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微胶囊的理化性质表征

采用超声波辅助β-环糊精(β-CD)对维生素E进行包埋,而后再加入乳清浓缩蛋白(WPC)对其进行二次包埋来制备维生素E微胶囊.通过扫描电镜(SEM)发现微胶囊产品与物理混合物的微观形态存在较大差异;在微胶囊产品的差示热扫描(DSC)图谱中出现了一个新的吸热峰;傅里叶变换红外光谱(FT-IR)显示,在微胶囊产品中没有发现维生素E的特征峰并且存在较强的氢键效应;微胶囊产品的X-射线衍射图谱与物理混合物以及β-环糊精的图谱大不相同,在多处变化明显;以上的实验结果证实了维生素E已经被β-环糊精和乳清浓缩蛋白包埋,并且维生素E与β-环糊精之间发生氢键作用形成包合物.     

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。     

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℃。     

Chemistry and biology of vitamin E

Our understanding of the role of vitamin E in human nutrition, health, and disease has broadened and changed over the past two decades. Viewed initially as nature's most potent lipid-soluble antioxidant (and discovered for its crucial role in mammalian reproduction) we have now come to realize that vitamin E action has many more facets, depending on the physiological context. Although mainly acting as an antioxidant, vitamin E can also be a pro-oxidant; it can even have nonantioxidant functions: as a signaling molecule, as a regulator of gene expression, and, possibly, in the prevention of cancer and atherosclerosis. Since the term vitamin E encompasses a group of eight structurally related tocopherols and tocotrienols, individual isomers have different propensities with respect to these novel, nontraditional roles. The particular beneficial effects of the individual isomers have to be considered when dissecting the physiological impact of dietary vitamin E or supplements (mainly containing only the alpha-tocopherol isomer) in clinical trials. These considerations are also relevant for the design of transgenic crop plants with the goal of enhancing vitamin E content because an engineered biosynthetic pathway may be biased toward formation of one isomer. In contrast to the tremendous recent advances in knowledge of vitamin E chemistry and biology, there is little hard evidence from clinical and epidemiologic studies on the beneficial effects of supplementation with vitamin E beyond the essential requirement.     

角鲨烯和维生素E抗皮肤衰老作用的比较研究

研究角鲨烯对皮肤的抗衰老作用并与维生素E进行比较。在10%新鲜猪皮匀浆中分别添加体积为20、40、60、80、100μL的角鲨烯和维生素E,测定猪皮组织匀浆中超氧化物歧化酶（SOD）、谷胱甘肽过氧化物酶（GSH-Px）、过氧化氢酶（CAT）活力,并通过吸光值间接反映了蛋白质羰基和蛋白质氢过氧化物含量变化,以空白作为对照。结果表明角鲨烯能显著提高猪皮SOD、GSH-Px和CAT的活力,同时能显著降低皮肤中蛋白质羰基和蛋白质氢过氧化物含量,且效果较维生素E明显。表明角鲨烯对皮肤有一定的抗衰老作用。      

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。     

维生素E辛烯基琥珀酸酯的合成工艺优化

以4-二甲氨基吡啶（DMAP）和锌粉（Zn）为催化剂,维生素E（V E）和辛烯基琥珀酸酐（OSA）经合成得到维生素E辛烯基琥珀酸酯（V E-OS酯）。通过考察各反应因素对合成工艺的影响,在进行单因素实验的基础上,利用响应面法优化V E-OS酯的合成工艺,建立了拟合良好的数学模型。结果表明,DMAP用量对合成工艺影响最显著;拟合得到的最优合成工艺为OSA与V E的摩尔比为2.3∶1,DMAP与V E的摩尔比为0.2∶1,乙酸乙酯用量61.67mL。拟合得V E理论转化率为100%,验证实验得到V E实际转化率为99.04%,说明响应面法优化有效。