青藏高原高寒植物及牦牛奶抗氧化特性研究

发布时间：2018-01-17 18:21

本文关键词：青藏高原高寒植物及牦牛奶抗氧化特性研究　出处：《兰州大学》2016年博士论文　论文类型：学位论文

【摘要】：青藏高原是世界上海拔最高、面积最大的高原,总面积达250万平方公里,约占我国草地总面积的三分之一。严寒、缺氧、强烈的紫外辐射是其最主要的特征。青藏高原上恶劣的环境胁迫会使有机体处于氧化应激状态,另外营养缺乏和体力活动也会加重有机体面临的氧化压力。人类和动物可以通过减少体力活动或者(和)增加抗氧化物质的摄入来减轻体内的氧化压力。营养素的摄入一方面可以减少自由基的生成,另一方面也可以修复自由基损伤。由于特殊的地理位置和文化习俗,青藏高原原著牧民食物结构较为单一,糌粑、牛羊肉、牦牛奶、酸奶、酥油等是他们最主要的食物。本文从植物-动物-人这一食物链的角度出发,研究测定了青藏高原的牧草和牦牛奶的总抗氧化能力和抗氧化成分,探究青藏高原生态系统中牧草、牦牛和牧民适应高寒胁迫环境的营养学机制。此外,本研究还对藏区牧民进行了膳食调查,探讨传统饮食习惯的改变对牧民健康的潜在影响。主要研究结果如下:(1)不同海拔高度5种高寒植物总抗氧化能力和抗氧化成分研究。选取青藏高原海拔3016米、3814米、4621米处的五种高寒植物,包括一种莎草,藏嵩草(Kobresia tibetica);两种杂草,珠芽蓼(Polygonum viviparum)和黄花棘豆(Oxytropis ochrocephala);还有两种灌木,金露梅(Potentilla fruticosa)和山生柳(Salix oritrepha)。5种植物的粗蛋白、脂肪的含量随海拔的升高而增加(P0.05),矿物质元素的含量则随海拔的升高而降低(P0.05)。5种植物的总抗氧化能力均随海拔的升高而增加(P0.05),总酚和单宁的含量随海拔的升高而增加(P0.05),单不饱和脂肪酸、多不饱和脂肪酸、亚麻酸、亚油酸均随海拔的升高而增加(P0.05),它们为青藏高原牦牛生产高营养物质的牛奶尤其是富含多不饱和脂肪酸的牛奶提供了物质基础。(2)青藏高原18种高寒植物抗氧化能力和抗氧化成分研究。试验选取了青藏高原乌鞘岭地区的18种牧草,包括4种莎草:藏嵩草(Kobresia tibetica)、矮生嵩草(Kobresia humilis)、线叶嵩草(Kobresia capillifolia)和喜马拉雅嵩草(Kobresia royleana);5种禾草:垂穗披碱草(Elymus nutans)、短芒洽草(Koeleria litwinowii)、草地早熟禾(Poa pratensis)、藏异燕麦(Helictotrichon tibeticum)和短花针茅(stipabreviflora);5种杂草:珠芽蓼(polygonumviviparum)、秦艽(gentianamacrophylla)、马蔺(irislacteapall.var.chinensis)、问荆(equisetumarvense)和黄花棘豆(oxytropisochrocephala);4种灌木:金露梅(potentillafruticosa)、山生柳(salixoritrepha)、鬼箭锦鸡儿(caraganajubata)和短叶锦鸡儿(caraganajubata)。18种高寒植物的粗蛋白含量在9.1—25.2g/100gdm范围内,18种高寒植物的平均灰分含量为6.94g/100gdm,除了na远低于牲畜的需要量外,其它矿物质元素如ca,p,k,mg,cu,fe,mn,zn均能满足牲畜的需要。α-亚麻酸(cis-9,cis-12,cis-15c18:3),亚油酸(cis-9,cis-12c18:2)、棕榈酸(c16:0)约占高寒植物脂肪酸总量的83%左右。与杂类草和灌木相比,莎草和禾草含有更丰富的多不饱和脂肪酸。高海拔地区植物中高含量的多不饱和脂肪酸为反刍动物合成共轭亚油酸和n-3多不饱和脂肪酸提供了基础。除藏嵩草(kobresiatibetica)外其它三种莎草科植物都具有中等水平抗氧化能力,除短叶锦鸡儿(caraganajubata)外其它三种灌木都具有高等水平抗氧化能力。研究发现植物的营养价值和抗氧化能力随着海拔的升高而增加,夏季,莎草占牦牛干物质采食量的64%左右,我们推测青藏高原地区夏季莎草的抗氧化能力对于维持牦牛抗氧化健康来说是足够的。(3)青藏高原不同海拔高度牦牛奶的总抗氧化能力和抗氧化成分研究。选取甘肃省天祝藏族自治县乌鞘岭地区(37°12'02"nand102°51'38"e,altitude3016m),青海省果洛藏族自治州玛沁县大武镇(34°27'37"(34°27'37"nand100°12'35"e,altitude3824m)和西藏自治区那曲地区的古露镇(30°58'87"nand91°37'39"e,altitude4750m)为三个采样点。在每个采样点随机选取传统饲养方式下的泌乳牦牛各20头(年龄7-11岁,体重250-280kg,胎次为3-4次,产奶量相近,处于同一泌乳期的健康家养牦牛)。7月中旬、下旬和8月上旬,分别在天祝乌鞘岭、果洛大武镇和那曲古露进行采样。研究发现,牦牛奶和牧草的粗蛋白含量随海拔的升高而降低,牧草中性洗涤纤维和牦牛奶脂肪含量随海拔的升高而增加。牦牛奶的总抗氧化能力,维生素a,脂肪,共轭亚油酸,γ-亚麻酸,不饱和脂肪酸,fe、zn、na含量均随海拔的升高而增加(p0.05),维生素c、粗蛋白、cu和mn的含量随海拔的升高而降低(p0.05)。另外,两个较高海拔地区大武镇和古露镇牦牛奶的动脉粥样硬化指数(ai)显著低于乌鞘岭地区(p0.05)。研究证明牦牛奶的营养价值随海拔的升高而增加,而且显著高于商品牛奶。(4)随着社会经济的繁荣发展,牧民的饮食习惯也发生了巨大的改变,牧民的牦牛奶及奶制品消费量有所下降,与1986年的定居牧民相比,牦牛奶的消费量下降了近2/3;出于经济的考虑,牧民出售牦牛奶,购入商品奶或奶制品以供日常消费,这都会造成牧民功能性营养成分摄入量降低,将对牧民的身体健康产生影响。同时我们也发现,牧民的蔬菜消费量有所增加。牧民膳食结构的改变会如何影响他们的健康,这一问题应该引起更多研究者的关注。
[Abstract]:The Tibetan Plateau is the world's highest, the largest area of the plateau, a total area of 2 million 500 thousand square kilometers, accounting for about 1/3 of the total area of grassland in China. The cold, hypoxia, strong ultraviolet radiation is the most important feature of Tibetan Plateau. The bad environment stress caused oxidative stress in the organism, in addition to the lack of nutrition and physical activity may increase oxidative stress organisms face. Human and animal can reduce physical activity or (and) increased intake of antioxidants to reduce oxidative stress in vivo. Nutrient intake on the one hand to reduce the generation of free radicals, on the other hand can also repair free radical damage. Because of the special geography the position and structure of the original food culture and customs, herdsmen in Qinghai Tibet Plateau is relatively single, roasted barley flour, beef and mutton, yak milk, yogurt, butter is their main food. From the plant animal The food chain perspective, the total antioxidant capacity and antioxidant components of Tibetan Plateau forage and yak milk samples was on pasture ecosystem in Tibetan Plateau, yak and herdsman to nutrition stress mechanism in alpine environment. In addition, this study also conducted a dietary survey of Tibetan herdsmen, explore the traditional eating habits the change of the potential impact on the health of herdsmen. The main results are as follows: (1) of the total antioxidant capacity and antioxidant components at different altitudes of 5 alpine plants. Selected Tibetan plateau at an altitude of 3016 meters, 3814 meters, five meters of 4621 alpine plants, including sedge, Tibet Kobresia (Kobresia tibetica); two weed species, Polygonum viviparum (Polygonum viviparum) and O.ochrocephala (Oxytropis ochrocephala); there are two kinds of shrubs, Jin Lumei (Potentilla fruticosa) and Salix oritrepha (Salix oritrepha).5 crude protein species White, fat content increased with the increase of elevation (P0.05), and decrease the content of mineral elements, with the increase of altitude (P0.05) total antioxidant capacity of.5 plants were increased with the increase of altitude (P0.05), total phenolics and tannin content increased with the increase of elevation (P0.05). Monounsaturated fatty acids, polyunsaturated fatty acid, linolenic acid, linoleic acid were increased with the increase of altitude (P0.05), they are for the production of high nutrient of the plateau yak milk is especially rich in polyunsaturated fatty acid milk provides the material basis. (2) study on the antioxidant ability of 18 kinds of alpine plants the Qinghai Tibet Plateau and antioxidants. The test selected 18 kinds of forage wushao ridge area of Tibet Plateau, including 4 species of sedges: Tibet Kobresia (Kobresia tibetica), K.humilis (Kobresia humilis), Kobresia capillifolia (Kobresia capillifolia) and Kobresia royleana (in Himalaya ); 5 species: Elymus nutans (Elymus nutans), short awn grass (Koeleria, litwinowii) - Kentucky Bluegrass (Poa pratensis), Tibet (Helictotrichon tibeticum) and different oat stipabreviflora (stipabreviflora); 5 kinds of weeds: Polygonum viviparum (polygonumviviparum), Gentiana (gentianamacrophylla), irisquinone (irislacteapall.var.chinensis), horsetail (equisetumarvense) and O.ochrocephala (oxytropisochrocephala); 4 species of shrubs: Jin Lumei (potentillafruticosa), Salix oritrepha (salixoritrepha), Caragana jubata (caraganajubata) and short c.acanthophylla (caraganajubata).18 crude protein content of alpine plants in 9.1, in the range of 25.2g/100gdm, the average ash content 18 kinds of alpine plants for 6.94g/100gdm, in addition to Na is far lower than the demand for livestock and other mineral elements such as Ca, P, K, Mg, Cu, Fe, Mn, Zn are able to meet the needs of livestock. Alpha linolenic acid (cis-9, cis-12, cis-15c1 8:3), linoleic acid (cis-9, cis-12c18:2), palmitic acid (c16:0) of total fatty acids of 83% alpine plants. Compared with forbs and shrubs, sedges and grasses rich in polyunsaturated fatty acids. The high content of plants in high altitude area of polyunsaturated fatty acids for the synthesis of conjugate ruminant animal linoleic acid and n-3 polyunsaturated fatty acids to provide a basis. In addition to Tibet Kobresia (kobresiatibetica) and the other three species of Cyperaceae family have antioxidant capacity in the middle level, short leaves of Caragana (caraganajubata) and other three kinds of shrubs have high antioxidant capacity levels. The study found that the nutritional value and antioxidant capacity of plants increased with the increase of altitude in summer, sedge accounted for yak dry matter intake by about 64%, we speculate that summer sedge in Tibetan Plateau to maintain the antioxidant capacity of yak antioxidant health is enough . (3) of the total antioxidant capacity and antioxidant components of the plateau yak milk. At different altitudes in Gansu province were selected in Tianzhu Tibetan Autonomous County of Wushaoling area (37 "12'02" nand102 "51'38" E, altitude3016m), Dawu town in Qinghai province Golog Tibetan Autonomous Prefecture Maqin county (34 degrees 27'37 (34 degrees "27'37" nand100 "E, altitude3824m ~ 12'35) and Naqu Prefecture of Tibet ancient Lu Zhen (30 degrees 58'87 degrees 37'39" nand91 "E, altitude4750m) for the three sampling points at each sampling point. Lactating yaks were randomly selected traditional feeding mode under each of the 20 head (age 7-11 years old, weight 250-280kg, parity 3-4, with similar milk yield, in the same lactation healthy domestic yak).7 month, late and early August, respectively in Tianzhu Wushaoling, Golog Dawu town and Naqu gulog were sampled. The study found that the crude protein content of yak milk and grass decreased with the increase of altitude, and animal husbandry Grass NDF and yak milk fat content increased with the increase of elevation. The total antioxidant capacity of yak milk, vitamin A, fat, conjugated linoleic acid, linolenic acid, unsaturated fatty acid, Fe, Zn, Na contents were increased with the increase of altitude (P0.05), vitamin C, crude protein the content of Cu, and Mn decreased with the increase of altitude (P0.05). In addition, and Gu Lu Zhen yak milk two high altitude areas in Dawu town of atherosclerosis index (AI) was significantly lower than that of Wushaoling area (P0.05). The study shows that the nutritional value of yak milk increased with the increase of elevation, and was significantly higher than that of commodity milk. (4) with the economic prosperity and social development, and eating habits have changed dramatically, yak milk and dairy products consumption herders declined, compared with 1986 settled herdsmen, consumption of yak milk is down nearly 2/3; out of economic considerations, animal husbandry People buy goods sell yak milk, milk or milk products for daily consumption, which will cause the decrease of functional nutrients intake of pastoralists, herders will have an impact on health. At the same time we also found that vegetable consumption increased. The herdsmen change herdsmen dietary structure how to affect their health, this a problem should be paid more attention by researchers.

【学位授予单位】：兰州大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：S812;S879.1;R151

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