奶牛正常乳与隐性乳房炎乳中脂肪酸组成的比较研究

旨在研究奶牛隐性乳房炎导致产奶量下降和乳成分的变化.使用气相色谱仪测定57头荷斯坦奶牛(其中32头患隐性乳房炎)乳中脂肪酸组分,比较正常乳和隐性乳房炎乳中脂肪酸的组分.结果表明:共检出21种脂肪酸,隐性乳房炎乳中棕榈油酸(C16:1)的含量高于正常乳,其他20种脂肪酸均低于正常乳,其中有9种显著低于正常乳(P<0.05),2种极显著低于正常乳(P<0.01);隐性乳房炎降低了牛奶中脂肪酸的总含量及饱和脂肪酸、单不饱和脂肪酸和多不饱和脂肪酸的含量;隐性乳房炎乳中饱和脂肪酸和单不饱和脂肪酸的百分比高于正常乳,多不饱和脂肪酸的百分比则低于正常乳.结果提示,隐性乳房炎影响奶牛脂肪酸合成过程,改变了脂肪酸的组分.     

西农萨能奶山羊乳脂肪酸性状影响因素分析

本研究旨在解析母羊出生年度、季节、胎次、泌乳阶段4个固定效应对西农萨能奶山羊乳脂肪酸性状的影响。选择2010—2017年出生的104只泌乳奶山羊,采用气相色谱仪测定实验个体羊奶中37种不同乳脂肪酸含量,采用固定效应模型,通过SAS 9.4软件的GLM过程进行统计分析。结果表明:西农萨能奶山羊乳脂肪酸以C16:0、C18:1n9c、C14:0、C18:0和C10:0为主,其中含量最高的为C16:0,达26.65%;饱和脂肪酸:不饱和脂肪酸为2.27:1,其中,单不饱和脂肪酸:多不饱和脂肪酸为15.52:1;泌乳阶段效应对乳脂肪酸含量影响显著,年度、季节、胎次效应对于乳脂肪酸组分影响较小。研究结果显示,泌乳阶段是影响西农萨能奶山羊乳脂肪酸性状的主要非遗传因素之一,泌乳早期的乳品质更优。     

绵羊初乳和常乳中乳脂肪酸组成的变化研究

利用气相色谱法检测冬季绵羊初乳和常乳中70种C4-C24脂肪酸随时间的变化情况。初乳中单不饱和脂肪酸、多不饱和脂肪酸和C14-C16直链饱和脂肪酸含量高于常乳,而C4-C12、C18及C15-C17支链饱和脂肪酸含量却低于常乳。绵羊品种对于其乳中脂肪酸分布无影响。产羔后1～2d即初乳形成时,乳中脂肪酸组成发生显著变化。在泌乳第6天,乳中脂肪含量持续升高,而在此之后的第60天内乳脂肪含量上升缓慢。这与推荐大家在绵羊泌乳后6～8d食用羊奶的建议一致。与常乳相比,初乳中棕榈酸和豆蔻酸含量偏高,表明初乳的脂肪酸组成可以满足羔羊生长过程中不断变化的需要。     

金黄色葡萄球菌诱导型乳腺炎对中国荷斯坦奶牛乳中脂肪酸组成的影响

本文旨在研究金黄色葡萄球菌诱导型乳腺炎对中国荷斯坦奶牛乳中脂肪酸组成及其绝对含量的影响。根据奶牛乳房结构,试验组利用通乳针将金黄色葡萄球菌细菌悬液经乳头管注射入奶牛乳房内,建立诱导型金黄色葡萄球菌型乳腺炎模型,对照组灌注磷酸盐缓冲液,采用气相色谱法测定乳中的脂肪酸绝对含量。结果表明:乳中共检出34种脂肪酸,金黄色葡萄球菌诱导对感染乳区脂肪酸合成产生直接影响。按不饱和度和碳链长度划分的6大类脂肪酸中,试验组在感染后11 h与感染前24 h相比,短链脂肪酸、中链脂肪酸和饱和脂肪酸的绝对含量均显著降低(P0.05);对照组有相同变化趋势,但除短链脂肪酸外均未达到显著水平(P0.05)。感染后23 h试验组6大类脂肪酸的绝对含量均低于对照组。结果提示:金黄色葡萄球菌诱导型乳腺炎影响了奶牛脂肪酸的合成过程,降低了脂肪酸各组分的绝对含量。     

瘤胃十八碳不饱和脂肪酸氢化的研究进展

瘤胃微生物对不饱和脂肪酸的生物氢化作用,限制了其转化效率,使乳脂肪酸组成的调控难以达到理想的效果。不饱和脂肪酸对微生物生长的抑制是氢化的主要原因;氢化的程度主要由瘤胃内环境决定,如瘤胃pH、金属离子浓度等,脂肪酸来源、水平、脂肪酸之间的相互作用以及其他营养因素等均会对脂肪酸的氢化造成影响。本文主要综述了反刍动物饲料中不饱和脂肪酸氢化的过程、氢化相关瘤胃微生物以及影响氢化程度的因素,同时探讨了营养途径调控氢化的方法,为进一步调控乳脂肪酸组成提供依据。     

牦牛乳脂肪酸含量受海拔和胎次影响

我国科学家的研究结果显示：牦牛乳脂肪酸组分受胎次的影响,并报道了不同海拔牦牛乳脂肪酸的变化,大部分脂肪酸组分是相似的,主要是共轭亚油酸含量在不同海拔问存在变化,     

添加不同脂类对奶牛采食量、消化率、乳产量和乳成分的影响

本文主要综述添加各种脂类对干物质采食量(DMI)、纤维素消化率、乳产量和乳成分的影响,重点概述乳中乳脂及乳脂肪酸组成尤其是不饱和脂肪酸的变化。     

丹宁作为饲料添加剂对瘤胃氢化过程的调控:奶山羊日粮中添加葵花油对其生产性能、乳脂成分及瘤胃发酵的影响

体外试验说明添加丹宁能改变日粮中亚油酸在瘤胃中的氢化过程,使t-11C18∶1(VA,异油酸)在瘤胃中的累积,增加反刍动物副产品中有益脂肪酸如c-9,t-11C18∶2(瘤胃酸,RA)的含量。但对于酚类物质对乳中脂肪酸成分影响研究很少而且结果各异。本试验用14只泌乳中期的奶山羊研究在含有葵花油的日粮中添加两种酿酒物的混合物如白坚木皮提取的丹宁(CT)和栗木单宁酸(HT)对动物生产性能、乳产量和乳成分及瘤胃发酵的影响。所有动物的日粮为精粗比为40∶60的全混合日粮,日粮中添加葵花油20g/kg(干物质基础),试验处理:①对照组:不添加丹宁(试验动物为7头);②处理组(TAN):添加丹宁10g/kg(干物质基础)(试验动物为7只)。试验第0、3、6、9、12、15、18、21、24天采集乳样分析乳成分,试验第0、3、6、12、18、27天分析乳样中脂肪酸成分。试验结果表明,干物质采食量、乳产量、乳成分不受TAN影响。类似,在含有葵花油的日粮中添加丹宁提取物也不会改变牛奶中主要的脂肪酸(如饱和度,单不饱和脂肪酸和多不饱和脂肪酸),也不会改变特殊脂肪酸的含量及不会增加乳中异油酸及瘤胃酸的含量。添加葵花油使乳中脂肪酸如...     

中国荷斯坦牛一个完整泌乳期中乳脂肪酸变化规律研究

为了优化生鲜乳中脂肪酸的组成与比例,提高牛奶品质,试验采用气相色谱技术,测定了南方荷斯坦奶牛一个完整泌乳期原料乳中的脂肪酸组成和含量。结果表明:检出C4~C24共计34种脂肪酸,按饱和度和碳链长度划分,饱和脂肪酸(SFA)、单不饱和脂肪酸(MUFA)、多不饱和脂肪酸(PUFA)的比值约为68∶27∶5,短链脂肪酸(sc-FA)、中链脂肪酸(mc-FA)、长链脂肪酸(lc-FA)的比值约为3∶21∶76。除C15∶0、C18∶2t、C20∶0和PUFA外,测定月份对样品乳中其他脂肪酸含量均有显著影响(P0.05);泌乳月对总SFA含量及总MUFA含量均有显著影响(P0.05),但对总PUFA含量的影响不显著(P0.05);泌乳月对mc-FA和lc-FA含量均有极显著影响(P0.01),而对sc-FA含量的影响不显著(P0.05)。     

驴乳脂肪酸组成与人乳及牛乳的分析比较

本研究以驴乳为研究对象,采用气相色谱法分析测定了其脂肪酸组成,分析比较了驴乳、人乳和牛乳的脂肪酸成分.驴乳中不饱和脂肪酸达到62.9%,牛乳以饱和脂肪酸为主.约占68.0%.驴乳的脂肪酸组成与人乳比较接近,是一种优质的脂类资源.     

Interactions between dietary fatty acids and hepatic gene expression in livers of pigs during the weaning period

The aim of the present study was to evaluate the impact of dietary fatty acids (FA) during the weaning period on expression of genes involved in the oxidation and metabolism of FA (peroxisome proliferator-activated receptor (PPAR-), stearoyl-CoA-desaturase (SCD), Δ6-desaturase (D6D), acetyl CoA carboxylase (ACC) and fatty acid synthase (FAS)). Liver samples were obtained from littermates, either on day 28 of age just before weaning, or at day 56 after the 4 weeks ad lib. provision of 5% of either animal fat, fish oil or sunflower oil. In conclusion, genes involved in the regulation of FA conversion (SCD, D6D) were influenced by the n-6 to n-3 ratio, whereas the FA oxidation, as indicated by the expression of PPAR-, was highly likely regulated by the hepatic ratio between mono- and poly-unsaturated FA. Furthermore, weaning and/or age affected the hepatic expression of genes involved in FA synthesis and conversion, but not the expression of PPAR-.     

Reporting temporal fluctuations of hepatic C16 and C18 fatty acids during late gestation and early lactation in dromedary camel

Tropical Animal Health and Production - Based on current knowledge, C16 and C18 fatty acids (FA) are considered the most functional FA in hepatic metabolism. Although these FAs have been...     

Effect of supplementation of soy sauce oil and Ca salts of fatty acids on rumen fermentation,milk production and conjugated linoleic acid in milk of dairy cows

Eight cows were used to evaluate the effects of supplementation of soy sauce oil (SO) or Ca salts of fatty acids (FA) on rumen fermentation and milk production. The control diet (CO) consisted mainly of hay, corn silage and a concentrate. In the experimental diets, 400 g/day per cow of SO or FA (soybean oil and rapeseed oil) was supplemented to the CO diet. Experimental period for the three treatments was 14 days, and milk samples were taken during the last 2 days and rumen sample was taken on the last day. Dry matter intake was not affected by the treatments. The number of rumen protozoa at 0 h increased by SO and FA diets. Total volatile fatty acids at 2 h after feeding of SO diet was decreased compared to CO. The milk composition yield did not differ among treatments, although the percentages of fat and protein were decreased by SO and FA diets. The proportions of C8–C16 fatty acids in milk fat decreased, and those of C18 increased by SO and FA diets. The proportion of cis‐9, trans‐11 conjugated linoleic acid in milk fat by SO and FA diets increased by 120% and 135%, respectively. In spite of the slight suppression of rumen fermentation by SO diet, negative effects on feed intake and milk production were not detected.     

动物肝脂肪变性的分子机制

肝脏中脂肪酸代谢平衡的破坏是肝脂肪变性的主要原因,胰岛素和葡萄糖都能独立调控肝脏中脂肪酸的生成,在这些调控中起重要作用的转录因子如SR EBP-1,C hR EBP,PPAR等与肝脂肪变性的发生有紧密联系。     

莱芜猪肌肉脂肪酸组成的发育性变化及其对肉质特性的影响

以40￣90kg6个体重阶段莱芜猪和新莱芜猪为试验对象(n=6),研究肌肉脂肪酸组成的发育性变化及其与肉质特性的关系。结果表明:①随着体重的增大,莱芜猪肌肉总脂含量显著(P<0.01)增加;饱和脂肪酸(SFA)总量的比例有下降的趋势,不饱和脂肪酸(UFA)总量有增加的趋势,但差异不显著;在UFA中,多不饱和脂肪酸(PUFA)总量及亚油酸的比例显著(P<0.01)下降,油酸比例显著(P<0.01)增加;②总体上,莱芜猪肌肉中的SFA+单不饱和脂肪酸总量、总脂、棕榈酸、棕榈烯酸的比例显著高于新莱芜猪,而PUFA总量、硬脂酸、亚油酸、花生烯酸的比例显著(P<0.01)低于新莱芜猪。各体重阶段2个品种间的脂肪酸组成也存在着较大的差异;③莱芜猪肌肉中的PUFA总量与总脂、水分、失水率、大理石纹评分相关显著;总脂与水分、大理石纹相关极显著(P<0.01);SFA、UFA总量与大理石纹呈显著(P<0.05)相关。     

家禽脂肪酸代谢及其在禽蛋中的沉积和营养调控

在肝脏中载脂蛋白作用下,内源合成或外源获取的脂肪酸以甘油三酯的形式同胆固醇及其他脂类组装形成极低密度脂蛋白(VLDL)。VLDL经血液循环到达卵巢,穿过卵母细胞外层屏障后,经卵母细胞受体介导的内吞作用进入卵母细胞发生沉积。而机体的营养状况或饲粮中营养成分的改变可通过影响脂肪酸的从头合成或VLDL结构直接或间接影响禽蛋中脂肪酸的最终沉积。本文阐述了家禽体内脂肪酸的来源、转运与沉积过程,并探讨了脂肪酸代谢及其在禽蛋中沉积的营养调控。     

Dietary fatty acids in gut health: Absorption,metabolism and function

In biological responses, fatty acids (FA) are absorbed and metabolized in the form of substrates for energy production. The molecular structures (number of double bonds and chain length) and composition of dietary FA impact digestion, absorption and metabolism, and the biological roles of FA. Recently, increasing evidence indicates that FA are essentially utilized as an energy source and are signaling molecules that exert physiological activity of gut microbiota and immune responses. In addition, FA could serve as natural ligands for orphan G protein-coupled receptors (GPCR), also called free fatty acid receptors (FFAR), which intertwine metabolic and immune systems via multiple mechanisms. The present review explores the recent findings on FA absorption and its impact on gut health, particularly addressing the mechanism by which dietary FA potentially influences intestinal microbiota and epithelial functions. Also, this work attempts to uncover research ideas for devising future strategies for manipulating the composition of dietary FA to regulate gut health and support a normal immune system for metabolic and immune disorders.     

Changes in molecular species composition of triacylglycerol in subcutaneous fat from beef cattle during fattening

The composition of the molecular species of triacylglycerols (TG) in subcutaneous fat biopsied from Japanese Black steers was studied during the fattening period. An analysis of the fatty acid (FA) composition of the TG showed that palmitic, palmitoleic, stearic and oleic acids were the major FA, together accounting for over 80% of the total FA. The concentrations of C14:0, C16:0 and C18:0 decreased between 10 and 30 months of age, while those of C16:1 c9 and C18:1 c9 increased during the fattening period. The major molecular species among more than 40 compounds were palmitoyl‐dioleoyl‐glycerol (POO) and dipalmitoyl‐oleoyl‐glycerol (PPO). POO showed the highest concentration during the fattening period. The levels of palmitoyl‐oleoyl‐linoleoyl glycerol and some tentatively identified molecular species increased during the fattening period, while the levels of tripalmitoyl, dipalmitoyl‐stearoyl‐glycerol, palmitoyl‐distearoyl and palmitoyl‐stearoyl‐oleoyl‐glycerol decreased with growth. A comparison of the experimental values of TG molecular species with theoretical values derived from the experimental FA contents showed that the FA distribution in TG was non‐random. TG synthesis favors the formation of TG molecular species containing at least one C16 FA, rather than three C18 FA.     

Identification and functional analysis of a novel single nucleotide polymorphism (SNP) in the porcine Toll like receptor (TLR) 5 gene

Nine suckling calves were allowed to afterstimulate their dams at three levels, ad libitum , for 3 min or none, at each suckling meal twice daily in a repeated 3 2 3 Latin square experimental design. Each experimental unit consisted of one cow-calf pair for 6 days. Milk yield was recorded and samples were taken at the morning meal on day 7 by hand-milking one quarter while the calf suckled the other three. Samples were analysed for fat content and 19 fatty acids (FA), summarized in five groups: locally synthesized FA, FA deriving mainly from blood serum (BSFA), saturated FA (SFA), unsaturated FA (USFA) and essential FA (ESFA). Variables were expressed as g g -1 fat, kJ g -1 fat, g kg -1 milk delivered at the recorded suckling meal and kJ kg -1 delivered milk. The only factors affected were milk yield, and BSFA, SFA, USFA and ESFA when related to the delivered milk. The relationship between levels of AS and milk yield was a second-degree polynomial.     

Effect of sunflower, linseed and fish oils on the production of trans fatty acids in vitro

In vitro anaerobic incubations were used to determine the effect of different oils (LO-linseed, SO-sunflower, FO-fish oil) on trans fatty acid production in rumen fluid and to test if combining of monensin (MON) with the oils affects the interactions on trans fatty acid concentrations in mixed cultures of ruminal microorganisms. Two different sources of rumen fluid were used; the inoculum from the sheep fed hay and barley (80:20%)--the inoculum A and the inoculum from the sheep fed alfalfa and barley (80:20 %)--the inoculum B. The analyses showed that inoculum B contained more short chain fatty acids (SCFA), medium chain fatty acids (MCFA) and saturated fatty acids (SFA) than inoculum A. In contrast, inoculum A contained more unsaturated fatty acids (UFA) than inoculum B. The results show, that the oils affected the biohydrogenation of fatty acids (FA) by increasing the concentration of C18:0 (3-7 times) and trans C18:1 isomers (2-9 times). The concentration of two main intermediates of FA biohydrogenation-- cis 9, trans 11 C18:2 (CLA) and trans 11C18:1 (TVA) were increased with the oils, but FO was more efficient than other plant oils on CLA and TVA production.The monensin treatment had similar effect on FA metabolism as the oil treatment in comparison to unincubated control. The interactions of monensin treatment with the oils were characterized with decrease (LO+MON, SO+MON) or increase (FO+MON) of the proportions of C18:0 and trans C18:1 isomers in comparison to oil treatment.The highest concentrations of two main isomers--CLA,TVA were found in the samples containing fish oil and monensin. In conclusion, fish oil treatment and monensin with fish oil treatment was more efficient than other plant oils in the effect on trans fatty acid production (mainly CLA and TVA) in fermentation fluid in vitro.