Effects of dietary vitamin C on neutrophil function and responses to intramammary infusion of lipopolysaccharide in periparturient dairy cows

Neutrophil function and the severity and incidence of mastitis in dairy cows is related to the intake of many antioxidant nutrients. Because vitamin C is the major water-soluble antioxidant in mammals, we examined the effect of dietary vitamin C on neutrophil function and responses to intramammary infusion of lipopolysaccahride (LPS) in periparturient dairy cows. At 2 wk before anticipated calving, Holstein cows were fed diets that provided 0 (16 cows) or 30 (15 cows) g/d of supplemental vitamin C (phosphorylated ascorbic acid). Treatments continued until 7 d after cows received an infusion of 10 μg of LPS into one quarter of the mammary gland (on average, this occurred 32 d postcalving). Supplementation of vitamin C increased plasma concentrations of vitamin C at calving, but no differences were observed in samples taken 24 h postinfusion. Concentrations of vitamin C in milk (24 h postinfusion) and in neutrophils (calving and 24 h postinfusion) were not affected by treatment, but vitamin C concentrations in neutrophils isolated from milk were about 3 times greater than concentrations in blood neutrophils. The LPS infusion did not alter concentrations of vitamin C in plasma or milk, suggesting that the LPS model did not produce the same effects as a bacterial infection of the mammary gland with respect to antioxidant effects. Supplemental vitamin C had no effect on neutrophil phagocytosis or bacterial kill. Dietary vitamin C reduced the milk somatic cell count but did not affect the febrile response or milk production following LPS infusion.     

维生素E在肉类加工中的应用

维生素是调节人体新陈代谢,维持机体生命和健康必不可缺少的元素。它不能在人体内合成,需从外界摄入,以满足人体的需要。本文将就维生素E对人体的功能及其在肉食加工中的应用作简单介绍。     

Long-term effects of feeding gossypol and vitamin E to dairy calves.

Male Holstein calves were used to test the effect of feeding 400 mg of free gossypol/kg of diet and to determine whether vitamin E could counteract gossypol toxicity. Fifty-two calves were allotted to treatments as follows: 1) soybean meal-based starter; 2) cottonseed meal-based starter; 3) cottonseed meal-based starter + 2000 IU of vitamin E/d per calf, and 4) cottonseed meal-based starter + 4000 IU of vitamin E/d per calf. Vitamin E supplementation (treatments 3 and 4) improved weight gain and feed intake over calves on treatment 1. Gossypol concentrations in plasma were higher in calves on treatments 2, 3, and 4 than in calves on treatment 1; however, no differences were observed among animals receiving the three cottonseed meal diets. Hemoglobin and hematocrit were decreased in calves receiving treatment 2, and vitamin E supplementation counteracted this effect (treatments 3 and 4). Plasma alpha-tocopherol concentrations were not affected by gossypol intake and followed the vitamin E supplementation pattern During the experimental period, 10 calves died, six from treatment 2 and two each from treatments 3 and 4. Necropsy findings from 4 of 10 calves were suggestive of gossypol toxicity. Histopathological examination revealed centrilobular necrosis in the liver and atrophy and vacuolation of cardiocytes. Feeding cottonseed meal caused death of some calves with gossypol related toxicity signs, but did not decrease plasma alpha-tocopherol; however, vitamin E supplementation increased performance and may have conferred some protection against gossypol toxicity.     

Response of lactating cows to 300 mg of supplemental vitamin E daily.

Ten Holstein cows in mid-lactation which had been fed only stored feeds for several years were paired on milk production. One cow from each pair was assigned to either the control or group treated with supplemental vitamin E for a 12-wk experiment. All cows were fed 3 kg alfalfa-brome hay, corn silage ad libitum, and concentrate at 1 kg/3 kg milk produced daily. This ration provided about 500 mg of vitamin E (total tocopherols) daily. Five cows were fed an additional 300 mg vitamin E daily as D-alpha-tocopherol acetate in their concentrate mix. Feeding the supplemental vitamin E increased the vitamin E content of milk fat 15 to 20% from 18 microgram/g fat to over 21 microgram/g fat. However, this change in vitamin E content of milk was not sufficient to improve the oxidative stability of the milk. Blood characteristics indicative of vitamin E status generally were unaffected by vitamin E supplementation although red cell hemolysis, glutamic oxaloacetic transaminase, and lactate dehydrogenase of serum were lower in blood of supplemented cows.     

Bovine vitamin A and beta-carotene intake and lactational status. 1. Responsiveness of peripheral blood polymorphonuclear leukocytes to vitamin A and beta-carotene challenge in vitro

Dietary vitamin A and beta-carotene were assessed on their interaction with lactational status to influence neutrophil function in vitro. Cows were fed 1) 53,000 IU or 2) 213,000 IU vitamin A, or 3) 53,000 IU vitamin A plus 400 mg beta-carotene/cow per d from 6 wk before to 2 wk after dry off. Blood neutrophils were isolated the day of dry off and 2 wk after dry off and incubated with retinol, retinoic acid, or beta-carotene. Phagocytosis and kill of Staphylococcus aureus were measured. Across all treatments, kill was higher after dry off than before dry off. Phagocytosis tended to be lower after dry off than before in cows fed vitamin A only. In vitro, 10(-6) M beta-carotene stimulated phagocytosis after dry off and kill before dry off in cows fed vitamin A only. In general, retinol and retinoic acid suppressed phagocytosis but did not affect kill. Neutrophils from cows fed high amounts of vitamin A were more susceptible to in vitro suppression than those from cows fed adequate amounts of vitamin A. Therefore, vitamin A and beta-carotene supplementation interacts with lactational status to influence the responsiveness of bovine neutrophils to vitamin challenge in vitro.     

Bovine vitamin A and beta-carotene intake and lactational status. 2. Responsiveness of mitogen-stimulated peripheral blood lymphocytes to vitamin A and beta-carotene challenge in vitro

The interaction of dietary vitamin A and beta-carotene with lactational status on the in vitro proliferation of mitogen-induced peripheral blood lymphocytes was studied. Cows were fed (IU/cow per d) 1) 53,000 IU vitamin A, 2) 213,000 IU vitamin A, or 3) 53,000 IU vitamin A plus 400 mg beta-carotene from 6 wk before to 2 wk after dry off. Lymphocytes were incubated with retinol, retinoic acid, or beta-carotene. Concanavalin A-induced blastogenesis was inhibited by 10(-6) M retinol and 10(-8) M retinoic acid in cows fed 53,000 IU vitamin A before dry off. In contrast, 10(-7) M retinol and 10(-7) M retinoic acid stimulated Concanavalin A-induced blastogenesis for cows fed vitamin A plus beta-carotene before dry off. After dry off, retinol and retinoic acid did not affect Concanavalin A-induced blastogenesis in all treatment groups. In vitro, 10(-5) M beta-carotene inhibited Concanavalin A-induced blastogenesis before and after dry off in all treatment groups. Blastogenesis in the absence of mitogen stimulation or induced by lipopolysaccharide was inhibited by all vitamins before and after dry off in all treatment groups. These data indicate that vitamin A and beta-carotene supplementation interact with lactational status to influence the responsiveness of bovine blood lymphocytes to vitamin challenge in vitro.     

微胶囊化天然维生素E的研究

对制造胶囊化天然维生素E粉末的工艺和技术进行了研究。工艺过程包括乳化液的制备和喷雾干燥造粒。影响工艺及产品 因素包括原料配方，乳化工艺条件，均质压力及喷雾干燥造粒工艺条件等。性状分析及贮实验表明：微胶囊型天然维生素E的水溶性，流动性，分散性及稳定性等性能指标均好。     

维生素E油酸酯的合成研究

以维生素E及油酸为原料,乙酸酐为共反应剂,三乙胺为催化剂合成了维生素E油酸酯。讨论了原料配比、催化剂用量、反应温度和反应时间等4个因素对维生素E油酸酯产率的影响,并采用TLC和HPLC法对产品进行分析。结果表明,最佳合成工艺为维生素E与中间体的摩尔配比为1∶2.0,催化剂用量0.15 mL,反应时间5 h,反应温度为40℃,在此条件下反应产率为31.94%。     

Effect of vitamin E supplementation on neutrophil function, milk composition and plasmin activity in dairy cows in a commercial herd

Fifty-six Holstein dairy cows from a commercial dairy herd in the Northern part of Greece were used to determine the effect of vitamin E supplementation on immune parameters, milk composition and milk quality. Cows were assigned to one of two experimental groups: control (no vitamin E supplementation) and vitamin E supplementation. Supplementation of vitamin E started 4 weeks prior to and continued up to 12 weeks after parturition. Supplementation included daily oral administration of vitamin E at 3000 i.u./cow prepartum and was reduced to 1000 i.u./cow post partum. Blood samples were collected weekly for 8 weeks starting 4 weeks before parturition, neutrophils were isolated and the following parameters were determined in neutrophils activated by phorbol myristate acetate: total cell-associated and membrane-bound urokinase plasminogen activator (u-PA) activity and superoxide production. Milk samples were collected weekly and fat, protein, lactose, somatic cell count (SCC), plasmin and plasminogen-derived activity were determined. Activated neutrophils isolated from cows that received supplemental vitamin E had higher (P<0.01) total and membrane-bound u-PA activities during the first 3 weeks after parturition and higher (P<0.01) superoxide production during week 1 prepartum and week 1 post partum compared with the corresponding values of activated neutrophils isolated from control cows. Vitamin E supplementation had no effect (P=0.28) on plasminogen-derived activity in milk. Milk obtained from cows that received supplemental vitamin E had SCC lower by 25% (P<0.05) and plasmin lower by 30% (P<0.01) than corresponding values in milk obtained from control cows. The reduction in plasmin as a result of vitamin E supplementation is very beneficial to the dairy industry because plasmin reduces the cheese-yielding capacity of milk, affects the coagulating properties of milk and its overall ability to withstand processing during cheesemaking. In conclusion, vitamin E supplementation had positive effects on the function of bovine neutrophils and milk quality in a commercial dairy herd.     

维生素E微胶囊化研究

以变性淀粉为壁材、PEG400-单油酸为乳化剂，对维生素E微胶囊化的配方和工艺进行了研究。试验结果表明最佳条件为：维生素E、变性淀粉、PEG400-单油酸、海藻酸钠的比例为25：30：5：0．6，固形物含量30％，均质压力30MPa，均质温度60℃，喷雾进风温度185—195℃，进料温度60℃。     

天然维生素E琥珀酸酯的制备

维生素E琥珀酸酯有比维生素E更强的化学稳定性,同时其还有抗癌功效,是水溶性维生素E--TPGS的基本原料.介绍了用天然维生素E酯化制备维生素E琥珀酸酯的方法,选用三乙胺作为催化剂制备维生素E琥珀酸酯.通过实验优化后得到优化的工艺条件为(原料50 g):反应时间为4.0 h、琥珀酸酐用量为原料维生素E的150%(W/W)、催化剂用量为5.0 mL、反应温度为55℃.在优化的工艺条件下,维生素E酯化率为93.91%.     

维生素E干粉质量评价研究

目的:对喷雾干燥法生产的维生素E干粉进行质量研究,为维生素E干粉产品质量控制和应用提供科学依据。方法:对10个批次喷雾干燥法生产的维生素E干粉进行物理性质、化学性质和产品应用性评价,以外观、产品长期和加速稳定性、粒度分布、水分活度、休止角、松紧密度、冷水溶解性及漂油情况、水溶液及高糖高酸体系稳定性为指标,对喷雾干燥法生产的维生素E干粉的质量进行详细的考察。结果:喷雾干燥法生产的维生素E干粉为白色至类白色流动性粉末,无明显异物存在,加速稳定性试验条件下储存6个月和长期稳定性试验条件下储存36个月外观无明显改变;维生素E干粉的休止角为35.23±2.40°,水分活度为0.339±0.043,松密度为0.431±0.018g/cm3,紧密度为0.502±0.022g/cm3,粒度主要分布在60~100目之间;在加速稳定性试验条件下储存6个月的含量保留率为99.97±0.12%,长期稳定性试验条件下储存36个月的含量保留率为99.98±0.32%;维生素E干粉在冷水呈小蝌蚪状拖尾下落,并且在冷水中均匀分散,搅拌均匀后无结团、无漂油;维生素E干粉在水溶液和高糖高酸体系中稳定性良好。结论:维生素E干粉冷水分散,稳定性好、应用性能优异。     

维生素E的最新研究进展及应用前景

综述了维生素E的制备方法、检测方法以及膳食摄入量,对维生素E的开发现状和未来前景进行了探讨。     

水分散性维生素E的研究

采用乳化的方法将维生素E转化为水溶性乳状液,以提高维生素E的利用率。采用转相乳化法制备维生素E乳状液,最佳的乳化剂吐温-80与司盘-80的配比为2∶3,乳化剂添加量为37.5%,乳化时间为10 min。     

维生素E对猪肉品质的影响

主要介绍维生素E独特的抗氧化作用,以及维生素E是如何支持肉类的稳定性。此外,还介绍了维生素E的作用方式,添加要求和功效。     

保健食用油一紫苏油研究进展

紫苏油作为一种优良的保健食用油,对其组成成分、理化性质和生理作用等作了综述,并对其开发前景进行了展望.     

HPLC法同时测定保健食品中维生素A和维生素E

建立了高效液相色谱法(HPLC)同时测定保健食品中VA、VE的方法。样品预处理采用经二甲亚砜和正己烷的混合溶液于60℃剧烈振摇提取30min,离心后吸取正己烷层,合并3次提取的溶液后直接进行液相色谱测定。方法采用Inertsil氨基柱(4.6 mm×250 mm,5μm),以含0.1%异丙醇的正己烷为流动相进行等度洗脱,流速为1.0 m L/min,检测波长为280nm,柱温为25℃。结果表明,VA、VE分别在5~25μg/m L、100~500μg/m L范围内线性关系良好,相关系数分别达0.9997和0.9998,保留时间和峰面积的日内和日间精密度均较好,平均加标回收率在97.53%~100.67%之间,相对标准偏差(RSD)均小于2.0%。与相应的检验标准测定结果比较,相对偏差均小于1.0%,无明显差异。该方法快速、准确、可靠,适用于不同厂家、不同配方的保健食品中添加合成VA、VE的同时定量测定。     

Electrochemical determination of vitamin E in margarine, butter and palm oil.

A simple, rapid and reproducible method is described for the analysis of tocopherols in margarine, butter and palm oil. The method involves saponification, extraction of the unsaponifiable material and direct voltammetric determination. No separation technique is necessary. Two indicator electrodes, glassy carbon (GCE) and carbon paste (CPE), have been employed in this work, GCE in ethanol-benzene (2:1) medium and CPE in 75% ethanol. The CPE gives over ten times as much current as the GCE for a given tocopherol concentration. The GCE' high residual current in aqueous medium makes it impractical in 75% aqueous ethanol and the CPE' solubility in benzene restricts its usage in ethanol-benzene medium. Slight turbidity does occur sometimes when the unsaponifiable material of the samples is dissolved in 75% ethanol but this seems not to interfere in subsequent analysis. Increase in ethanol content to 90% gives a clearer solution and higher background, but no appreciable difference in the results. The results obtained by use of both electrodes are given and shown to be in close agreement with previously published results.     

天然维生素E提取工艺研究进展

天然维生素E是一种具有良好生理功能和药理价值的抗氧化剂,具有广阔的开发前景和市场需求。综述了天然维生素E的性质、应用及提取方法,重点介绍了国内外提取天然维生素E的生产工艺,进展情况,对今后开展天然维生素E的进一步深入研究具有一定参考价值。     

合成维生素E的研究进展

维生素E是一种具有良好生理活性和药理价值的抗氧化剂,市场需求量不断增长,目前人们获得维生素E的80％来自于合成产品.对合成工艺进行改进,制备高纯度的合成维生素E产品,具有广阔的发展前景.本文简要阐述了合成维生素E的两种原料三甲基氢醌及异植物醇的制备方法,着重介绍了合成维生素E的催化体系与溶剂体系,并对存在的问题及研究发展前景进行了评述.