致病性耐药大肠杆菌的噬菌体裂解试验

临床分离的致病性大肠杆菌的耐药谱很广,常规抗生素的治疗效果较差,对18种抗生素的平均耐药率高达80%。而用从污水中分离得到的噬菌体,经纯化增殖提高效价后,用来进行裂解试验则取得了比较满意的效果,其中对H1、H2、B1、P等几种菌的裂解率在80%以上。     

CC-Dp对伊犁马驹麦草采食量和血清激素的影响

本试验旨在探讨日粮中添加CC-Dp对马驹麦草采食量和血清中摄食调控激素的影响。选取20匹17月龄健康无病、体况和采食量相近的伊犁马驹,采用单因素试验设计,随机分为4组,每组5匹,对照组饲喂基础日粮,试验Ⅰ、Ⅱ、Ⅲ组分别在基础日粮中添加500、1000、1500 mg/kg CC-Dp。预试期7 d,正试期30 d。结果表明,与对照组相比,试验Ⅱ组马驹麦草采食量在试验第1~15天显著提高(P<0.05),血清中胆囊收缩素(CCK)和γ-氨基丁酸(GABA)含量在试验进行1~15 d分别显著降低和升高(P<0.05);与对照组相比,试验Ⅲ组马驹麦草采食量在试验全期内显著提高(P<0.05),血清中CCK含量在试验进行1~15 d极显著降低(P<0.01)、16~30 d显著降低(P<0.05),血清中GABA含量在试验全期均显著提高(P<0.05);各组间血清中神经肽Y(NPY)、5-羟色胺(5-HT)、瘦素(LEP)含量差异均不显著(P>0.05)。综上所述,日粮中添加1500 mg/kg CC-Dp能显著提高伊犁马驹麦草采食量,显著降低血清中胆囊收缩素含量,显著升高血清中γ-氨基丁酸含量,推测其作用机制可能是通过降低动物体内胆囊收缩素水平以调控动物的采食,且与γ-氨基丁酸的调控途径有关。     

许昌地区鸡大肠杆菌分离鉴定和某些生物学特性研究

在许昌地区10个鸡群中,无菌采集临床上疑似大肠杆菌病的18只病死鸡的心、肝。经接种培养、细菌镜检、生化试验、动物试验,共分离出大肠杆菌15株,其中有13株能使雏鸡发病死亡,但各菌株之间毒力存在明显差异;药敏试验表明:多数大肠杆菌对环丙沙星、氧氟沙星、氯霉素、壮观霉素、庆大霉素敏感;经O因子血清试验发现,其中有10株为O78,1株为O54,1株为O5,1株暂未定型。     

Post-Natal Dynamic Changes in Circulating Follicle-Stimulating Hormone, Luteinizing Hormone,Immunoreactive Inhibin,Progesterone, Testosterone and Estradiol-17β in Thoroughbred Colts until 6 Months of Age

The aim of present study was to clarify the post-natal profile of follicle-stimulating hormone (FSH), luteinizing hormone (LH), immunoreactive (ir)-inhibin, progesterone, testosterone, and estradiol-17β, and their relationships in Thoroughbred colts. Six hundred and thirty-six colts were used for the study. Single plasma samples from each animal were harvested from the blood drawn through jugular venipuncture. The subjects were born with high amounts of progesterone, testosterone, and estradiol-17β, all of which dropped significantly and remained at lower levels till the end of 6 months. FSH decreased transiently after birth until day 12 and then gradually increased to peak at day 100 which then maintained in lesser levels towards the end of the studied period. LH was highest during birth which decreased until day 26 and then increased slowly to sub-birth levels up to day 90. Animals were born with high amounts of ir-inhibin. It dropped slowly and halved by day 20 and then decreased towards rest of the studied period. The increase in FSH is negatively correlated with the declining ir-inhibin levels. The early increase in FSH can be the indication of early post-natal maturation of the hypothalamic pituitary testicular axis that ultimately might be responsible for priming the testes for future development.     

Empirical Growth Curve Estimation Using Sigmoid Sub-functions that Adjust Seasonal Compensatory Growth for Male Body Weight of Thoroughbred Horses

Thoroughbred horses are seasonal mating animals, raised in northern regions or countries. Foals born yearly in spring generally show a typical seasonal compensatory growth pattern, in which their growth rate declines in the first winter and increases in the next spring. In this study, a new empirical adjustment approach is proposed to adjust for this compensatory growth when growth curve equations are estimated, by using 1,633 male body weights of Thoroughbreds as an illustrating example. Based on general Richards growth curve equation, a new growth curve equation was developed and fit to the weight-age data. The new growth curve equation had a sigmoid sub-function that can adjust the compensatory growth, combined with the Richards biological parameter responsible for the maturity of animals. The unknown parameters included in the equations were estimated by SAS NLMIXED procedure. The goodness of fit was examined by using Akaike’s Information Criterion (AIC). The AIC values decreased from 13,053 (general Richards equation) to 12,794 (the newly developed equation), indicating the better fit of the new equation to the weight-age data. The shape of the growth curve was improved during the period of compensatory growth. The proposed method is one of the useful approaches for adjusting seasonal compensatory growth in growth curve estimations for Thoroughbreds, and for their management during the compensatory period. Based on this approach, the optimal growth curve equations can be estimated also for female body weight of Thoroughbreds or other growth traits affected by seasonal compensatory growth.     

鸡大肠杆菌病多价蜂胶灭活疫苗研究(Ⅱ报)——疫苗免疫持续期、安全性、保存期试验

以鸡大肠杆菌常见致病性血清型O_1、O_2、O_(78)3个血清型菌株制备5批鸡大肠杆菌病多价蜂胶灭活疫苗,并对其进行免疫持续期、安全性及保存期试验。免疫试验效果表明,5批疫苗近期保护率87.5％～100％,6个月保护率75％～87.5％;成年产蛋鸡在产蛋前2周于始免疫,免疫后3个月和6个月抽样攻毒,3个月保护率100％,6个月保护率87.5％以上。安全性试验证明,14日龄肉鸡0.5ml,40日龄蛋鸡注射1ml/只无临床反应,2ml/只,3ml/只剂量组注射后2～4h,产生临床上一过性反应,不引起鸡死亡。该疫苗在10～20℃条件下保存6个月,4～8℃保存18个月,免疫保护效果80％以上,疫苗久置有沉淀,用时需要充分摇匀。