饲喂膨化全脂大豆对奶牛组织中PUFAs及CLA含量变化的影响

本文旨在研究高产奶牛饲喂膨化全脂大豆对奶牛组织PUFAs及CLA含量变化的影响。选取12头年龄、体重、胎次、泌乳期及泌乳量相近的荷斯坦奶牛随机分为试验组和对照组,每组6头进行饲养试验。在饲喂全混合日粮的基础上,试验组每天饲喂1 kg膨化全脂大豆,对照组不添加,试验期12周。试验结束后屠宰奶牛并取肝脏、肾脏、乳腺3种组织中带有导管的部位,分别测定各组织PUFAs及CLA含量。结果表明:(1)添加膨化全脂大豆对奶牛肝脏、肾脏和乳腺等组织脂肪酸的合成转化产生不同的影响,日粮脂肪酸在组织内转化过程中可能受多种酶的作用;(2)乳腺C18∶1 trans-11在对照组为0.57%,而试验组为27.01%,差异极显著(P<0.01),乳腺是合成转化PUFAs及CLA主要组织,同时也是牛乳中PUFAs及CLA主要来源。奶牛日粮添加膨化全脂大豆能够显著改善牛乳品质;与肝脏、肾脏相比,乳腺具有更高的长链不饱和脂肪酸含量;肝脏、肾脏、乳腺在对日粮脂肪酸合成与转化过程中相关性不显著。     

奶牛胎次对乳中 CLA 含量和△9-去饱和酶指数的影响

选择235头健康的中国北方荷斯坦奶牛为研究对象,为避免日粮和季节的影响,奶牛饲喂同种日粮,采集同一天的乳样,测定奶牛泌乳性能和乳脂肪酸组成,研究胎次对乳中CLA含量和△^9-去饱和酶指数的影响。研究结果表明：乳中c9,t11 CLA含量平均为5．14mg／g脂肪酸,变化范围1．5～10．5mg／g脂肪酸。初产奶牛的c9,t11 CLA平均含量为5．19mg／g脂肪酸,而经产奶牛的c9,t11 CLA平均含量为5．11mg／g脂肪酸,但二者间差异不显著（P〉0．05）,初产与经产奶牛之间的c9 C14：1去饱和酶指数和c9 C16：1去饱和酶指数差异显著（P〈0．05）。初产奶牛的c9 C18：1去饱和酶指数和c9,t11 CLA去饱和酶指数与经产奶牛的差异不显著（P〉0．05）。     

共轭亚油酸诱导的奶牛低脂乳症中脂肪球膜甘油磷脂的组成差异分析

旨在分析共轭亚油酸(CLA)诱导奶牛低脂乳症对牛乳脂肪球膜甘油磷脂含量的影响.选取体况相近、泌乳中期的10头荷斯坦奶牛进行自身前后对照设计,试验期12 d,第1天至第6天每头牛饲喂基础日粮+CLA 400 g·d-1,第7天至第12天恢复为饲喂基础日粮,每天记录产奶量及采食量,分析乳成分及乳脂肪球(MFG)粒径参数,对...     

日粮添加Trans-18:1亚油酸钙盐或共轭亚油酸钙盐后泌乳期奶牛乳脂的变化

在泌乳期奶牛日粮中添加trans-18：1亚油酸钙盐(Ca-tFA)或共轭亚油酸钙盐(Ca-CLA)测定乳脂变化。45头荷斯坦奶牛(115d，产奶期)，饲喂添加400g EnerG Ⅱ(棕榈油脂肪酸钙盐)对照日粮(51％饲草，以干物质为基础)2周；之后，采用随机区组设计分为5组，每组9头，分别饲喂对照日粮、添加100g Ca-CLA的日粮和分别添加100、200、400g Ca-tFA的日粮，饲喂4周。各处理组奶牛的干物质进食量、产奶量、乳蛋白、乳糖和体细胞数没有受到影响。乳脂率从3．39％(对照组)降到3．3％(100g Ca-tFA)、3．04％(200g Ca-tFA)、2．98％(400g Ca-tFA)和2．54％(Ca-CLA)。乳脂量(对照组1．24kg／d)随Ca-tFA添加量的增加分别下降了60、130、190g／d，Ca-CLA组下降了290g／d。添加Ca-tFA增加了内源cis-9-共轭亚油酸的合成。所以日粮中添加Ca-CLA或Ca-tFA乳中总CLA含量相似。与对照组相比，添加Ca-CLA增加了乳中trans-10 CLA、cis-12-18：2CLA的含量，但trans-18：1CLA异构体的水平没有改变；添加Ca-tFA组乳中多数的trans-18：1CLA异构体含量增加，但trans-10、cis-12-18：2CLA的含量与对照组相似。结论：乳脂降低与乳中trans-10CLA、cis-12-18：2CLA和其它成分的含量无关，可能与trans-10-18：1CLA异构体有关。     

国外畜牧科技

本试验旨在研究日粮中添加植物油对高产奶牛生产性能和乳脂中共轭亚油酸(CLA)含量的影响.采用12头泌乳早期(产后30～45 d)荷斯坦奶牛进行三重4×4拉丁方设计.每期试验基础日粮相同,设4个处理组:①对照组(不加油);②添加500 g棉籽油;③添加500 g大豆油;④添加500 g玉米油;每期试验3周,其中前2周为过渡期.试验结果表明日粮中添加植物油有提高产奶量的趋势(棉籽油组产奶量达35.0 kg/d,对照组产奶量34.4 kg/d).乳脂率降低,但乳蛋白率、乳蛋白产量和乳脂产量没有影响.大豆油组乳脂中trans-11 C18∶1含量最高 (23.8 mg/g乳脂),是对照组(12.6 mg/g乳脂)的2倍.与对照组(3.5 mg/g)相比,棉籽油组、玉米油组和大豆油组乳脂中cis-9,trans-11 CLA含量分别提高到6.0、7.1和10.3 mg/g.trans-11 C18∶1与cis-9,trans-11 CLA呈显著的线型关系.添加植物油使奶牛血浆总脂肪酸含量提高2倍,不同来源植物油的试验组差异不显著.大豆油组和棉籽油组奶牛血浆中硬脂酸含量显著高于玉米油组和对照组.添加植物油组奶牛血浆中trans-11 C18∶1显著高于对照组.日粮中添加CLA有提高产奶量的趋势,可显著提高乳脂中CLA含量,大豆油是提高乳脂中CLA含量较为理想的植物油来源.     

富含共轭亚油酸牛奶的生产原理和方法

本文综述了共轭亚油酸(CLA)的理化特性,乳脂CLA的合成途径,影响乳脂CLA含量的日粮因素及其通过营养调控提高奶牛乳脂CLA的方法。     

共轭亚油酸及其在驴乳中含量

共轭亚油酸(CLA)是由亚油酸衍生的一组亚油酸异构体,具有一系列生理活性功能。本文介绍了CLA的健康效应,乳中CLA的来源以及驴乳和驴乳脂中CLA的含量,认为低乳脂率驴乳乳脂CLA浓度高,可作为功能性保健食品的原料。文章对驴乳乳脂率和CLA浓度的关系进行了初步分析,指出乳脂率和全乳CLA浓度呈正相关,和乳脂CLA浓度呈负相关。建议通过改善驴的饲养管理、优化日粮结构、饲喂优质牧草等措施,提高驴乳的乳脂率和全乳CLA浓度,保证驴乳的质量。     

调控牛乳中共轭亚油酸含量的研究进展

介绍了共轭亚油酸(CLA)的来源和在人体中的生理作用,重点阐述影响牛乳中CLA含量的因素,包括在日粮中添加油脂、饲喂制度、季节变化和地理位置,提出了调控牛乳中CLA的含量的两种途径:改变日粮和饲养管理方式。     

调控牛乳中共轭亚油酸含量的研究进展

介绍了共轭亚油酸(CLA)的来源和在人体中的生理作用,重点阐述影响牛乳中CLA含量的因素,包括在日粮中添加油脂、饲喂制度、季节变化和地理位置,提出了调控牛乳中CLA的含量的两种途径改变日粮和饲养管理方式.     

饲喂含少量鱼油的挤压大豆对奶牛产奶量及牛乳成分的影响

美国南达科他州立大学的Schingoethe教授等为22.6kg/d,中鱼油日粮组为22.8kg/d,高鱼油日利用8头经产荷斯坦奶牛(泌乳期189±57d)和4头粮组为22.9kg/d。日粮中含有脂肪添加剂,可使产经产瑞士褐牛(泌乳期126±29d)进行试验。采用一奶量高于对照组,但乳脂和乳中真蛋白含量却下降。个重复的4×4拉丁方设计,试验期28d。测定在日粮日粮中含有脂肪添加剂使乳中cis-9、trans-11CLA中添加最小浓度的鱼油以获得牛乳中最高浓度的含量均得到提高,饲喂低鱼油日粮和高鱼油日粮的共轭亚油酸(CLA)和花生油酸(VA)的需要量。试验牛奶中VA含量显著升高,所…     

Biological effects of conjugated linoleic acids supplementation

Conjugated linoleic acids (CLA) are a group of polyunsaturated fatty acids (PUFA) with a single pair of conjugated double bonds. The major natural CLA isomer is 18:2 cis-9, trans-11 (c9, t11) linoleic acid, or rumenic acid (RA). Chemically synthesized CLA is also available, mostly as a mixture of RA and 18:2 trans-10, cis-12 (t10, c12) isomers in equal amounts (50:50). Consumption of ruminant meat (beef and lamb) and dairy products (milk and cheese) is the main source of dietary exposure to CLA. Despite numerous studies on animal and human models (tumorigenesis, obesity, immune response) it has not been established whether additional supplementation of CLA is of benefit. Moreover, some studies, conducted both in animals and in humans, reveal that CLA isomers may induce insulin resistance. Presently, balanced diet rich in CLA from natural sources is recommended. The purpose of this review was to sum up the results available in the literature.     

瘤胃保护共轭亚油酸和亚油酸对奶牛产奶性能的影响

选择健康、泌乳月份与产奶量相近的多胎荷斯坦泌乳牛20头,随机分成5组,每组4头,研究日粮中添加商业来源的瘤胃保护共轭亚油酸钙盐(Ca-CLA)同时添加自然来源亚油酸(葵花油)对奶牛生产性能的影响。试验期为52d。对照组基础日粮为60%粗饲料(苜蓿、羊草、青贮)和40%精料(以DM为基础),处理组在对照组日粮基础上分别添加Ca-CLA100g/d·头(CLA)、葵花油350g/d·头(Sunf);Ca-CLA100g/d·头 葵花油350g/d·头(CLA Sunf),Ca-CLA50g/d·头 葵花油175g/d·头(1/2CLA 1/2Sunf)。结果表明:在奶牛日粮中,单独添加自然来源亚油酸产奶量较对照组差异不显著(P>0.05),而单独添加共轭亚油酸钙盐或与自然来源亚油酸高低不同剂量添加产奶量较对照组都分别显著提高2.20%、9.95%、11.16%,无论单独添加自然来源亚油酸或Ca-CLA或二者以高低不同剂量同时添加,牛奶的乳脂率较对照组都分别显著降低15.0%,6.24%,21.74%,14.35%。总之,奶牛日粮中同时添加Ca-CLA和自然来源亚油酸能显著提高产奶量,降低乳脂率,并且,减少Ca-CLA的添加量同时添加自然来源亚油酸可以达到高剂量添加Ca-CLA相同的效果。     

影响牛奶trans11C18∶1和CLA合成的因素

乳脂肪受日粮因素的调控的可塑性大，CLA是乳脂肪中的一种微量不饱和脂肪酸，影响乳脂肪的物理和生物学特性。CLA最初发现于奶牛瘤胃，但牛奶中CLA主要通过乳腺组织Δ9去饱和酶作用于trans11C18∶1而内源合成。研究结果表明，日粮因素、动物个体间的差异和动物组织间SCD酶活性的差异是影响乳脂CLA合成的关键因素。作者针对影响trans11C18∶1和Δ9去饱和酶的因素对CLA合成调控因素作了简要论述。     

牛乳脂共轭亚油酸的合成及其营养调控

共轭亚油酸(CLA)是存在于动物脂肪和乳脂中的天然活性成分。本文综述了牛乳脂CLA的来源、合成机制及其营养调控。     

Energy balance of conjugated linoleic acid-treated pigs

The term conjugated linoleic acid (CLA) refers to a group of linoleic acid derivatives whose conjugated double-binding system begins at the carbon atom 8 to 11. This means that including the cis-trans geometry, 16 isomers are possible in theory. CLA occurs primarily in lipids of ruminants because polyunsaturated fatty acids can be converted to CLA in the rumen of these animals through the action of bacterial enzymes (Kepler et al. 1966). The most widely occurring isomer is C18 : 2 c 9, t 11, which is present in milk and dairy products in concentrations of 0.4–1.7% (Fritsche and Steinhart 1998). But CLA was also generated in the colon of rats fed a diet containing free linoleic acid (Chin et al. 1994b). In animal experiments CLA inhibits carcinogenesis and reduces the development of arteriosclerosis (Ip et al. 1994; Belury 1995; Jahreis and Bochmann 1998), and was found to have a specific influence on body composition. In experiments with mice, pigs and chicks a negative effect of CLA on the accumulation of body fat was observed (Pariza et al. 1996; Dugan et al. 1997; Park et al. 1997; West et al. 1998). The effective dose in those experimental diets was 0.5 to 1.5% CLA. In contrast, CLA may also act as a growth factor and increased daily weight gains of rats (Chin et al. 1994a). However, in these trials on changes in body composition the feed intake was not controlled and the observed effects may be due at least partially to differences in feed intake between the control group and the CLA animals. The objective of the present study was to investigate the influence of CLA on thermogenesis and energy balance in animals with an isoenergetic feed intake by using the methodology of the calorimetric balance technique. The animals used in the model were adult sows with a nutritional status approaching equilibrium.     

营养调控对瘤胃及羊乳和羊肉中共轭亚油酸含量影响的研究进展

共轭亚油酸(CLA)因具有抗癌、抗糖尿病及增强机体免疫力等功能而备受研究人员关注,近年来,针对备受消费者青睐的羊肉和羊奶等产品中CLA含量的研究越来越多。作者简述了反刍动物产品中CLA生物合成机制,并重点回顾了多种营养调控措施对瘤胃中CLA和十八碳烯酸积累的影响结果;进一步探讨了这几种营养调控方式对羊乳和羊肉中CLA含量的影响。分析认为,利用油脂底物和调控剂混合添加有利于加强瘤胃纤维菌群和原虫区系对CLA、十八碳烯酸的积累和过瘤胃率,并可在提高动物产品中CLA含量的同时,避免乳脂率下降。今后还需通过营养、分子生物学及生理学等角度全面揭示CLA合成机理,为生产富含CLA的动物产品提供参考。     

Research Progress of Nutrition Regulation on Conjugated Linoleic Acid in Rumen,Goat's Milk and Mutton

Researcher pay attention to the conjugated linoleic acid (CLA) because of its function of anticancer,antidiabetic and immunological competence in the body.A lot of researches on contents of CLA in goat that enjoy high favor among people has been carried out in recent years.The article presents the biosynthsis process of CLA in ruminal,and focus on reviewing the result of many sdudies on the effects of the contents of CLA and vaccine acid in rumen;Further treat of the effects of nutrition regulation on CLA in goat's milk and mutton.Result show that the microflora and protozoa could increase the contents of CLA in rumen by using grease mixed of regulator,and increasing the contents of CLA in animal products at the same time,and avoiding to decline the contents of milk fat.we should reveal synthesis mechanism of CLA through nutrition,molecular biology,and physiology fully in the future,to provides a theoretical basis for producting CLA-enriched mutton and milk.     

牦牛乳及乳制品、犏牛和黑白花奶牛乳的脂肪酸组成分析

用气相色谱 质谱联用仪(GC MS)对牦牛乳、黑白花奶牛乳、犏牛乳及牦牛乳制品（奶油、酥油、曲拉、酸奶）中的脂肪酸组成进行了测定。结果表明,牦牛乳中功能性脂肪酸,如共轭亚油酸（CLA）、亚油酸（LA）、α 亚麻酸（ALA）、γ 亚麻酸（GLA）占总脂肪酸的比重均显著高于犏牛乳和黑白花奶牛乳（P＜0.05）;犏牛乳中ω 6/ω 3 PUFA的比值（1.55）略高于牦牛乳（1.54）,差异不显著（P＞0.05）,但都在最佳膳食平衡比值范围内,黑白花奶牛乳中ω 6/ω 3多不饱和脂肪酸（PUFA）的比值（11.33）超过了推荐最佳比值。加工处理能够改变乳制品脂肪酸的构成,如牦牛乳奶油中检测出原奶中所不含的一种亚油酸（18:2Δ8c,11c）。酥油主要以不饱和脂肪酸（UFA）为主,而曲拉主要以饱和脂肪酸（SFA）为主,牦牛酸奶中没有检测到GLA。     

REVIEWS: Conjugated Linoleic Acid: Historical Context and Implications

Conjugated linoleic acids (CLA) are implicated as anti-carcinogenic, anti-atherosclerosis, and anti-inflammatory agents in a variety of experimental model systems. However, evidence of dietary CLA protection against human mammary cancer risk is mixed and comes from European countries where the death rate from mammary cancer is relatively scarce. Unfortunately, epidemiological data are inconclusive, especially from retrospective studies. Prospective human study evidence will take more time. European values as great as 1.9% CLA in the fat of milk products from grass-fed ruminants has been reported; ordinary monogastric meat and egg products contain substantially less CLA in fat (0.3%). It is now recognized that the principle CLA in ruminant meat and milk is the natural diene, cis (c)-9, trans (t)-11 isomer (rumenic acid) of C18:2 (octadecadienoic acid). Another isomer, C18:2 t-10, c-12, also contributes to the unique biological activity of CLA, but does not readily accumulate in ruminant lipids and is found only in commercial preparations of mixed CLA isomers. Evidence in humans suggested that the role of the dietary mixed isomer CLA in the loss of body fat mass (BFM) was only modest compared with the results from animal model studies, and urine metabolites of prostaglandin F_2α (PGF_2α), indicative of lipid oxidation stress, have been elevated during supplementation. In addition, the fatty acid C18:1 t-11 (vaccenic) is now believed to be the principle precursor of endogenous c-9, t-11 CLA in both ruminants and monogastrics. This finding helps explain the discrepancy between measured c-9, t-11 CLA originating from the rumen and that secreted in cow’s milk. Manipulation of ruminant meat and milk by feeding marine or vegetable oils is clearly associated with increases in vaccenic acid as well. This relationship requires a re-examination of human foods for vaccenic acid content and quantitative measures of CLA endogenous synthesis in humans as well to formulate dietary strategies to capture CLA’s potential protective health benefits.