奶牛脂肪肝的病理学研究进展

脂肪肝是许多奶牛泌乳早期主要的代谢性疾病,并常引起奶牛疾病的发生和繁殖力下降.严重的病例,泌乳量和能量摄入减少.因此,病理学研究可为脂肪肝的预防和治疗提供有利的理论基础,每年可节省数百万美元的损失.脂肪肝是由于肝脏摄取脂类的量超过肝脏氧化和吸收的量,脂肪动员高浓度的血浆非酯化脂肪酸引起的.过量的脂肪以甘油三酯的形式储存于肝脏,造成细胞完整性和功能降低,从而造成肝脏功能改变.文章从脂肪肝的基础病理、临床病理、免疫病理以及生殖病理方面,论述了脂肪肝的病理学研究进展.     

An Abattoir Survey on the Frequency of Fatty Liver Syndrome in Dairy Cows from the Suburbs of Tehran

One hundred and six Holstein and Holstein x native cows were inspected before and after slaughter, and liver samples were taken. The fat content of all the liver samples was estimated by an extraction method (Soxhlet). The livers of 29 cows (27%) were classified as fatty. Seventeen of the animals were newly calved, 47 were non-pregnant, 33 were pregnant and 9 were dry, the median values for the fat content of their livers being 60.6, 34.4, 34.7 and 33.8 mg/g, respectively. The median concentration of liver fat in the first group was significantly different from that in each of the other groups (p < 0.01).     

Effects of Pueraria on Biochemical Indexes of Fatty Liver Hepatocytes in Dairy Cows

To explore the acting mechanism of Pueraria extract on fatty liver hepatocytes in dairy cows. The hepatocytes in dairy cows were isolated by two-step collagenase perfusion method and observed. The hepatocytes cultured in vitro were treated with different concentrations of Pueraria extract. The activities and contents of ALT, AST, TG, SOD and MDA in the hepatocytes were detected by biochemical methods. Results showed that in the administration of Pueraria extract with the concentrations of 50,100 and 500 μg/mL could extremely significantly reduce the liver cells of ALT, AST, TG, TC, MDA activity and content, increase SOD activity (P < 0.01). The Pueraria extract had significantly therapeutic effect on dairy cows fatty liver of biochemical indexes. The mechanism might be related to regulate lipid metabolism and anti lipid peroxidation.     

葛根对奶牛脂肪肝细胞生化指标的影响

为探讨葛根对奶牛脂肪肝细胞的作用机制,采用胶原酶二步灌流法分离病牛的肝细胞,并观察细胞形态。用不同浓度的葛根水提物处理肝细胞,生化法检测细胞上清液中丙氨酸氨基转移酶（ALT）、天门冬氨酸氨基转移酶（AST）活性,并测定细胞裂解液中甘油三酯（TG）、胆固醇（TC）、丙二醛（MDA）、超氧化物歧化酶（SOD）的活性及含量。结果显示,50、100、500 μg/mL葛根水提物能极显著降低肝细胞中ALT、AST、TG、TC、MDA活性及含量,增加SOD活性（P < 0.01）。葛根水提物能显著改善肝细胞的相关生化指标,其机制可能与调节脂质代谢、抗脂质过氧化作用相关。     

代谢组学技术在筛选奶牛脂肪肝生物标志物中的应用研究进展

脂肪肝是奶牛养殖过程中一种高发的营养代谢性紊乱病,会降低奶牛产奶量和平均使用寿命,影响后续生产性能的发挥,给奶牛养殖业造成巨大经济损失。组学技术的应用已经成为奶牛疾病研究的重要手段,可为预防和治疗奶牛脂肪肝提供理论基础和技术支撑。综述了代谢组学技术在筛选奶牛脂肪肝生物标志物中的应用研究进展,以期为生产实践中快速诊断和治疗奶牛脂肪肝提供参考。     

Activity of hepatic but not skeletal muscle carnitine palmitoyltransferase enzyme is depressed by intravenous glucose infusions in lactating dairy cows*

A positive energy balance in dairy cows pre‐partum may decrease hepatic carnitine palmitoyltransferase (CPT) enzyme activity, which might contribute to disturbances of lipid metabolism post‐partum. The purpose of this study was to investigate whether skeletal muscle CPT activity can also be downregulated during positive energy balance. Mid‐lactating dairy cows were maintained on intravenous infusion of either saline (control) or glucose solutions that increased linearly over 24 days, remained at the 24‐day level until day 28 and were suspended thereafter. Liver and skeletal muscle biopsies, as well as four diurnal blood samples, were taken on days 0, 8, 16, 24, and 32, representing infusion levels equivalent to 0%, 10%, 20%, 30% and 0% of the net energy for lactation (NE_L) requirement respectively. Glucose infusion increased serum insulin concentrations on day 16 and 24 while plasma glucose levels were increased at only a single time point on day 24. Serum beta‐hydroxybutyric acid concentrations decreased between day 8 and 24; whereas changes in non‐esterified fatty acids were mostly insignificant. Total lipid contents of liver and skeletal muscle were not affected by treatment. Hepatic CPT activity decreased with glucose infusion (by 35% on day 24) and remained decreased on day 32. Hepatic expression levels of CPT‐1A and CPT‐2 mRNA were not significantly altered but tended to reflect the changes in enzyme activity. In contrast to the liver, no effect of glucose infusion was observed on skeletal muscle CPT activity. We conclude that suppression of CPT activity by positive energy balance appears to be specific for the liver in mid‐lactating dairy cows.     

The activity of lecithin: Cholesterol acyltransferase in the serum of cows at parturition or with fatty liver

The activity of lecithin: cholesterol acyltransferase (LCAT), which is responsible for esterification of plasma cholesterol, was evaluated in bovine serum. It was associated with the high-density lipoprotein fraction that contains apolipoprotein A–I, an activator of LCAT. In lactating cows, the activity was around 1000 U (decrease in nmol of free cholesterol per h per ml of serum), slightly higher than in 1-month-old calves. LCAT activity decreased around parturition, at which the time the serum concentrations of cholesteryl esters and free cholesterol were concomitantly decreased. A reduced LCAT activity was also found in cows with fatty livers induced by the administration of ethionine. In the cows with fatty livers, the serum concentration of cholesteryl esters was markedly decreased, whereas that of free cholesterol was only slightly decreased, thereby increasing the free- to esterified-cholesterol ratio. These results suggest that the decrease in LCAT activity may be involved in the reduction in fertility associated with fatty liver because esterification of cholesterol by LCAT is essential for its transport from the liver to peripheral tissues, such as the corpus luteum, and because cholesterol serves as the source of progesterone synthesis in the latter organ.Abbreviations apoA–I apolipoprotein A–I - CE cholesteryl esters - CM chylomicron - FC free cholesterol - HDL high-density lipoprotein - IDL intermediate-density lipoprotein - LCAT lecithin:cholesterol acyltransferase - LDL low-density lipoprotein - VHDL very high-density lipoprotein - VLDL very low-density lipoprotein     

围产期奶牛脂肪肝生物标志物受试者工作特征曲线分析

【目的】通过受试者工作特征(receiver operating characteristic, ROC)曲线筛选诊断脂肪肝生物标志物的最佳临界值。【方法】随机采集77头产后7 d中国荷斯坦奶牛血清,测定生理生化指标。根据Reid方程计算的Y值将奶牛分为正常组(Y>1)和脂肪肝组(Y<1),比较两组奶牛血清指标的差异,并与Y值进行相关性分析,筛选组间差异与相关性显著的指标作为生物标志物,用ROC曲线评估生物标志物的AUC值、诊断敏感性与特异性和最佳临界值。将Reid方程诊断脂肪肝的准确率作为标准,用非酯化脂肪酸(NEFA)、谷草转氨酶(AST)的最佳临界值检测461头奶牛患脂肪肝的情况。【结果】生理生化检测结果表明NEFA、葡萄糖(Glu)、AST、谷丙转氨酶(ALT)在2组间差异极显著(P<0.01),总蛋白(TP)组间差异显著(P<0.05),其他指标两组间无显著差异(P>0.05);NEFA、Glu、AST、ALT、TP、甘油三酯(TG)、低密度脂蛋白胆固醇(LDL-C)、胰岛素(Ins)、胰高血糖素(Gln)与Y值显著相关(P<0.05),可...     

Clinical and Pathological Studies in Cattle with Hepatic Disease

West, H.J., 1997. Clinical and pathological studies in cattle with hepatic disease. Veterinary Research Communications, 21 (3), 169-185In cattle with hepatic lipidosis, hepatic abscessation, leptospirosis, biliary calculi or fasciolosis, the progression of the disease was studied by serial measurements of serum total bile acid concentrations, plasma glutamate dehydrogenase, -glutamyltranserase, 5-nucleotidase and leucine aminopeptidase activities Terminalia avicennioides and by liver biopsy. Regardless of the cause of the hepatic disease, weight loss, anorexia, dullness and depression were consistent features. Signs of hepatic encephalopathy, such as blindness, head pressing, excitability, ataxia and weakness were less common and, together with pyrexia and jaundice, were grave prognostic signs. Plasma ammonia concentrations were significantly elevated compared to clinically normal cattle, but such changes were not always accompanied by a decline in plasma urea concentrations. In normal, healthy cattle, the plasma ammonia:urea concentration ratio is 9:1 and the plasma ammonia:glucose concentration is 11:1. In hepatic disease, a plasma ammonia:glucose ratio >40:1 or plasma ammonia:urea ratio >30:1, particularly with a rising total ketone body concentration and a declining glucose concentration, carried a guarded prognosis. The study suggested that other factors, such as hypokalaemia, alkalosis, short-chain volatile fatty acids, and false and true neuro-transmitters, may be important in the pathogenesis of hepatic coma in cattle.     

鹅肥肝形成相关基因的研究进展

鹅肥肝与鲟鱼子酱、黑菌被西方人誉为世界三大美食。对于肥肝产业而言,加强对鹅遗传育种的研究,培育产肝鹅新品系有着重要的意义。作者依据肥肝形成机制,综述了近年来研究发现的影响肥肝形成的相关基因,包括主要参与脂肪合成的硬脂酰辅酶A去饱和酶(SCD-1)、脂蛋白脂酶(LPL)、脂肪酸合成酶(FAS)、肝X受体(LXRα)、脂肪酸长链延伸因子6(ELOVL-6)、固醇调节元件结合蛋-1c(SREBP-1c)、碳水化合物反应元件结合蛋白(CHREBP)基因,参与脂肪转运的脂肪型脂肪酸结合蛋白(A-FABP)、长链酯酰辅酶A合成酶1(ACSL1)基因,以及参与脂肪氧化的过氧化物酶体增殖物激活受体(PPAR)、胆固醇7a轻化酶(CYP7A1)基因等。     

添加不同脂肪酸对填饲朗德鹅产肝性能、屠宰性能及体脂沉积的影响*

将14周龄、体重相近的健壮朗德鹅120只随机分成6组,每组20只,以玉米作为主要填饲饲料。试验组在对照组日填饲量的基础上分别添加一定量的脂肪酸：6％葵花籽油（葵花籽油组）、6％菜籽油（菜籽油组）、6％牛油（牛油组）、3％鹅油（鹅油Ⅰ组）、2％鹅油（鹅油Ⅱ组）。试验结果表明：添加脂肪酸能影响填饲朗德鹅的产肝性能,其中以葵花籽油效果最好,肝重是对照组的1．37倍,差异显著（P〈0.05）,牛油使填饲朗德鹅产肝下降。添加油脂组对屠宰性能影响不如产肝性能影响明显,菜籽油组在试验中屠宰性能最好且腹脂沉积能力最强,与对照组相比差异显著（P〈0.05）,但是添加脂肪酸组之间差异不显著（P〉0.05）。     

Retained placenta in cattle: the effect of treatment or nontreatment on puerperal diseases and subsequent fertility

In order to examine the effect of treated and untreated retained placenta (RP) on fertility and on the occurrence of puerperal and fertility diseases, the records of 248 cows with RP were examined: 199 cows were treated with intrauterine tetracycline or systemic therapeutics, and 49 were left untreated. One hundred and ninety-six herd mates without RP served as controls. The fertility of the cows with RP was lower than that of the controls. The effect of treatment on fertility was neither beneficial nor harmful. The untreated cows with RP seemed to be treated more often for endometritis and repeat breeding than either the treated animals or the controls. Mastitis within 1 week after calving was more common in both groups of RP cows than in the controls. Most cases of mastitis in the treated RP group could be diagnosed at the time of RP treatment.     

脂肪酸调控奶牛乳腺microRNAs研究进展

脂类是一种可以为动物体储存和提供能量的物质,大量研究证实,日粮中脂类的改变可以改变microRNAs（miRNAs）的表达从而影响机体生命活动。本综述主要概括了脂肪酸对奶牛乳腺miRNAs的调控作用,从奶牛乳腺miRNAs表达特征、调控乳脂合成的miRNAs及外源添加脂肪酸对乳腺miRNAs的调控三个方面进行概述,旨在从转录后调控角度,建立营养物质与乳腺功能的联系,为未来相关研究提供参考。     

Research Progress of Fatty Acid Regulation of microRNAs in Dairy Cow Mammary Glands

Lipids are a kind of substance which can store and provide energy for animals. A large number of studies have confirmed that the change of lipids in diets can alter the expression of microRNAs (miRNAs) and thus affect the biological activities of the bodies. This review mainly summarizes the regulation of fatty acids on the expression of miRNAs in mammary gland of dairy cows, from the aspects of bovine mammary miRNAs expression characteristics, miRNAs that regulate milk fat synthesis, and the changed bovine mammary miRNAs in response to exogenous addition of fatty acids. All these works may be beneficial for the establishment of the connection between nutrients and mammary function, and provide information for the related research in the future.     

用Wood模型拟合四川地区黑白花奶牛泌乳曲线的研究

用四川省阳坪种牛场 1 992年— 1 997年的黑白花奶牛共计 31 2个泌乳期的泌乳曲线 ,以研究胎次、产犊季节、干奶天数和初产年龄四个因素对模型参数估计值的影响。结果表明 :胎次的差异对参数a、b、c影响显著 ,对参数tmax影响不显著 ;产犊季节的差异对参数tmax影响显著 ,对参数a、b、c影响不显著 ;初产年龄的差异对参数a影响显著 ,对参数b、c、tmax影响不显著 ;干奶天数的差异对参数b、c、tmax影响显著 ,对参数a影响不显著 ;此外还给出了Wood模型拟合四川地区黑白花奶牛泌乳曲线的参数估计值     

脂肪酸钙对中国荷斯坦牛干物质采食量产奶量及经济效益影响的研究

选择6头经产、胎次相同或相近、产后10～20天的中国荷斯坦牛,采用3×3重复拉丁方设计,研究脂肪酸钙对中国荷斯坦奶牛泌乳早期的干物质采食量、产奶量的影响.试验处理分别为处理A组为基础日粮;处理B组为基础日粮+200克脂肪酸钙处理C组为基础日粮+400克脂肪酸钙.试验结果表明(1)日添加200克的B组对干物质采食量没有影响(P＞0.05);日添加400克的C组使干物质采食量显著下降,日干物质采食量比对照组下降了1.2千克(P＜0.05).(2)B组日产奶量比对照组提高了2.33千克(P＜0.05),C组产奶量未得到显著提高(P＞0.05);(3)日添加200克脂肪酸钙经济效益显著,每头牛每天可增加纯收入2.90元人民币;400克组从经济效益分析每头每天亏损0.92元人民币.     

奶牛围产期脂肪肝的研究进展

脂肪肝是奶牛围产期常见多发的营养代谢性疾病,特别是高产奶牛的发病率极高,常常伴随难产,并诱发多种炎性反应等疾病.此外,还会导致奶牛产奶量减少和平均寿命降低,给奶牛养殖业带来巨大损失.因此探究围产期奶牛脂肪肝的发展进程,对于切实提升高产奶牛的经济价值,和对奶牛脂肪肝的预防与治疗有着重要意义.本文对奶牛围产期脂肪肝的研究情...     

四川奶牛结核病和布鲁氏菌病的净化示范

为了加快四川省结核病和布鲁氏菌病的净化工作,作者在四川选定了5个奶牛场,开展了奶牛两病净化示范工作。应用γ-干扰素体外释放试验检测结核病,应用ELISA技术诊断布鲁氏菌病,提高了两病的检测准确性。另外,实行全面监测、引种监管、强制隔离、强制消毒、强制扑杀、强化饲草监管等一系列措施,形成了一整套净化方案,从目前的净化效果来看,取得了比较明显的净化效果。     

不同脂肪酸添加比例对荷斯坦新产牛生产性能的影响

通过动物试验对比新产牛日粮中不同脂肪酸添加比例对其泌乳性能的影响。分别选取35 头荷斯坦新产牛作为参试动物,分为试验组I、试验组II和对照组。对照组日粮中不添加脂肪性添加物;试验组I饲喂脂肪酸钙添加剂,其中脂肪酸占比为C16：0∶C18：1=51.00%∶35.00%;试验组II饲喂棕榈脂肪粉添加剂,其中脂肪酸占比为C16：0∶C18：1=80.00%∶8.00%,保证各组日粮的泌乳净能和粗蛋白水平一致。试验全期对照组与试验组II的平均干物质采食量都极显著高于试验组I（P<0.020）,分别增加2.470 kg和2.070 kg,对照组与试验组II间无显著差异。试验全期对照组与试验组II的产奶量都极显著高于试验组I（P<0.020）,分别增加3.560 kg和3.500 kg,对照组与试验组II间无显著差异。对照组、试验组I和试验组II之间的体重无显著差异,试验组II失重最小为64.100 kg,对照组失重最大为87.500 kg,相差23.400 kg。综合分析,日粮中添加脂肪粉（C16：0∶C18：1=80.00%∶8.00%）对产后泌乳性能以及减少产后体脂动员、维持体况最为有利。