引进美国SPF杜洛克种猪生产性能测定

选用引入的SPF杜洛克种猪76头，经过近三年的饲养观察及生产性能测定，达到原产地美国杜洛克种猪的生产性能，保持了原种猪的优良特性。与本场饲喂的大约克种猪生产性能比较，结果表明生长速度与胴体瘦肉率明显优于大约克猪，可作优良的瘦肉型猪终端父本。     

传染性法氏囊病病毒变异E株感染鸡细胞凋亡的研究

研究了传染性法氏囊病病毒（IBDV）变异E株人工感染28日龄SPF雏鸡后鸡法氏囊淋巴细胞的凋亡情况。电镜观察和DNA电泳分析结果表明,IBDV感染后12～48h,雏鸡法氏囊淋巴细胞出现典型细胞凋亡的形态学特征和生化特征;经流式细胞计检测和荧光染色观察,统计学分析表明,IBDV感染后24～48h,雏鸡法氏囊淋巴细胞凋亡数量显著增加（P<0.05或P<0.01）。试验结果揭示IBDV变异E株人工感染可以诱导雏鸡法氏囊淋巴细胞凋亡。     

SPF胶合木植筋抗拔性能研究

采用“拉-拉”荷载模式研究SPF(云杉-松木-冷杉)胶合木植筋抗拔性能,探讨了边距、胶层厚度以及长径比等对胶合木植筋连接抗拔强度和破坏模式的影响.结果表明:边距对植筋连接抗拔强度有显著影响,胶层厚度对植筋抗拔强度有极显著影响,长径比是影响植筋连接抗拔强度的重要因子;植筋连接抗拔强度随长径比的增大而增大,当长径比达到一定值时植筋抗拔强度取决于植筋杆的屈服强度;胶合木开裂、植筋杆拔出和植筋杆屈服是试验中的3种主要破坏模式.     

SPF试验动物饲料辐照剂量的模糊优化

γ射线辐照SPF试验动物饲料的关键性技术是辐照剂量的优化和确定。通过辐照处理对SPF饲料的理化、微生物和感官指标影响的研究 ,提出辐照灭菌处理的模糊综合质量评价方法 ,进而实现对辐照剂量的模糊优化。     

Experimental Infection of Mycoplasma ovipneumoniae in SPF Chicken Embryos

In order to evaluate the SPF chicken embryos as a candidate of the experimental model of Mycoplasma ovipneumoniae (Mo) infection,the 7-day-old SPF chicken embryos were infected with different concentrations of Mo(10⁸,10⁹ and 10¹⁰ ccu/mL) by injection of vitelline fluid and allantoic cavity.The mortality and Mo detection rate (PCR detection and isolation) of infected chicken embryos were employed to evaluate the optimal inoculation route,dose and sampling site.Three different isolates of Mo were submitted to injection of chicken embryos for pathogenicity comparison.The results showed that the optimal inoculation route and dose were vitelline fluid injection with 0.2 mL (10⁹ ccu/mL) Mo per embryo and the sampling site for detection was also vitelline fluid.Three Mo isolates revealed good infectivity and lethality to the chicken embryo.The chicken embryos mortality caused by FL3 strain (45%) and MoGH3-3 (40%) were both higher than that by A3 strain (25%),but with no significance (P>0.05).The detection rate of Mo from the chicken embryos in FL3 group (100%) was higher than that of MoGH3-3 strain(85%) and that of A3 strain (90%),but with no significance(P>0.05).This experiment preliminarily proved that the SPF chicken embryos could be infected and partially killed by Mo,and the virulence of different strains of Mo to the chicken embryos was different.The results provided the data for further establishment of the chicken embryo infection model of Mo,which would benefit the research on Mo pathogenicity and vaccine development.     

鸭源NDV对SPF鸭免疫机能的影响

【目的】探讨鸭源新城疫病毒(NDV)对SPF鸭免疫机能的影响。【方法】选用120只已免疫H5N1禽流感油乳剂灭活疫苗的SPF鸭,随机分为静脉注射组、点眼滴鼻组和对照组,每组40只。攻毒(2个试验组接种鸭源NDV 0.2mL(含病毒106 ELD50),对照组点眼滴鼻等量生理盐水)后观测各组鸭的发病死亡情况,于感染后不同时间随机剖杀试验组和对照组鸭,采集脾脏、法氏囊,按常规方法制备石蜡切片,TUNEL法检测脾脏、法氏囊细胞凋亡情况,同时检测血液生化和血液常规指标,并测定鸭源NDV对SPF鸭外周血中淋巴细胞转化率和H5N1油乳剂灭活疫苗HI抗体效价的影响以及CD4+/CD8+的动态变化,分析不同处理组鸭源NDV对SPF鸭免疫机能的影响。【结果】攻毒后,试验组SPF鸭发病率为100%,死亡率为32.5%,并出现呼吸困难、肺脏出血、腺胃乳头出血等症状及剖检变化;血常规检测结果显示,鸭源NDV静脉注射组和点眼滴鼻组血液中红细胞总数、血红蛋白含量先降低后显著升高,血小板总数、白细胞总数降低且均与对照组差异显著(P<0.05)或极显著(P<0.01);血液生化检测结果显示,试验组鸭谷丙转氨酶、谷草转氨酶、乳酸脱氢酶、肌酸激酶、淀粉酶活性升高,总蛋白含量降低,与对照组相比差异显著(P<0.05)或极显著(P<0.01);静脉注射组和点眼滴鼻组的H5N1油乳剂灭活疫苗HI抗体效价比对照组低但差异不显著,淋巴细胞转化率与对照组相比降低且差异显著(P<0.05)或极显著(P<0.01);静脉注射组与点眼滴鼻组的CD4+/CD8+变化趋势基本一致,均为先升高后降至正常水平以下。TUNEL法检测脾脏、法氏囊均出现细胞凋亡,且凋亡率随着攻毒后时间的增加而升高。【结论】SPF鸭接种鸭源NDV后能引起免疫抑制。     

引入西藏高原的家兔血液生化参数的比较研究

对引入西藏高原多年的加利福尼亚兔和中国白兔的12项血清生化指标进行测定,并与SPF新西兰兔进行比较。结果显示：①3个品种公兔之间,加尼福利亚兔与中国白兔比较,AST、TP、ALB、GLO、A／G、GLU、CRE、LDH差异极显著（P〈0．01）,TG、BUN差异显著（P〈0．05）,其中TP、ALB、A／G、CRE、CHOL、LDH表现极强的公兔特征,而ALT、GLU母兔明显高于公兔;加利福尼亚兔与SPF新西兰兔比较。ALT、A／G、CRE、TG、BUN差异显著（P〈0．05）,AST、CHOL、LDH差异极显著（P〈0．01）;中国白兔与SPF新西兰兔比较,ALT、AST、TP、ALB、GLO、A／G、CRE、CHOL、TG差异极显著（P〈0．01）;②3个品种母兔之间,加利福尼亚兔与中国白兔比较,ALT、GLO、CRE、TG差异显著（P〈0．05）,AST、TP、BUN、LDH差异极显著（P〈0．01）,加利福尼亚兔与SPF新西兰兔比较,ALT、TP、ALB、GLO、A／G、BUN、CRE、LDH差异极显著（P〈0．01）,AST、TG差异显著（P〈0．05）;中国白兔与SPF新西兰兔比较,ALT、TP、ALB、GLO、A／G、CRE、CHOL、TG、LDH差异极显著（P〈0．01）,BUN、AST差异显著（P〈0．05）。     

Reduced mucosal injury of SPF chickens by mast cell stabilization after infection with very virulent infectious bursal disease virus

Recent studies here have demonstrated that increased mast cell populations and tryptase activity contribute to lesion formation in regions of immune organs in special-pathogen-free chickens after infection with very virulent infectious bursal disease virus (vvIBDV). Mast cells and their mediators have been implicated in acute inflammatory injury after vvIBDV infection, but their precise role in this process remains elusive. In this study, the role of mast cells in the vvIBDV infection process was examined using ketotifen, a mast cell membrane stabilizer. On days 1, 2, and 3 postinfection, the bursa of Fabricius (BFs) were collected to quantify mast cells, tryptase and histamine contents by cytochemistry, immunohistochemistry and fluorospectrophotometry analyses, respectively. The results showed that the mast cell populations, tryptase expression, and histamine released increased significantly in the BFs (p < 0.01) of infected birds compared to controls, and acute inflammatory responses were observed in the former. In contrast, in infected chickens pretreated with ketotifen, mast cells, tryptase, and histamine were markedly decreased (p < 0.01) and probably as a result, the BFs remitted significantly. The overall results suggest that mast cells are positively involved in BF injury induced by vvIBDV infection. Inhibition of mast cell degranulation and concurrent mediator release may represent a novel strategy to modulate this process. This study, thus, advances the understanding of the acute inflammatory injury mechanisms triggered by vvIBDV infection and the contribution of mast cell activity in this process.     

鸡瘟毒清对鸡新城疫病毒的抑制作用

采用中药制剂鸡瘟毒清(由金银花、黄芩、黄芪、黄连、丹皮等10余味中草药组成)对鸡新城疫病毒进行体内和体外抑制实验。体内抑毒实验选用21日龄艾拔益加肉鸡,随机分为5组,每组32只,直接攻毒,攻毒前7 d开始给药,直至35 d,测定治愈率;体外抑毒实验选用11日龄SPF鸡胚,随机分为3组,每组12枚,攻毒给药后感作30 min,继续孵化,测定保护率。结果显示,中药制剂鸡瘟毒清对鸡新城疫病毒有较好的抑制作用,其中体内抑毒实验高剂量组治愈率高达91%,体外抑毒实验保护率达66.7%。     

Influence of maternal immunity on vaccine efficacy and susceptibility of one day old chicks against Egyptian highly pathogenic avian influenza H5N1

In Egypt, continuous circulation of highly pathogenic avian influenza (HPAI) H5N1 viruses of clade 2.2.1 in vaccinated commercial poultry challenges strenuous control efforts. Here, vaccine-derived maternal AIV H5 specific immunity in one-day old chicks was investigated as a factor of vaccine failure in long-term blanket vaccination campaigns in broiler chickens. H5 seropositive one-day old chicks were derived from breeders repeatedly immunized with a commercial inactivated vaccine based on the Potsdam/H5N2 strain. When challenged using the antigenically related HPAIV strain Italy/98 (H5N2) clinical protection was achieved until at least 10 days post-hatch although virus replication was not fully suppressed. No protection at all was observed against the Egyptian HPAIV strain EGYvar/H5N1 representing a vaccine escape lineage. Other groups of chicks with maternal immunity were vaccinated once at 3 or 14 days of age using either the Potsdam/H5N2 vaccine or a vaccine based on EGYvar/H5N1. At day 35 of age these chicks were challenged with the Egyptian HPAIV strain EGYcls/H5N1 which co-circulates with EGYvar/H5N1 but does not represent an antigenic drift variant. The Potsdam/H5N2 vaccinated groups were not protected against EGYcls/H5N1 infection while, in contrast, the EGYvar/H5N1 vaccinated chicks withstand challenge with EGYvar/H5N1 infection. In addition, the results showed that maternal antibodies could interfere with the immune response when a homologous vaccine strain was used.