实验性流行性腹泻仔猪小肠粘膜上皮细胞及肠系膜淋巴结的超微结构

给8头生后3d的哺乳仔猪经口感染猪流行性腹泻病毒(PEDV)“吉”毒株,于感染后18、30、45和96h各扑杀2头,以透射电镜和扫描电镜观察了小肠粘膜上皮细胞及肠系膜淋巴结的超微结构。结果表明,小肠上皮细胞的病变因感染时间不同而有明显差异。上皮细胞的脱落和残留上皮细胞超微结构的破坏,以感染后30h最严重,病毒在这些上皮细胞内的增殖最显著。感染后45h,见有大量新生上皮细胞修补损伤的肠绒毛。感染后96h,小肠绒毛短缩、粗大乃至发生融合。实验仔猪肠系膜淋巴结内巨噬细胞和淋巴细胞的超微结构均遭到破坏,在巨噬细胞内见有PED冠状病毒粒子。     

新PEDV流行毒株的病理学观察及抗原定位研究

为了加深对猪流行性腹泻病理学损害的认识,试验采用常规石蜡切片及免疫组织化学方法对确诊为变异猪流行性腹泻病毒(Porcine epidemic diarrhea virus,PEDV)引起的患病仔猪主要脏器的病理变化及抗原定位进行了研究。结果表明:猪流行性腹泻患病仔猪胃黏膜脱落,肠系膜肿胀充血、乳糜管消失;小肠绒毛上皮细胞坏死、脱落,肠绒毛缩短,肠壁变薄;肠系膜淋巴结髓质区瘀血出血;小肠绒毛上皮细胞、肠腺细胞、隐窝部位、小肠绒毛固有层和肠系膜淋巴结出现PEDV强阳性表达。说明PEDV的主要靶器官是胃肠黏膜上皮、腺体及相应的淋巴结,而胃、肠等器官的损伤是该病的主要病理变化特征。     

新型仔猪腹泻病的病理组织学观察

对于近几年危害严重的新型仔猪腹泻病的主要脏器进行了病理组织学变化的观察,为该病的发病机理提供理论基础。采集7日龄左右的腹泻病仔猪心脏、肝脏、肾脏、脾脏、小肠进行石蜡包埋,采用H.E.染色方法观察。结果显示,病猪心脏心肌纤维间隙增宽、肌纤维断裂;肝脏淤血、坏死;肾脏充血、肾小管上皮细胞肿胀;脾脏脾小体数量减少,脾动脉周围淋巴鞘变薄;小肠绒毛上皮脱落严重。结果表明,新型仔猪腹泻病可导致机体血液循环障碍及免疫抑制。     

猪流行性腹泻流行病学研究进展

<正>猪流行性腹泻(PED)是由猪流行性腹泻病毒(PEDV)感染引起的一种以急性腹泻、呕吐、严重脱水为主要临床症状的急性、高度传染性、高致死性病毒性肠道传染病。PEDV可感染各年龄段的猪,以哺乳仔猪最易感,经口鼻感染后病毒直接进入小肠,在肠绒毛上皮细胞增殖进而对细胞器造成损伤,导致的细胞功能障碍引起肠黏膜细胞坏死、肠绒毛脱落,从而引起腹泻,脱水,小肠臌气、扩张、积液等临床症状,严重者可导致仔猪死     

A型产气荚膜梭菌感染绿壳蛋鸭的病理发生学研究

为了探究A型产气荚膜梭菌感染鸭后的病理变化情况。选取37日龄健康绿壳蛋鸭灌喂A型产气荚膜梭菌进行人工感染,观察不同时间的临床症状和病理变化。结果:感染72 h后病鸭开始出现腹泻症状,随着时间的增加,临床症状表现越来越明显。96 h后出现褐色粪便,剖检可见部分组织间有纤维素性渗出液。120 h后剖检可见部分组织有出血点。144 h后鸭出现死亡,剖检可见以十二指肠、空肠、回肠的出血点及坏死最为严重,该时期的病理切片观察结果主要为:十二指肠肠腔充满变性、脱落、坏死的上皮细胞,肠绒毛发生崩解脱落并有血细胞和少量炎性细胞浸润,间杂大量淋巴细胞;回肠绒毛总体结构较为完整,部分肠绒毛发生断裂,并伴有充血现象;空肠肠腔充满变性、脱落、坏死的上皮细胞,肠绒毛发生崩解脱落,并有血细胞和少量炎性细胞浸润,肌纤维间隙较大、断裂、密度明显减小。     

仔猪回肠绒毛M细胞的形态、分布及其与猪流行性腹泻病毒感染的关系

为了探索新生仔猪回肠绒毛上皮是否存在M细胞以及自然感染条件下猪流行性腹泻病毒(PEDV)与回肠绒毛M细胞之间的关系。采用免疫荧光、免疫组化及形态学方法研究了正常情况下仔猪回肠绒毛M细胞的分布特点和形态学特征,以及自然感染条件下PEDV与仔猪回肠绒毛M细胞之间的关系。免疫荧光结果证实正常仔猪回肠绒毛上皮存在M细胞,沿隐窝至绒毛顶端上皮方向,M细胞的数量逐渐减少。电镜下,正常仔猪的回肠绒毛M细胞具有典型的M细胞特征。自然感染PEDV的仔猪回肠绒毛M细胞病变明显,在其顶膜、细胞质、细胞核及其上皮下层均观察到成簇的PEDV颗粒,而相邻的其他上皮细胞病变不明显,且细胞内没有观察到病毒粒子。以上研究结果表明,新生仔猪回肠绒毛上皮存在M细胞,在绒毛的不同位置其分布比例存在差异。仔猪回肠绒毛M细胞可能是PEDV入侵肠道的重要通道。     

猪A群轮状病毒SCJY-13株的分离鉴定及致病性分析

【目的】 在从腹泻仔猪粪便中分离鉴定猪A群轮状病毒(Rotavirus group A, RVA)并了解其致病性。【方法】 应用MA-104细胞从仔猪腹泻粪便中分离鉴定RVA, 将其经口感染健康初生仔猪, 观察其临床症状, 并利用实时荧光定量PCR检测排毒、HE染色观察病理变化、免疫组织化学(immunohistochemistry, IHC)试验了解病毒分布。【结果】 分离到1株可引起MA-104细胞明显细胞病变的G9P[23] RVA, 命名为RVA/Pig-tc/CHN/SCJY-13/2017/G9P[23](简称SCJY-13株), 病毒滴度为10^5.5 TCID₅₀/100 μL。经口感染SCJY-13株的仔猪在感染后11 h出现腹泻, 持续到感染后165 h完全恢复, 其发病率为100%(7/7), 病死率为28.57%(2/7)。感染后8 h可从仔猪肛拭子检测到病毒核酸, 直至感染后192 h, 峰值出现在感染后24 h。感染后54 h各段小肠病毒载量达到最高, 其中回肠中病毒载量最高, 显著高于十二指肠、空肠(P<0.05);HE染色和IHC检测结果显示, SCJY-13在感染仔猪小肠的绒毛及隐窝中大量聚集, 尤其是回肠段; SCJY-13株感染引起十二指肠、空肠和回肠绒毛固有层大量淋巴细胞浸润、黏膜上皮细胞和肠绒毛尖端空泡变性、柱状细胞增多、绒毛断裂脱落等, 以回肠段较严重。【结论】 SCJY-13株能引起新生仔猪100%发病, 其主要靶位区在回肠, 感染后排毒时间长。本试验结果为猪RVA的致病性研究提供了一定的参考依据。     

鸡传染性支气管病毒ZZ2004株致SPF感染鸡小肠损伤的病理与超微病变研究

为研究鸡传染性支气管炎病毒(IBV) ZZ2004株引起鸡生长缓慢的发病机理,本实验将100只7日龄SPF雏鸡平均分为两组.实验组经口服病毒进行感染,对照组口服生理盐水,通过临床检查、病理学检查及超微病变观察进行研究.病理解剖学检查表明,实验组鸡各肠段有不同程度卡他性出血性炎性变化.病理组织学显示,小肠绒毛变短,上皮细胞脱落,固有层内炎性细胞增多.扫描电镜观察表明,肠绒毛的游离端常断裂,固有层裸露,在肠上皮细胞之间有大量杯状细胞的开口,并见大块状的分泌物渗出.透射电镜检查显示,残存的肠上皮细胞的微绒毛严重破坏；粗面内质网脱颗粒,滑面内质网明显扩张,呈囊状或泡状,在内质网中出现大量病毒颗粒；核周隙扩张,在核质中能够检出成熟的病毒颗粒.本研究结果表明:IBV ZZ2004株可以在肠上皮细胞中增殖,引起肠的吸收上皮和肠绒毛的一系列退行性病变,从而导致感染鸡代谢障碍,生长缓慢.     

肠艾美耳球虫配子生殖与病理变化

用单个肠艾美耳球虫Eimeria intestimalis Cheissin 1984卵囊感染无球虫兔,获得纯种进行研究。1.肠艾美耳球虫的配子生殖阶段寄生于空肠和回肠,此时宿主组织有较严重病变。12指肠、结肠和盲肠未见虫体,但在感染后264小时见盲肠的个别绒毛内有1～3个配子体,可能属偶然现象。2.感染后180小时发现极少数早期配子体,感染后192小时出现少量配子体寄生在空肠和回肠的绒毛和腺上皮细胞内,感染后216至264小时,绒毛上皮和腺上皮细胞内多为配子体、合子和卵囊所取代。感染后216小时出现极少量卵囊,264小时则见有大量卵囊。3.感染开始时(感染后61～73小时),回肠、空肠绒毛上皮正常;腺上皮细胞出现少量滋养体和裂殖体。96至192小时后,肠绒毛上皮和腺上皮受侵害程度渐趋严重,肠绒毛变矮,绒毛上皮及腺上皮细胞肿大变空,细胞核消失。许多腺泡塌陷。感染后216～264小时,肠绒毛受侵害最为严重,空肠和回肠绒毛萎缩或消失,变为一层矮柱或立方形上皮细胞或全无上皮细胞覆盖的绒毛。固有层均质红染,或颗粒状。肠腺塌陷,数量减少,大小不一。腺腔内见有配子体、合子或卵囊残留,部分腺泡上皮细胞再生,细胞核增生成堆。12指肠、盲肠和结肠正常。     

仔猪传染性胃肠炎的PCR检测及组织病理学观察

对江苏某养殖场送检的3只病死腹泻仔猪进行临床观察、病理组织学观察,并结合病原学检测结果对患猪腹泻原因进行了分析。结果显示,剖检病死仔猪病变主要在胃和小肠,胃内有凝乳块,胃底部黏膜充血,小肠臌气,肠壁变薄。组织病理学变化主要为12指肠卡他性炎症,空肠肠绒毛显著萎缩,肠绒毛上皮变为扁平上皮且发生空泡变性,肠黏膜层局部坏死脱落,黏膜下层白细胞浸润;胃黏膜上皮变性、坏死脱落,固有层及黏膜下层充血及大量淋巴细胞浸润,局部胃黏膜层完全坏死,甚至形成溃疡;用针对K88、K99、987P、F41的单抗对分离到的大肠杆菌通过玻板凝集试验进行检测,结果显示为阴性。PCR检测结果为猪传染性胃肠炎病毒阳性。     

Pathology of Mycoplasma agalactiae induced granular vulvovaginitis (GVV) in goats.

Granular vulvovaginitis (GVV) was experimentally produced in female kids by topical application of M. agalactiae on the scarified vulvar mucosa. Grossly visible GVV lesions were seen in 25 out of 30 infected kids, yet all were positive for microscopic lesions. Microscope lesions that appeared by 7 days post infection (DPI) were comprised of stromal oedema, lymphocytic infiltration into the lamina propria and perivascular accumulation of a few lymphocytes. The lesions observed between 28 and 49 DPI were comparable to those of spontaneous cases (severe). The changes seen in kids euthanized between 56 to 70 DPI were suggestive of the chronic stage of the disease. M. agalactiae was reisolated from all the infected kids from 7 to 70 days after inoculation. The pathology and pathogenesis of this condition have been described and discussed.     

Effects of contact dermatitis on hepatic gene expression in broilers

1.?Severe foot and hock dermatitis in broiler chickens can reduce growth rate and increase susceptibility to bacterial infection, affecting both profitability and welfare. However, little is known about the underlying physiological changes associated with foot and hock lesions.

2.?This study compared global hepatic gene expression in control birds and those with ammonia-induced foot and hock lesions using Agilent 44?K chicken oligonucleotide microarrays (8 birds per group).

3.?In total, 417 genes were differentially expressed of which 174 could be mapped onto the genome. Genes associated with energy metabolism, thyroid hormone activity and cellular control were affected, while there was also evidence of an up-regulation of genes linked to a pro-inflammatory response.

4.?It is conceivable that pain is the underlying cause for the observed changes in energy metabolism genes.

5.?Changes in hepatic gene expression provide new information on how a chicken's physiological mechanisms alter to cope with foot and hock lesions. The findings support other data indicating that birds with increased severity of lesions are likely to be in pain and that growth will be compromised. Reduction of the incidence of dermatitis by improved husbandry should therefore benefit both welfare and commercial performance.     

急性冰水应激对犬血清甲状腺激素、NO及Na、K、Cl离子含量的影响

通过测定急性冰水应激时犬血清甲状腺激素、NO及Na、K、Cl离子含量的变化,来评价急性冰水应激对犬体内能量代谢、氧化应激状态及电解质平衡的影响。试验选取8只成年杂种犬,保定躯干浸于冰水混合物中(0~4)℃,使其进行冰水浴30 min。分别于处理前0.5 h(-0.5 h)及处理后0、0.5、1、3、7 h进行桡静脉采血2 mL,分离血清后测定其甲状腺激素(T3、T4)、一氧化氮(NO)及Na^+、K^+、Cl^-的含量。结果表明:与-0.5 h(处理前)相比,处理后各时间点犬血清T3含量无显著变化(P>0.05),与-0.5 h及0、3、7 h相比,血清T4含量在0.5 h时显著降低(P<0.05);血清NO含量在处理后各时间点均显著高于处理前0.5 h(P<0.05),且1、3、7 h显著高于0、0.5 h(P<0.05);与-0.5 h相比,处理后3 h血清Na^+含量显著升高(P<0.05),血清K^+含量处理后0 h显著高于1、3、7 h(P<0.05),血清Cl^-含量处理前后差异不显著(P>0.05)。研究表明,急性短期冰水应激会扰乱机体的能量代谢状态、降低T4含量,同时造成氧化应激损伤、使NO含量大量升高;引起血清Na、K离子平衡紊乱、含量升高,提示临床上人或动物发生冰水应激时应及时纠正机体能量代谢、氧化还原平衡和电解质的紊乱。     

Studies on effects of lactose on experimental Trypanosoma vivax infection in Zebu cattle. 1. Plasma kinetics of intravenously administered lactose at onset of infection and pathology

Lactose in normal saline was administered intravenously to a group of Zebu cattle infected with Trypanosoma vivax to determine the blood plasma kinetics at onset of an experimental infection and its ability to protect tissues against damage as part of preliminary studies to determine its suitability for use in the treatment of trypanosomosis. Significantly (P < 0.01) higher lactose concentrations were observed in the T. vivax-infected bulls at 30 min and 1 h (P < 0.05) post-infection (p.i.) and by 4 h p.i. the plasma lactose remained above the level prior to infusion, after which it fell slightly below the pre-infusion level in the uninfected group. Calculated pharmacokinetic parameters revealed delayed excretion of lactose in the T. vivax-infected group soon after infection. The total body clearance (Cl(B)) was significantly (P < 0.05) reduced. The biological half-life (t1/2), elimination rate constant (k(el)) and apparent volume of distribution (V(d)) were relatively decreased (P > 0.05) as a result of the T. vivax infection. Retention of lactose in the plasma was attributed to decreased plasma clearance. It is suggested that the presence of trypanosomes in circulation rather than organic lesions could have been responsible for the delay observed in the excretion of lactose. At 12 weeks p.i., when the experiment was terminated, the group infected and given lactose infusion (despite higher parasitaemia) had no gross or histopathological lesions in the brain, spleen, lymph nodes, heart, kidneys, liver and testes. However, the group infected but not infused with lactose were emaciated, had pale mucosae, watery blood, general muscular atrophy, serous atrophy of coronary fat and other adipose tissue, hepatomegaly, splenomegaly, swollen and oedematous lymph nodes, all of which are suggestive of trypanosomosis. Histopathological lesions included narrowing of Bowman's space and hypercellularity of glomerular tufts in the kidneys with the mean glomerular tuft nuclear indices (GTNs) in the group significantly higher (P < 0.01) than the mean GTNs of the lactose-infused and control bulls. Degenerative changes occurred in the myocardium, spleen, testes and epididymides. The tesicular and epididymal lesions are indicative of male reproductive dysfunction.     

Phenotypic and functional modulation of bone marrow-derived dendritic cells by porcine reproductive and respiratory syndrome virus

It is well documented that there is a delay in the development of effective immunity to porcine reproductive and respiratory syndrome virus (PRRSV) in infected and vaccinated pigs. This suggests that PRRSV might possess some inherent properties to evade host defense mechanisms during the early stage of infection. Dendritic cells (DCs) play a crucial role in the activation and control of T-cells in response to viral antigens. In this study, we investigated the phenotypic and functional property changes of bone marrow-derived immature DCs (BM-imDCs) that take place after infection by PRRSV. Results showed that BM-imDCs were permissive to PRRSV infection, as productive replication took place in these cells. A down-regulated expression of MHC I molecules along with an up-regulated expression of CD80/86 is observed at 48 h following infection. Also at 48 h following PRRSV infection, a significant increase of IL-10 secretion by BM-imDCs was noticed. Results suggest that the inhibited expression of MHC I and the enhanced secretion of IL-10 by BM-imDCs after PRRSV infection might be among the strategies used by the virus to evade the host immune defenses.     

A comparison of the morphologic effects of Serpulina hyodysenteriae or its beta-hemolysin on the murine cecal mucosa.

Studies were carried out to compare the early morphologic changes in the cecal mucosa of mice either infected with Serpulina hyodysenteriae or exposed to the beta-hemolysin of S. hyodysenteriae. Sixty-five 12-24-week-old C3H/HeOuJ mice were infected with S. hyodysenteriae by gastric intubation. Two mice were necropsied every hour for 30 hours following infection. S. hyodysenteriae was isolated from the cecal contents of each mouse at all time points. Macroscopic lesions were first apparent at 14 hours postinfection (PI), and light microscopic lesions were first apparent at 10 hours PI, earlier than has been previously reported. Ultrastructural changes, first evident at 6 hours PI, included disarray and loss of microvilli and terminal web, with dilatation of intercellular spaces. Luminal bacteria were translocated through epithelial cells to the lamina propria, where capillaries exhibited changes indicative of increased permeability. In another experiment, solutions containing between 2,500 and 25,000 hemolytic units of purified S. hyodysenteriae hemolysin were placed within the lumen of surgically closed murine ceca (n = 10); ceca were collected for examination 3 hours following treatment. Ultrastructural changes consisted of loss of microvilli and terminal web and marked vacuolation and exfoliation of epithelial cells. Significant numbers of necrotic and apoptotic epithelial cells were present, and epithelial cells internalized moderate numbers of bacteria. The hemolysin of S. hyodysenteriae induces some of the same early ultrastructural changes in the cecal epithelium of mice as occur following infection with S. hyodysenteriae. Based on the observed bacterial translocation, luminal bacteria also appear to play a unique role in lesion development in this model.     

Wesselsbron disease: virological and serological studies in experimentally infected sheep and goats

Adult sheep and goats and new-born lambs and kids were experimentally infected with a Wesselsbron disease virus. The viraemia in lambs commenced approximately 27 h after infection and lasted on the average for 50 h. A febrile reaction, which was mostly biphasic, commenced several hours after the viraemia and outlasted it by 50 h. The viraemia in adult animals began about 50 h after infection and lasted for 30 h. The fever usually commenced several hours after the viraemia and, as in 3 cases out of 4 in lambs, it outlasted the viraemia by at least 30 h. The virus could be reisolated in mice from every tissue examined in lambs, although it has previously been shown that pathological lesions are restricted to the liver and lymphatic tissues.     

Effects of Dietary Crude Protein Levels on Growth Performance,Digestion and Metabolism,and Serum Biochemical Indexes of Super Merino Lamb

The experiment aimed to find out the effects of dietary crude protein levels on growth performance, digestion and metabolism and serum biochemical indexes of Super Merino lamb after weaning.According to the dietary crude protein level, 64 Super Merino weaned lambs were divided into four groups, which the crude protein levels were 13.25%(group Ⅰ), 14.33%(group Ⅱ), 15.53%(group Ⅲ) and 16.60%(group Ⅳ), respectively.The experiment lasted for 60 days, 30 days for the early stage and 30 days for the later stage;And on the 30th and 60th day, blood samples were collected from one head sheep chosen from each replication, and at the end of the feeding test, 3 lambs were randomly selected from each experiment group for a 15 days digestion and metabolism experiment.The results showed that ADFI and ADG in the early and total trial period were significant differences(P<0.05), ADFI and ADG of group Ⅲ were higher than others.The apparent digestibility of nutrients and ME/DE were not significantly changed(P>0.05).In the detection of serum biochemical indexes, there was no significant difference in the earlier stage(P>0.05);At the end of the test, PK and CK showed significant difference between groups(P<0.05).PK presented a rising trend as the protein level improved, CK of group Ⅰ was higher than other groups.In Super Merino lamb early weaning diet, 15.53% protein level in the diet could significantly improve ADG, the apparent digestibility of nutrients, metabolic energy digestibility.At the end of the test, PK and CK were affected by dietary crude protein level significantly.     

日粮粗蛋白质水平对苏博美利奴羊生长性能、消化代谢及血清生化指标的影响

试验旨在研究不同粗蛋白质水平日粮对断奶初期苏博美利奴羊生长性能、消化代谢及血清生化指标的影响。按照日粮粗蛋白质水平将64只苏博美利奴羊断奶羔羊随机分为4组,粗蛋白质水平分别为13.25%(Ⅰ组)、14.33%(Ⅱ组)、15.53%(Ⅲ组)、16.60%(Ⅳ组)。进行为期60 d的饲养试验,试验前期30 d,试验后期30 d。第30和60天称重后,在每个重复随机抽取1只羊进行血液样品采集。饲养试验结束后从每个试验组中随机选取3只苏博美利奴羊进行为期15 d的消化代谢试验。结果表明,4个试验组平均日增重和平均日采食量在试验前期和试验全期均存在显著差异(P<0.05),Ⅲ组的平均日增重和平均日采食量在整个试验期均高于其他3组。各组养分表观消化率及消化能代谢率均不存在显著差异(P>0.05)。在血清生化指标的检测中,试验前期各试验组不存在显著差异(P>0.05);试验后期丙酮酸激酶和肌酸激酶组间差异显著(P<0.05)。丙酮酸激酶随着日粮粗蛋白质水平的提高呈现出上升趋势,Ⅰ组肌酸激酶高于其他各组。在苏博美利奴羊断奶初期的日粮中,15.53%粗蛋白质水平的日粮配方使羔羊平均日增重显著提高,养分表观消化率、消化能代谢率均高于其他各组。到试验结束时,血清丙酮酸激酶和肌酸激酶受日粮粗蛋白质水平影响显著。