螺旋藻复合多糖与银杏提取物对小鼠耐缺氧能力的影响

将螺旋藻多糖(PSP)与银杏叶提取物(GBE)按不同比例复合,以每日200mg/kg剂量分别灌服小鼠,给药14d后制作小鼠常压密闭缺氧模型,观察小鼠缺氧存活时间,检测心、肝、脑组织MDA含量,肝、脾SOD活力等生化指标。结果表明,供试药物均可延长小鼠在常压密闭缺氧条件下的存活时间,提高缺氧小鼠肝、脾SOD活力,降低缺氧小鼠心、肝、脑组织MDA含量。说明本试验的供试药物均具有一定的抗疲劳作用。PSP与GBE以2∶1比例复合使用对提高小鼠的抗疲劳能力能产生较好的协同增效作用。     

1～21日龄黄羽肉鸡钠、氯的需要量

本试验旨在通过研究饲粮不同钠、氯水平对黄羽肉鸡生长性能、排泄物含水率、血清指标、肠道钠-葡萄糖共转运载体1(SGLT1)和钠/氢交换载体2(NHE2)mRNA表达量等的影响,探讨1~21日龄阶段黄羽肉鸡钠和氯的需要量及其作用机理。试验选用1日龄健康、发育良好的快大型岭南黄羽肉公鸡共1 200只,根据体重随机分成5个组,每组6个重复,每个重复40只鸡。对照组采用玉米-豆粕型基础饲粮(无额外钠、氯添加),其余各组都以钠、氯含量比1∶1设梯度,通过食盐与碳酸氢钠等量取代部分沸石粉使饲粮钠与氯含量均分别为0.1%、0.2%、0.3%和0.4%,试验期间试鸡自由采食和饮水。试验结果显示,饲粮补充钠、氯显著提高了平均日增重、平均日采食量、平均日饮水量和排泄物含水率(P0.05),显著降低了料重比和死亡率(P0.05),其中平均日增重随饲粮钠、氯水平的提高呈二次折线升高(R2=0.966,P=0.009),排泄物含水率随饲粮钠、氯水平的提高呈先升高后降低的二次曲线变化(R2=0.954,P=0.046);饲粮补充钠、氯显著提高了血清渗透压(P0.05),显著降低了血清尿酸、葡萄糖、总胆固醇和甘油三酯含量(P0.05),对血清胆囊收缩素、胃饥饿素和生长激素含量无显著影响(P0.05);饲粮钠、氯水平均为0.2%、0.4%组十二指肠NHE2 mRNA表达量和钠-钾ATP(Na+-K+-ATP)酶活性显著低于对照组(P0.05);饲粮钠、氯水平为0.2%组回肠SGLT1 mRNA表达量显著高于对照组和0.4%组(P0.05)。结果提示,本试验条件下,以生长性能为评定指标,根据方差分析和多重比较得到,1~21日龄阶段快大型黄羽肉鸡饲粮适宜钠、氯水平均为0.2%;通过非线性回归模型估测得到,饲粮适宜钠、氯水平均为0.14%。     

CARDIAC MAGNETIC RESONANCE IMAGING OF PATENT DUCTUS ARTERIOSUS IN THREE DOGS

Patent ductus arteriosus (PDA) is the most common congenital cardiovascular disorder in dogs and requires an accurate diagnosis for an appropriate treatment. Cardiac MRI (cMRI) has been reported as a method for characterization of canine thoracic vasculature. However, to the authors’ knowledge, no published studies describe evaluation of canine PDA through cMRI. Three dogs were selected for this exploratory study. Electrocardiogram gating and breath‐hold techniques were performed using a 3T MR scanner. Both black blood imaging and bright blood cine acquisitions were performed. Quantification of stroke volume (SV) and shunting volume were calculated using a stack of short‐axis cine images. Additional 4D (three‐spatial dimensions plus time)‐TRAK (time‐resolved MR angiography with keyhole) sequences were conducted in patient 2 to verify other vasculature abnormality. Black blood images clearly depicted the course of the ductus from the descending aorta to the pulmonary artery in all three dogs. Morphological evaluation of PDA classified patients 1 and 2 as Type 2a and patient 3 as Type 1. Patient 2 was confirmed to have a concurrent persistent left cranial vena cava. Left ventricular SV, right ventricular SV, and left‐to‐right SV ratio were 12.4 ml, 3.36 ml, and 3.704, respectively, in patient 1; 6.85 ml, 1.22 ml, and 5.60 in the patient 2; and 3.67 ml, 2.14 ml, and 1.702 in patient 3. Findings indicated that cMRI is a feasible method for characterizing the morphology of PDA and extracardiac vasculature anomalies in dogs.     

Research Advances in Escherichia coli K1 Penetration Across Blood-brain Barrier

E.coli K1 strain is a representative strain of neonatal sepsis and meningitis, which causes disease by blood circulation to the brain. The molecular mechanism of E.coli K1 that adhering and invading the brain microvascular endothelial cells (BMECs) and cross the blood brain barrier (BBB) has been focused on by many scholars. In this review, we focused on the gene regulation mechanisms and signaling pathway of E.coli K1 crossing the blood brain barrier to understand the molecular mechanism of the infection caused by E.coli and provide reference for prevention and treatment programs.     

Investigation and Analysis of Porcine Epidemic Diarrhea Virus,Transmissible Gastroenteritis Virus and Pseudorabies Virus of Swine Diarrhea Cases in Shandong Province

To understand porcine viral diarrhea prevalence in the large-scale pig farms of Shandong province, a total of 3 035 clinical samples were detected by PCR from January, 2014 to December, 2016.Those samples were detected for porcine epidemic diarrhea virus (PEDV), transmissible gastroenteritis virus (TGEV) and pseudorabies virus (PRV). The results showed that the detection rate of PEDV, PRV and TGEV were 67.49%, 9.33% and 3.29%, respectively.During the past three years, the lowest detection rate of PEDV was 48.15% in the fourth quarter of 2014,and the highest was 88.57% in the fourth quarter of 2015.In 2016,the detection rate represented fluctuate declining compared with 2015.The highest positive rate of TGEV was 18.52% in the fourth quarter of 2014,and in the third quarter of 2015 was 15.38%.The lowest positive rate of TGEV was 6.67% in the first quarter of 2016 and TGEV was not detected in the other quarters. The highest detection rate of RPV was 15.68% in the second quarter of 2016,and the lowest was 2.56% in the second quarter of 2014,except the first quarter of 2014 that the PRV was 0. By detecting three kinds of viruses in 69 clinical samples collected passively, the results showed that the detection rate of PEDV,TGEV and PRV were 86.96%,5.80% and 37.68%,respectively. The total single infection rate was 69.57%,the single infection rates of PEDV,TGEV and PRV were 57.97%,1.45% and 10.14%, respectively;The total mixed infection rate was 30.43%,the mixed infection rates of PEDV/PRV,PEDV/TGEV and TGEV/PRV were 26.09%,2.90% and 1.45%, respectively;Obviously, the total single infection rate was higher than the total mixed infection rate. The results showed that the PEDV, PRV and TGEV were prevailing in Shandong province. There were PEDV/TGEV, TGEV/PRV, PEDV/PRV mixed infection, and the number of PEDV/PRV mixed infection was in the majority. However, there was no PEDV/PRV/TGEV mixed type infection. At present, PEDV was the major pathogen of porcine viral diarrhea and the test results could provide the reference to the diagnosis of porcine viral diarrhea.     

鸭致病性大肠杆菌分离鉴定及其相关致病性分析

为研究鸭大肠杆菌的致病性及相关生物特性,本试验从西昌市某规模化鸭场采集病料,通过传统分离培养及理化性质鉴定,分离得到27株鸭致病性大肠杆菌。对27株鸭致病性大肠杆菌进行血清型鉴定、药敏试验、相关毒力基因检测。血清型鉴定结果显示,优势血清型为O119、O86、O126、O142和O44,占分离株55.56%。血清型O119占27株鸭致病性大肠杆菌的40.74%,为该鸭场流行的致病血清型。对20种兽医临床常用药物的药敏试验结果显示,27株鸭致病性大肠杆菌均对阿米卡星、庆大霉素和多黏菌素B敏感,对头孢曲松等10种药物较敏感,对利福平等5种药物耐受。大肠杆菌相关毒力基因检测结果显示, iutA、hlyF、Iss、IroN、ompT、fyuA、irp 2、Tsh及papA基因携带率均为100.00%, fimC基因携带率59.26%, K 99基因携带率7.40%。各项研究结果为有效防控鸭大肠杆菌病提供了重要科学依据,并为大肠杆菌深入研究奠定了基础。     

辽宁地区奶牛乳房炎细菌性病原分离鉴定及大肠杆菌药敏试验

为了掌握辽宁地区奶牛乳房炎主要细菌性病原种类及致奶牛乳房炎大肠杆菌药物敏感性特征,本研究选取辽宁地区某大型奶牛场75头临床表现为乳房炎的奶样进行细菌培养与分离,通过生化方法对分离到的细菌进行鉴定,并对分离到的奶牛源大肠杆菌进行体外药物敏感性试验研究。结果发现,该场奶牛乳房炎细菌性病原主要为大肠杆菌、葡萄球菌和链球菌,其检出率分别为58.7%、64.0%和54.7%,存在二重感染和三重感染等混合感染的情况。大肠杆菌药物敏感性试验结果表明,该场分离株对磺胺类药物（耐药率>85%）及氯霉素类药物（耐药率>30%）耐药性较高,对氨苄西林（9.5%）、环丙沙星（9.5%）、头孢噻呋（7.1%）和氧氟沙星（4.8%）比较敏感。上述研究结果为该地区奶牛乳房炎的防制提供可靠的理论依据。     

乳粉表面脂肪在生产和贮存过程中的变化及对功能特性的影响研究进展

喷雾干燥是目前食品工业最常用的干燥方式之一.乳浓缩物经过喷雾干燥后获得乳粉,在乳粉颗粒表面也存在着乳脂肪.经研究,乳粉颗粒表面脂肪与乳粉内部脂肪和总脂肪的含量及分布有所不同.本文主要介绍了乳粉颗粒表面脂肪的性质,不同的喷雾干燥条件对于乳粉颗粒表面的脂肪成分的影响以及加工过程中和贮藏后乳粉表面脂肪的变化;同时对乳粉表面游离脂肪脱去前、后乳粉的一系列性质进行对比.     

Whole-plant Corn Silage Quality Treated with Mixed Acids and its Effect on Sheep Growth Performance

In order to explore different concentrations of mixed acids in improving quality of whole-plant corn silage and their effects on growth performance of Dorper×Han F1 sheep.4 levels of 45% formic acid,45% propionic acid and 10% sodium propionate were mixed,and 0(control),0.3%,0.6% and 1% were added to 4 groups of ripening period whole-plant corn.The results showed that compared with control group,the experimental groups could significantly decrease the proportion of AA/PA in silage (P<0.05);0.3% and 0.6% groups had the better effects.Based on the result of CNCPS,0.6% group significantly improved the PB₃ component (P<0.05),reduced the CC component (P>0.05),and improved the quality of silage.Compared with control group,the experimental groups effectively inhibited the mold and yeast reproduction,improved the aerobic stability of silage.The feeding trial results showed that ADG and F/G of sheep in experimental groups were better than control group,and F/G of both 0.6% and 1% groups were significantly better than that in control group (P<0.05).In conclusion,treatment of mixed acids could improve the quality of whole-plant corn silage,and silage treated with 0.6% levels of mixed acids could significantly improve the growth performance of Dorper×Han F1 sheep.