原花青素A-1体内外对猪与小鼠T淋巴细胞亚群的影响

为研究从碎米花杜鹃叶中分离得到的化合物原花青素A-1（Proanthocyanidin A-1，简称PAA-1）的免疫增强活性，初步从细胞水平上探讨其免疫增强机制。体外试验采用流式细胞术，检测PAA-1体外对小鼠脾淋巴细胞T细胞亚群CD4和CD8单阳性和双阳性T淋巴细胞亚群百分率及CD4+/CD8+比值；体内试验通过饲喂不同剂量的PAA-1后，检测试验猪外周血淋巴细胞CD4和CD8单阳性以及CD4+/CD8+比值。结果证明，体外试验中同阴性对照组相比，PAA-1能单独或协同Con A提升具CD4+、CD8+及CD4+CD8+表型的T淋巴细胞亚群百分率，提高CD4+/CD8+的比值；体内试验中饲喂中、高剂量的PAA-1的试验猪外周血中具有CD4+、CD8+表型的T淋巴细胞的百分率及CD4+/CD8+的比值均有显著提高。说明PAA-1可通过增加辅助性T淋巴细胞和细胞毒性T淋巴细胞数量、促进T淋巴细胞的成熟以及增加CD4+/CD8+的比值发挥增强细胞免疫的作用，为其进一步开发为新型免疫增强剂提供试验依据。     

新生仔猪的护理——以上海某规模猪场为例

我国养猪业发展迅速，整体水平在不断提高，但是与养殖业较为发达的国家相比仍有一些差距。以每年每头母猪断奶的仔猪数（PSY）为例，目前国外养猪发达国家PSY普遍已超30头，而我国却仍在25头左右，仍有较大的提升空间。仔猪护理工作在生猪生产过程中尤为重要，一旦护理措施不当就会造成仔猪死亡，从而降低PSY，直接影响到养猪企业的经济效益。规模猪场仔猪死亡的主要原因就是由于仔猪护理不当所引起的，仔猪护理问题一直是养猪业的一个难题。文内以2020年4—5月上海某规模猪场某栋产房新生仔猪（共477头，其中压死8头，瘦弱致死12头，腹泻致死亡的32头）为例，介绍规模猪场的仔猪护理及注意事项，以期为仔猪护理工作提供借鉴。     

仔猪腹泻的病因分析及综合防制

仔猪腹泻是引起仔猪死亡的重要原因之一。该病病因复杂,始终是困扰养猪业的一大难题。文章详细分析了引起仔猪腹泻的非传染性病因（环境、仔猪自身等）及传染性病因（细菌、病毒、寄生虫等）,提出了预防为主,加强饲养管理及配合药物治疗的综合防制方案,对减少仔猪腹泻,维护养猪业的健康发展具有一定的指导意义。     

低温对仔猪生产的影响及其机制

仔猪死亡是养猪生产面临的重大问题，由于初生仔猪要求的环境温度高达３４℃，仔猪在初生后受寒是导致其被压死、饿死、虚弱死及腹泻死亡的重要因素。综述了低温对仔猪体温、初乳吸收和腹泻发生三方面的影响及机理，并提出了防治建议。     

饲用酸化剂研究进展

酸化剂被视为在畜禽饲料中的能有效替代抗生素的产品之一,近几年有关酸化剂的抗菌作用和调节营养生理功能的研究又取得许多新进展.通过搜索PubMed、CAB、Agricola、国家科技文献图书中心(NSTL)、国家知识基础设施(CNKI)数据库、万方数据库、维普数据库及相应的期刊,对国内外在仔猪日粮中添加饲用酸化剂研究应用概况作了较为全面综述.以期为饲用酸化剂在肉猪生产上的应用提供参考.     

仔猪腹泻防治效果观察

对怀孕母猪注射疫苗、投服药物,使其所产仔猪获得被动免疫,与此同时,对仔猪投服预防性药物,达到预防仔猪腹泻的目的.通过实践,使仔猪腹泻的发病率由35.65%下降到16.79%,死亡率由10.8%下降到0.98%,取得了较好的防治效果.     

Genetic analyses of piglet survival and individual birth weight on first generation data of a selection experiment for piglet survival under outdoor conditions

Genetic parameters of piglet survival traits and birth weight were estimated on the first generation data of a selection experiment aimed at improving piglet survival using a multiple trait linear and threshold model. Data on 5293 piglets for survival at birth, at day one after birth and during the entire nursing period, as well as individual birth weight and litter size, were recorded in an outdoor production system. Genetic effects of piglet survival traits and birth weight were estimated based on threshold and Gaussian models, respectively, using a Bayesian approach. The statistical model included as fixed effects selection group, parity, gender, fostering, gestation length and month of farrowing and, alternatively, an adjustment for litter size. Direct genetic effects (i.e. the piglet's genetic potential) for piglet survival and birth weight were estimated separately, whereas maternal genetic and environmental effects could only be estimated for the given data structure in a combined litter effect. Posterior means of heritabilities for direct genetic effects of survival at birth, at first day after birth and the entire nursing period, as well as birth weight, were 0.08, 0.07, 0.08 and 0.20, respectively. Genetic correlations among survival traits were in the range of 0.29 to 0.40 and indicate that these traits were mainly attributable to different genetic effects. Genetic correlations between direct effects of survival traits and birth weight ranged between 0.18 and 0.23 and were reduced when weights of stillborn piglets were omitted in the analysis or the traits were adjusted for litter size. The magnitudes of direct genetic effects of survival traits are substantially higher than estimates in the literature, which may indicate that these traits have a higher genetic influence under outdoor conditions. The use of birth weight in the multiple trait estimation provided important information for the estimation of survival traits due to its favourable genetic correlations with survival, its high heritability and its high information content as a continuously measured trait.     

Effects of dietary supplementation of nucleotides from late gestation to lactation on the performance and oxidative stress status of sows and their offspring

Increased metabolic burdens in breeding sows, which are induced by elevated systemic oxidative stress, could increase the need for nucleotides to repair lymphocyte DNA damage; however, de novo synthesis of nucleotides may be insufficient to cover this increased need. This study investigated the effects of dietary nucleotides on milk composition, oxidative stress status, and the reproductive and lactational performance of sows. Forty multiparous sows were assigned to 2 dietary treatments (Control group, and 1 g/kg Nucleotides group) based on a randomized complete block design using their BW at 85 d of gestation as a block. Sows from 2 groups were fed a restricted diet during gestation and ad libitum during lactation. The experiment lasted from 85 d of gestation to 21 d of lactation. The reproductive performance of sows and the growth performance of suckling piglets were measured. Oxidative stress parameters and milk components were also analysed. Data were analyzed using contrasts in the MIXED procedure of SAS. Sows in the Nucleotides group consumed more feed during the first week (P < 0.01) and from 1 to 21 d (P < 0.05) of lactation than those in Control group. Correspondingly, the litter weight gain of piglets showed a tendency to increase from cross-fostering to 9 d (P = 0.09) and from cross-fostering to 20 d (P = 0.10) in the Nucleotides group relative to the Control group. Additionally, the Nucleotides group was higher (P < 0.01) than the Control group in the concentrations of uridine 5''monophosphate, guanosine 5''monophosphate, inosine 5''monophosphate, adenosine 5''monophosphate and total nucleotides in milk. Furthermore, the Nucleotides group was higher (P < 0.01) than the Control group in the serum levels of total antioxidant capacity (P < 0.01) for sows at 109 d of gestation and glutathione peroxidase for weaning piglets, but lower at the levels of thiobarbituric acid-reactive substances (P < 0.05) in serum of weaning piglets. This study indicated that maternal dietary nucleotides could promote piglet growth, probably due to the higher lactational feed intake and higher concentration of nucleotides in the milk of sows, and lower oxidative stress for both sows and piglets.     

仔猪猪瘟疫苗乳前免疫技术的应用研究

目前在对猪瘟的防治实践中，对猪瘟超前免疫后四窝抗体水平的变化以及保护效果存在争议。通过本厂的应用观察：以品种、日龄相同，胎次相近的杜长大四窝三元仔猪为检测对象，每窝随机抽取五头进行超前免疫实验，分别在20日龄，30日龄，40日龄，60日龄，静脉采血，利用IDEXX公司的猪瘟检测试剂盒进行猪瘟阻断率检测，结果表明进行猪瘟超前免疫后再在50日龄加强一次猪瘟疫苗免疫能很好的保护仔猪     

麦科隆对大肠杆菌攻毒仔猪保护率及治疗效果试验

选择断奶1～10d杜长大三元杂交仔猪90头,按随机区组设计分为3组,A组(麦科隆预防试验组)、B组(麦科隆治疗试验组)、C组(青霉素治疗对照组)各30头。通过20d试验,在用致病性大肠杆菌攻毒后,A组发病率为20.00%,比未进行保护的B,C两组的66.67%,70.00%分别下降了46.67和50.00个百分点,差异极显著(P<0.01)。治愈率A组为100%,比B,C两组的91.13%和90.05%分别提高8.87和9.95个百分点,差异显著(P<0.05)。B,C两组比较,差异显著(P<0.05)。死淘率A组为0,B,C两组分别为4.67%和10.53%,A组与B,C两组比较,差异极显著(P<0.01)。B,C两组相比,差异显著(P<0.05)。说明麦科隆微生物制剂对大肠杆菌具有良好的预防和治疗作用,是抗生素的有效替代品。