鸭源多杀性巴氏杆菌在人工感染雏鸭体内的动态研究

为探索多杀性巴氏杆菌在雏鸭体内的动态病理变化,用小鼠复壮鸭源多杀性巴氏杆菌,经测定其滴鼻途径的LD50=1×10-4.5/0.2 mL,口服途径的LD50=1×10-2.375/0.2mL.用100 LD50剂量,以口服、滴鼻途径分别感染雏鸭,于感染后6 h、12 h、18 h和24 h取心、肝、肺、肾及胸腺进行组织活菌计数.口服和滴鼻感染后12 h,从胸腺、肝、心、肺检测到生长繁殖的病原菌,18 h从口服感染组的肾脏检出目标菌,24 h从滴鼻组的肾脏检出目标菌.口服感染12 h,胸腺中菌数最高,达5.33×103 CFU/g,依次是肝、肺、心、肾.滴鼻感染12h,肺中菌数最高,达5.00×103 CFU/g,依次是胸腺、肝、心、肾.24 h均以胸腺菌数最高.表明检测体内鸭巴氏杆菌抗原或分离病原菌,首选器官是胸腺和肺,其次是肝、心.同时取心、肝、肺、肾、脾、胸腺、法氏囊、腺胃和十二指肠制作病理切片.消化道途径感染出现病变的最早时间是侵入后6 h,呼吸道途径感染出现病变的时间小于6 h.口服途径感染雏鸭后6 h,各器官都表现以充血为主要特征的轻微病理变化,6 h～12 h表现以细胞肿胀、开始细胞变性为特征的病理变化.12 h～18 h表现细胞变性加剧,开始核浓缩、核碎裂为特征的病理变化.18 h～24 h表现核浓缩、核碎裂加剧,细胞溶解的细菌损伤病理,以及淋巴细胞浸润、免疫器官网状内皮细胞增生相伴的免疫损伤.滴鼻途径的病理变化与口服途径相似,但病理进程有所提前.鸭多杀性巴氏杆菌对胸腺、脾、法氏囊等免疫器官造成病理损伤,以胸腺和脾脏的损伤较为严重.     

肉鸡腹水综合征病理诊断及治疗

肉鸡腹水综合征(Ascites syndron in droiers)是一种由多种致病因子共同导致的以在心肥大扩张和腹腔内积聚浆液性淡黄包流体为特征,有着明显的腹水、右心扩张、肺充血、水肿以及肝脏器官病理性扣伤的为特征的一种非传染性疾病。本试验对因腹水病而死亡的肉鸡的心、肝、肺、脾、胃、肠、肾、大脑、胸腺、法氏囊等组织,用10%福尔马林固定,常规石蜡切片,HE染色进行诊断。试验结果显示:因腹水病死亡的肉鸡的心、肝、肺、脾、胃、肠、肾、大脑、胸腺、法氏囊等组织均有不同程度的病变。     

维生素C溶液对热应激蛋仔鸡血清及组织变化的影响

为了探究维生素C溶液对热应激蛋仔鸡血清氧化指标及肝、肾组织变化的影响。本研究选择150只30日龄伊莎褐蛋仔鸡随机分为热应激组、维生素C原粉+热应激组和维生素C溶液+热应激组,在热应激前进行为期7 d的给药期,再分别进行0 h、1 h、3 h、5 h和10 h热应激后,立即采集受试鸡的血及肝、肾组织。通过对血清中维生素C、丙二醛(MDA)、超氧化物歧化酶(SOD)水平的检测和肝肾组织病理学的检查,评价维生素C溶液对缓解受试鸡的肝肾组织细胞热应激损伤的保护作用。在热应激条件下,添加50μg/mL维生素C可以提高血清中维生素C含量,降低血清中MDA水平,减轻热应激导致的肝、肾组织细胞颗粒变性、空泡变性、核浓缩等损伤。维生素C溶液可能通过抗氧化能力而缓解热应激导致的肝、肾组织细胞损伤。     

热应激对肉鸡血液白细胞亚型比例变化的影响

本实验的目的是研究热应激对肉鸡血液白细胞亚型组分和比例变化的影响.实验采用60只40日龄AA肉鸡,在暴露于39±1℃的热应激环境持续2.5h后,肉鸡直肠温度及异嗜性细胞和嗜碱性细胞所占白细胞的比例皆有所升高.异嗜性细胞与淋巴细胞的比例(H/L)亦从0.23升至0.42.高温环境的应激还导致了单核细胞与淋巴细胞组分比例的下降,而嗜碱性细胞却未发现显著性变化.结果显示:在足以使肉鸡体温升高的环境温度的应激下,可致使循环血液中的白细胞组成发生变化.     

海生素对AA肉鸡免疫器官发育的影响

研究了饲料中添加海生素对AA肉鸡免疫器官发育的影响。144只AA肉鸡,随机分为2组,分别在饲料中添加0、200 mg/kg海生素,试验期42 d,每周末每组取试验鸡6只,颈动脉放血致死。取胸腺、腔上囊、脾脏,Bou in液固定,制作石蜡切片,HE染色,显微观察并摄影。结果:7日龄和42日龄试验组的胸腺指数高于同日龄的对照组,差异极显著(P<0.01);7日龄试验组腔上囊的器官指数升高,差异显著(P<0.05);35日龄试验组脾脏的器官指数升高,差异显著(P<0.05)。1~6周龄试验组中,胸腺、腔上囊和脾脏的组织结构也有不同程度的变化。其中脾的组织结构变化比较明显,尤其是脾小体变化甚为明显。试验表明:添加海生素能部分增加肉鸡免疫器官指数,促进免疫器官发育。     

肌肽对肉鸡免疫器官发育及ND疫苗免疫效果的影响

研究L-肌肽对肉仔鸡免疫器官发育及新城疫疫苗免疫效果的影响。选用AA肉鸡苗400只,随机均分4组,每组2个重复,在饮水中分别添加0、20、40、60mg/L L-肌肽,每周末各组测定ND抗体效价,胸腺、脾和法氏囊指数。结果表明:肌肽40、60mg/L剂量组能够不同程度地促进免疫器官的发育,提高胸腺、脾和法氏囊指数;增加ND抗体滴度水平。     

高温运输应激诱导类PSE鸡肉的形成机理

快速增长和肌肉增生型肉鸡品种选育导致大量异质鸡胸肉的产生。其中,类PSE(Pale soft and exudative-like meat)肉由于颜色苍白、质软、渗出率高严重影响消费者购买欲望,且由于蛋白变性导致的加工特性差、出品率低等问题给肉类加工业造成巨大损失。宰前应激会刺激动物机体神经-内分泌系统,影响免疫系统和生理代谢功能,造成宰后初期肌肉生理生化失调,也会对肉品质产生影响。本文旨在综述高温运输诱导类PSE肉的发生机制,探讨高温运输应激对肉鸡应激反应、能量代谢、氧化还原状态、钙离子通道蛋白和热休克蛋白70的影响,以期为改善肉鸡福利和降低类PSE肉的发生提供理论指导。     

肉鸡运输应激与抗应激的观察研究

<正> 肉鸡运输应激是指在运输过程中,由于捕捉、断水、断食、挤压、离速气流、噪音、颠簸及过度疲劳等运输性应激,造成肉鸡减重,体温上升,甚至大批死亡等非特异性疾病。有的虽不死亡,但出现病残或肉质下降,对肉鸡生产造成重大经济损失,是目前迫     

热应激影响雏鸡胸腺组织发育的研究进展

胸腺是免疫系统重要的中枢淋巴器官,高温条件下胸腺组织会遭受不同程度的损伤,产生免疫抑制,影响免疫功能。论文从热应激对雏鸡胸腺组织、胸腺细胞、相关分子表达的影响进行综述,并阐述缓解热应激对胸腺组织及免疫系统损伤的预防措施,提出了今后研究应重视的问题。     

宰前运输对肉鸡应激及肌肉品质的影响

规模化养殖的肉鸡在进出养殖场、转群、集中屠宰前都需要运输,运输过程不可避免会发生应激。强烈应激严重影响肉鸡的生理和代谢功能,从而使肉品质下降,甚至导致疾病、死亡。本文综述了影响宰前运输应激的相关因素,运输应激对肉鸡理化指标、物质代谢以及肌肉品质的影响,讨论了热应激蛋白、腺苷酸活化蛋白酶与肌肉品质的相关性,为研究运输应激相关机理和指导肉鸡业生产实践提供理论依据。     

Effects of transport and lairage time on some blood constituents of Friesian-cross steers in Chile

The objective of this study was to determine the effect of two transport journeys (3 and 16 h) and four lairage times at the abattoir (3, 6, 12 and 24 h) on some stress indicators in steers to validate the current Chilean legislation of a minimum lairage period of 12 h for cattle arriving at abattoirs.The study was carried out twice, 80 steers in the winter and 80 in the summer of 1999. Forty steers were transported for 3 h and 40 for 16 h. At arrival in the slaughterhouse, the 40 transported steers were randomly divided in four lairage groups. Blood samples were collected before loading at arrival at the slaughterhouse and at slaughter during exsanguination.Mixed models were used to determine the associations between the stress indicators and the independent variables while correcting for the repeated observations on animals. Lairage increased plasma cortisol and PCV values independent of the transport duration. Glucose concentrations in steers transported for 16 h further increased after 3 and 6 h of lairage but decreased after 12 and 24 h of lairage. In steers transported for 3 h, glucose concentrations only increased after 24 h of lairage. After 24 h of lairage, the steers transported for 16 h had increased βHB concentrations compared with those transported for 3 h. Plasma CK activity was increased in steers after transport but was not affected by lairage. The study shows that there is no beneficial effect on the welfare of the animals by a long lairage time at the abattoir.     

应激对猪生产性能、行为及血液理化指标影响的研究进展

应激条件下会影响猪的生产性能、行为及血液生理生化指标,对动物机体造成危害。因此,在畜牧生产实践中应尽一切努力防止应激特别是严重应激的发生,以免影响生产的有序进行,损害动物福利,降低经济效益。作者主要综述了断奶、冷、热、运输、屠宰等常见应激因素对猪的生产性能、行为及血液生理生化指标的影响。     

Characterisation of the pig acute phase protein response to road transport

The acute phase protein (APP) response was evaluated after prolonged transportation of pigs under commercial conditions. Elevated serum APP concentrations were observed in two groups of boars immediately after their arrival at a destination farm compared with within-animal control samples obtained one month later. The effect was more pronounced in the first group of pigs conveyed under average transport conditions (Transport 1, 24 h), although the second group was transported for a longer time period (Transport 2, 48 h) but in superior transport conditions. In a second trial, pigs were sampled before transport, on arrival at an abattoir (following 12 h transport), and at the slaughter-line (after 6 h lairage). Significant increases in major acute phase protein (Pig-MAP), haptoglobin, serum amyloid A, C-reactive protein, and a decrease in apolipoprotein A-I, were observed at slaughter. The results demonstrate that shipment of pigs by road can result in an APP response that is probably related to the stress of transport.     

内蒙古额尔古纳市畜禽屠宰现状分析及对策

内蒙古额尔古纳市畜禽屠宰经历了原始屠宰、松散集中屠宰和依法定点屠宰3个阶段,畜禽屠宰状况得到了极大改善。当前,额尔古纳市养殖业正由粗放式养殖模式向规模化、集约化养殖模式转变,但目前仍以粗放式散养为主。传统养殖模式也使得养殖户沿袭了自吃自宰、私屠滥宰的陋习,因此,私屠滥宰现象依然存在。简述内蒙古额尔古纳市的畜禽屠宰现状,分析畜禽屠宰过程中存在的主要问题,提出改进对策,以期为加强该市畜禽屠宰管理工作、提高畜禽产品质量安全提供有益参考。     

Effect of transport stress on physiological responses of male bovines

Forty-eight slaughter bulls were transported by road in groups of eight for approximately 30 min, 3 h and 6 h in two replicates. Animal welfare during the transport process was assessed. Loadings and unloadings were evaluated with a scoring method. Heart rates were monitored at the farm before loading and during all stages of transport. Blood samples were taken from all animals a week before transport and at sticking and analysed in terms of haematological values: hematocrit, haemoglobin, red and white blood cells (RBC and WBC), differential WBC counts and neutrophil:lymphocyte ratio. Glucose, creatine kinase, lactate and cortisol were also determined. To evaluate differences in meat quality, pH and water-holding capacity (WHC) were measured 24 h after slaughter. The loading and unloading scores were very low (low stress) but were associated with changes in heart rate, especially loading. Animals recovered their resting heart rate during the journey in medium and long transports. On the other hand, animals transported around 30 min maintained an elevated heart rate during the whole journey. All animals showed a stress response with significantly higher (p < 0.05) levels of erythrocyte series, N:L ratio, glucose and lactate. Animals transported for 3 and 6 hours had significantly (P<0.05) higher levels of cortisol than controls or 30 min transports, without differences between control and the shortest journey. Different transport times did not influence meat quality. Under good conditions, the transport had a slight effect on welfare, meat quality or physiological parameters related with stress.     

Slaughter value, meat quality, creatine kinase activity and cortisol levels in the blood serum of growing-finishing pigs slaughtered immediately after transport and after a rest period

The experimental materials comprised 44 hybrid [female (Polish Large White x Polish Landrace) x male Duroc] growing-finishing pigs. The animals were randomly divided into two groups: 24 pigs were slaughtered immediately after transport and 20 pigs were slaughtered after a 24-hour rest period in the lairage. The meat content of pork carcasses, carcass dressing percentage, the proximate chemical composition, physicochemical and sensory properties of meat and shear force values were determined. Serum creatine kinase activity and cortisol levels were determined in blood samples collected before transport and during carcass bleeding. Pigs slaughtered immediately after transport, compared with those slaughtered after a 24-hour rest period, were characterized by a higher meat content of the carcass and a higher carcass dressing percentage. Pre-slaughter handling had no effect on pork quality. The incidence of normal-quality meat, partially PSE (pale, soft, exudative) meat and PSE meat was similar in both groups. Chemical analysis showed that the content of dry matter, total protein, fat and minerals in meat was comparable in both groups. As regards the functional properties of the pork, samples from the carcasses of pigs that had rested before slaughter had a higher contribution of the red color component. Meat from pigs slaughtered immediately after transport had more desirable sensory properties. Pre-slaughter resting had a significant effect on those analyzed physiological parameters which were found to be good indicators of pre-slaughter stress. Serum creatine kinase activity and cortisol levels were higher in blood samples collected after transport (during carcass bleeding) than in samples collected before transport, pointing to a strong stress response of animals to pre-slaughter treatment. The decrease in serum cortisol levels in blood samples collected during bleeding from the carcasses of pigs slaughtered after a 24-hour rest period, compared with samples collected from animals slaughtered immediately after transport, suggests that rest before slaughter alleviated stress induced by pre-slaughter handling operations.     

Effects of transport stress on concentrations of cortisol, corticosteroid-binding globulin and glucocorticoid receptors in pigs with different halothane genotypes

Effects of stress on concentrations of cortisol and corticosteroid-binding globulin (CBG) in blood plasma and on glucocorticoid receptor concentrations in muscle cytosol were studied in pigs representing three Halothane (Hal) genotypes (NN, Nn, nn). At 12 wk of age, animals were divided into four groups: pigs subjected to transport (5 h in a truck), pigs treated with amperozide prior to transport, pigs not transported but treated with amperozide and pigs neither transported nor given amperozide. Animals were slaughtered the week they reached 100 kg live weight (3 mo later). The Hal gene showed no major influence on the variables studied except for cortisol concentrations (P = .06) measured directly after transport at 12 wk of age (NN = 66.8 nM, Nn = 61.4 nM, nn = 69.4 nM). However, the response in each Hal genotype differed, depending on whether or not the pigs had been exposed to transport. Two weeks after transport, NN pigs developed higher cortisol concentrations than untransported animals, whereas the response was reversed in nn animals; Nn pigs showed no difference in this regard. At slaughter, the effect of transport (12 wk of age) on cortisol and CBG was still apparent. In NN pigs cortisol and CBG concentrations were elevated (P less than or equal to .05, P = .08, respectively), whereas concentrations tended to be lower in nn pigs (P = .17, P = .07, respectively) when compared with untransported pigs. Transported pigs had lower receptor concentrations at slaughter (P less than or equal to .01) than untransported pigs. However, pigs given amperozide in connection with transport had a receptor concentration comparable to that in untransported pigs. Our study shows conclusively that transport stress had long-term effects on cortisol, CBG and glucocorticoid receptor concentrations. In addition, amperozide had long-term effects on cortisol and receptor concentrations.     

Impact of postovulatory food deprivation on the ova transport, hormonal profiles and metabolic changes in sows.

The effect of food deprivation on ova transport, hormonal profiles and metabolic changes was studied in 20 crossbred multiparous sows during their second oestrus after weaning. To determine the time of ovulation, transrectal ultrasonographic examination was performed. The sows were divided into 2 groups, one control group (C-group), which was fed according to Swedish standards, and one experimental group (E-group). The E-group sows were deprived of food from the first morning meal after ovulation until slaughter. Blood samples were collected every second hour from about 12 h before expected ovulation in the second oestrus after weaning until slaughter and were analysed for progesterone, prostaglandin F2 alpha-metabolite, insulin, glucose, free fatty acids and triglycerides. All sows were slaughtered approximately 48 h after ovulation and the genital tract was recovered. The isthmic part of the oviduct was divided into 3 equally long segments and flushed separately with phosphate buffered saline (PBS). Uterine horns were also flushed with PBS. A significantly greater number of ova were found in the first and second part of the isthmus in the E-group (p = 0.05) while in the C-group most of the ova were found in the third part of the isthmus or the uterus (p = 0.01). The level of prostaglandin F2 alpha-metabolite was significantly higher in the E-group compared with the C-group. The concentration of progesterone increased in both groups after ovulation but there were no significant differences between the groups. The other blood parameters showed that the food-deprived sows were in a catabolic state. The 48 h period of fasting results, directly or indirectly in an delayed ova transport, which may be due to a delayed relaxation in the smooth circular muscle layer of the isthmus.     

Comparison of different control strategies for foot-and-mouth disease: a study of the epidemics in Canada in 1951/52, Hampshire in 1967 and Northumberland in 1966

The measures used to control the epidemics of foot-and-mouth disease in Canada in 1951/52 (29 outbreaks) were compared with those used in the epidemic in Hampshire in 1967 (29 outbreaks). In both epidemics the disease spread more from premises where the disease was reported late and the imposition of quarantine or restrictions on infected premises was delayed. In Hampshire, area restrictions were imposed, susceptible livestock on infected premises and on premises in direct contact were slaughtered, and contacts were traced. In Canada, the initial diagnosis was vesicular stomatitis, no area restrictions were imposed, no tracing was carried out and the animals on infected premises were allowed to recover. However, apart from the disease's spread through infected meat and by unknown or airborne routes, it did not spread from infected premises once quarantine was imposed, partly owing to the low population density of livestock in the area. The effects of the slaughter of infected premises and direct contacts in the Fareham area of Hampshire in 1967 and in the Chathill area of Northumberland in 1966 were compared with what might have happened if, in addition, culling on contiguous premises or culling on premises within 3 km or emergency vaccination had been put into effect. The slaughter of cattle, sheep, goats and pigs on premises within 3 km two days after confirmation of the first outbreak would have resulted in fewer outbreaks and a shorter period to complete slaughter, but more animals would have been slaughtered. In the Chathill area, the slaughter of sheep, goats and pigs only on premises within 3 km two days after confirmation of the first outbreak would not have resulted in fewer outbreaks and more animals would have been slaughtered. Fewer premises and animals would have been slaughtered by a contiguous cull than by a 3 km cull but more than by the slaughter of infected premises and direct contacts. Emergency vaccination within 3 km, providing protection at four days (but not to animals already infected before the development of immunity), would have resulted in the fewest animals being slaughtered and could have reduced the number of outbreaks in the Fareham area by one and in the Chathill area by two or three. All the procedures would have had a greater effect the sooner they were introduced. However, with many foci of infection, priorities for action would have had to have been established. Earlier tracing of the last outbreak in the Fareham area could have shortened the Hampshire epidemic. Surveillance of a farm identified as at risk through animal movements and by the use of an airborne-prediction model could have eliminated the source of further outbreaks in the Chathill area.     

Tissue distribution of marbofloxacin after 'systemic' administration into the isolated perfused bovine udder

Mammary glands taken at slaughter from healthy lactating cows were perfused in vitro with warmed and gassed Tyrode solution. Marbofloxacin was administered "systemically" via the perfusion fluid at concentrations similar to those measured in plasma following intravenous administration of 2mg/kg marbofloxacin. Samples from the perfusate were taken over a 24h period. Glandular tissue samples at different vertical distances from the teat up to the udder base were gathered from each of the four quarters after 3, 6, 12 and 24h. The marbofloxacin content of the tissue samples was analysed by high performance liquid chromatography with UV detection. The addition of marbofloxacin to the perfusion fluid produced median concentrations above the MIC90 (0.016microg/mL) against Escherichia coli at all glandular tissue sites measured after 3 and 6h with remarkable variations. Samples taken after 12 and 24h contained marbofloxacin in concentrations (median) of 0.22 (<0.05-0.32)microg/g and 0.13 (<0.05-0.16)microg/g. It is concluded that a systemic administration of marbofloxacin is well suited for the treatment of E. coli mastitis.