or PDA) were used and both methods were independently validated. Two internal standards were selected according to the detector used. Recoveries ranged from 96.71% to 103.55% and the relative standard deviations for the within-day precision were below 6% (PDA) and 3% (FD). Both approaches enabled to achieve low detection limits, on the order of ng (PDA) or pg (FD). Only 300 μL of sample and a chromatographic run of less than 1.6 min were enough to efficiently quantify the isomers in the colostrum and milk of Spanish women.

Relative bioavailability of all-rac and RRR vitamin E based on neutrophil function and total α-tocopherol and isomer concentrations in periparturient dairy cows and their calves

The objective of this experiment was to determine whether source of supplemental α-tocopherol fed to periparturient dairy cows affects neutrophil function and vitamin E status of the cow and the neonatal calf. Starting 14 d before anticipated calving and continuing until 14 d post-parturition, cows were fed diets with no supplemental vitamin E or with 2,500IU/d of vitamin E from all-rac α-tocopheryl acetate or RRR α-tocopheryl acetate. All-rac α-tocopherol contains equimolar amounts of all 8 stereoisomers, whereas the RRR contains only the RRR isomer. Concentrations of α-tocopherol in cow plasma, colostrum, milk, and blood neutrophils were greatest for the RRR treatment, intermediate for all-rac, and lowest for cows fed no supplemental vitamin E. The concentration of α-tocopherol in plasma of newborn calves was very low and not affected by treatment but after 6 feedings of their dam's colostrum or milk, concentrations in calf plasma followed the same treatment pattern as cow plasma. The number of bacteria phagocytized was greater by neutrophils from cows fed all-rac vitamin E than for the other 2 treatments, which resulted in a greater number of bacteria being killed. For cows fed all-rac vitamin E, the RRR isomer comprised about 20% of the α-tocopherol consumed but approximately 60% of the α-tocopherol in plasma and milk. This enrichment was caused mostly by an almost complete discrimination against the 2S isomers. Because all-rac α-tocopherol is 50% 2S isomers, these data suggest that 1g of all-rac tocopheryl acetate is equivalent to 0.5g of RRR tocopheryl acetate.

Effect of Daytime Grazing of Fresh Grass without Supplemental Feed on Serum and Milk α-Tocopherol Concentrations of Holstein Dairy Cows

Nakamura, Y., Shiga, A., Akasaka, S. and Gotoh, T. 2007. Effect of daytime grazing of fresh grass without supplemental feed on serum and milk α-tocopherol concentrations of Holstein dairy cows. J. Appl. Anim. Res., 32: 119–124. The effect of switching 5 Holstein dairy cows from concentrate-fed to roughage-fed conditions without supplemental feed for seven weeks on serum parameters and milk chemical composition in morning and afternoon milk samples was investigated. BW was not affected and blood hematocrit and total protein, glucose and triglyceride concentrations varied within normal values throughout the experiment. During day grazing period, serum non-esterified fatty acid (NEFA), milk somatic cell counts (SCC), total solids, lipids and milk and serum α-tocopherol values increased, whereas, those of milk yield, milk protein, lactose and solids-non-fat decreased. For diurnal changes, NEFA concentrations were lower, whereas, SCC, milk lipid and milk α-tocopherol concentrations were higher in the afternoon. Changes in milk chemical composition, when cows were switched from concentrate-fed to roughage-fed conditions including daytime grazing, were related to the chemical composition of the feeds consumed.

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

Experiments were conducted to study the effect of all-rac-α-tocopheryl acetate supplementation of the diet of dairy cows on the oxidative stability of milk. In experiment I the cows’ feed was supplemented with 2600 IU per day per cow and in experiment II with 3400 IU and high amounts of unsaturated fat to get the milk more susceptible to oxidation. The content of α-tocopherol in milk was determined before and after supplementation, and the percentage increase of α-tocopherol in the milk in the two experiments was 37% and 29%, respectively. The native stereo-isomer ( RRR-α-tocopherol) made up 84.3% (experiment I) and 88.8% (experiment II) of the isomers, indicating that transfer of the synthetic stereo-isomers to the milk was low. The milk was further exposed to fluorescent light or added copper. Milk with a high content of unsaturated fatty acids and high concentrations of α-tocopherols was more susceptible to oxidation than the milk with low α-tocopherol content.

Enhancing α-Tocopherol and Linoleic Acid in Ewe's Milk by Feeding Emulsified Sunflower Oil and dl-α-Tocopheryl Acetate in a Chemically Treated Protein Matrix

Chemically treated dietary supplements (CTDS) were prepared with defatted soy flour, sunflower oil, dl-alpha-tocopheryl acetate (TA), and 2,3-butanedione (a generally recognized as safe chemical), and the effects on alpha-tocopherol (VE) concentration and fatty acid profile in ewe's milk were estimated. Ewes fed control diet (CD) had the lowest levels of milk VE (0.66 microg/mL) and serum VE (1.59 microg/mL). Feeding ewes the CD plus 500 IU of TA increased milk and serum VE by 30 and 70%, respectively, compared to ewes fed the CD. The CTDS-fed ewes showed further increased milk and serum VE levels by 40 and 32%, respectively, over those in ewes fed the CD plus 500 IU of TA. Feeding ewes CTDS did not affect milk fat content (3.13%) but altered the fatty acid composition by decreasing the levels of hypercholesteremic fatty acids, while increasing the content of linoleic acid (8.5%). Inclusion of CTDS in ruminant diets might produce nutritionally enhanced milk products.

Influence of supplementation of all-rac-α-tocopheryl acetate preweaning and vitamin C postweaning on α-tocopherol and immune responses of piglets1

This study was designed to test whether dietary maternal supplementation of all-rac-alpha-tocopheryl acetate during lactation and dietary vitamin C supplementation after weaning could increase the alpha-tocopherol status pre- and postweaning and the immune responses of piglets postweaning. The experiment involved 12 crossbred sows that were fed increasing levels of all-rac-alpha-tocopheryl (70, 150, and 250 IU/kg, as-fed basis) during lactation. After weaning (d 28 of age), litters were divided into two groups that were supplemented with or without vitamin C (500 mg/kg of feed, as-fed basis). Milk and blood samples were obtained from the sows during lactation. Pigs were bled at 4, 16, 28, 35, 42, and 49 d of age. Liver, heart, muscle, and s.c. adipose tissues were collected (on 28, 35, 42, and 49 d of age) and analyzed for alpha-tocopherol. On the same days, alveolar macrophages of the lungs were collected, and analyzed for the concentration of alpha-tocopherol and its stereoisomer composition, fatty acid composition, and release of prostaglandin E2, leukotriene B4, and thromboxane B2. Increasing dietary all-rac-alpha-tocopheryl acetate concentration increased the concentration of alpha-tocopherol in plasma (P = 0.02) and milk (P = 0.007) of sows, and the sow milk concentrations of alpha-tocopherol and vitamin A were greater on d 2 of lactation than later on during lactation. The plasma concentration of alpha-tocopherol in piglets decreased from d 4 to later on during suckling (P < 0.001) and again as the postweaning period progressed (P < 0.001). When lipid-standardized, plasma alpha-tocopherol was increased in piglets of sows fed 250 IU of all-rac-alpha-tocopheryl acetate compared with other sow-groups (P = 0.005). At 28 d of age, alpha-tocopherol concentrations in tissues were increased with supplementation of the high dietary all-rac-alpha-tocopheryl acetate levels to the sows; however, after weaning, a decrease in alpha-tocopherol concentration in most tissues (except liver) was observed, but the decrease tended to be less in the muscle (P = 0.099) and adipose tissue (P = 0.11) of piglets suckling sows fed 150 and 250 IU of all-rac-alpha-tocopheryl acetate. Vitamin C supplementation after weaning increased liver alpha-tocopherol (P = 0.01) and serum immunoglobulin M concentration (P = 0.04), and vitamin C supplementation increased the proportion of the RRR-alpha-tocopherol (P = 0.03) at the expense of the RRS-stereoisomer form (P = 0.05) of alpha-tocopherol in alveolar macrophages of the piglets. In conclusion, this study on maternal all-rac-alpha-tocopheryl acetate and postweaning vitamin C supplementation suggests a nutritional strategy for increasing alpha-tocopherol status and immune responses of weaned piglets.

A study on the causes for the elevated n−3 fatty acids in cows' milk of alpine origin

The influence of grass-only diets either from rye-grass-dominated lowland pastures (400 m above sea level) or botanically diverse alpine pastures (2000 m) on the FA profile of milk was investigated using three groups of six Brown Swiss cows each. Two groups were fed grass-only on pasture (P) or freshly harvested in barn (B), both for two experimental periods in the lowlands and, consecutively, two periods on the alp. Group C served as the control, receiving a silage-concentrate diet and permanently staying in the lowlands. Effects of vegetation stage or pasture vs. barn feeding on milk fat composition were negligible. Compared with the control, alpha-linolenic acid (18:3n-3) consumption was elevated in groups P and B (79%; P< 0.001) during the lowland periods but decreased on the alp to the level of C owing to feed intake depression and lower 18:3n-3 concentration in the alpine forage. Average 18:3n-3 contents of milk fat were higher in groups P and B than in C by 33% (P< 0.01) at low and by 96% (P < 0.001) at high altitude, indicating that 18:3n-3 levels in milk were to some extent independent of 18:3n-3 consumption. The cis-9, trans-11 CLA content in milk of grass-fed cows was higher compared with C but lower for the alpine vs. lowland periods whereas the trans-11, cis-13 isomer further increased with altitude. Long-chain n-3 FA and phytanic acid increased while arachidonic acid decreased with grass-only feeding, but none of them responded to altitude. Grass-only feeding increased milk alpha-tocopherol concentration by 86 and 134% at low and high altitude (P < 0.001), respectively. Changes in the ruminal ecosystem due to energy shortage or specific secondary plant metabolites are discussed as possible causes for the high 18:3n-3 concentrations in alpine milk.

Effect of Dietary Fat and Vitamin E on α-Tocopherol in Milk from Dairy Cows

Diets with different fat treatments and with 25, 125, or 250 IU of supplemental vitamin E (all-rac α-tocopheryl acetate)/kg of dry matter (DM) were fed for 28 d to midlactation Holstein cows to determine factors affecting concentrations of α-tocopherol in milk. Diets contained no supplemental fat or 2.25% added fat from roasted soybeans or tallow. Vitamin E treatment had no effects on production, but fat supplementation increased milk yield (37.2 vs. 35.1 kg/d). Cows fed RSB ate more DM (24.0 vs. 21.9 kg/d) and produced more milk fat than cows fed tallow. Supplemental fat increased plasma concentrations of α-tocopherol and cholesterol. Increased intake of α-tocopherol linearly increased concentrations of α-tocopherol in plasma but the rate of increase was 1.9 times greater when fat was fed. Plasma α-tocopherol concentrations were linearly related to concentrations in milk, but a change in plasma α-tocopherol resulted in a smaller change in milk α-tocopherol when fat was fed than when it was not. Fat treatment did not affect plasma α-tocopherol expressed relative to plasma cholesterol (mg α-tocopherol/g cholesterol) or relationships between plasma α-tocopherol/g of cholesterol and milk α-tocopherol. These data suggest that concentrations of α-tocopherol in milk are a function of the α-tocopherol enrichment of the plasma lipid fraction and enrichment of that fraction is saturable.

Milk Choline, α-Tocopherol and Neutrophil Chemotaxis in the Periparturient Dairy Cow

L. Pinotti*, R. Rebucci, E. Fusi, L. Rossi and A. Baldi Department of Veterinary Sciences and T echnology for Food Safety, Faculty of Veterinary Medicine, University of Milan, Milan, Italy *Correspondence: Dipartimento di Scienze e T ecnologie Veterinarie per la Sicurezza Alimentare, Facolta di Medicina Veterinaria, Universita degli Studi di Milano, V ia T rentacoste 2, 20134 Milano, Italy E-mail: luciano.pinotti@unimi.it