Development and characterization of a potential diagnostic monoclonal antibody against capsid protein VP1 of the chicken anemia virus

Chicken anemia virus (CAV) is an important viral pathogen that causes anemia and severe immunodeficiency syndrome in chickens worldwide. In this study, a potential diagnostic monoclonal antibody against the CAV VP1 protein was developed which can precisely recognize the CAV antigen for diagnostic and virus recovery purposes. The VP1 gene of CAV encoding the N-terminus-deleted VP1 protein, VP1Nd129, was cloned into an Escherichia (E.) coli expression vector. After isopropyl-β-D-thiogalactopyronoside induction, VP1Nd129 protein was shown to be successfully expressed in the E. coli. By performing an enzyme-linked immunoabsorbent assay using two coating antigens, purified VP1Nd129 and CAV-infected liver tissue lysate, E3 monoclonal antibody (mAb) was found to have higher reactivity against VP1 protein than the other positive clones according to the result of limiting dilution method from 64 clones. Using immunohistochemistry, the presence of the VP1-specific mAb, E3, was confirmed using CAV-infected liver and thymus tissues as positive-infected samples. Additionally, CAV particle purification was also performed using an immunoaffinity column containing E3 mAb. The monoclonal E3 mAb developed in this study will not only be very useful for detecting CAV infection and performing histopathology studies of infected chickens, but may also be used to purify CAV particles in the future.     

Evaluation of modified vaccinia virus Ankara expressing VP2 protein of infectious bursal disease virus as an immunogen in chickens

A recombinant modified vaccinia Ankara (MVA) virus expressing mature viral protein 2 (VP2) of the infectious bursal disease virus (IBDV) was constructed to develop MVA-based vaccines for poultry. We demonstrated that this recombinant virus was able to induce a specific immune response by observing the production of anti-IBDV-seroneutralizing antibodies in specific pathogen-free chickens. Besides, as the epitopes of VP2 responsible to induce IBDV-neutralizing antibodies are discontinuous, our results suggest that VP2 protein expressed from MVA-VP2 maintained the correct conformational structure. To our knowledge, this is the first report on the usefulness of MVA-based vectors for developing recombinant vaccines for poultry.     

Changes in collagen fiber content and hepatic stellate cell distribution in the liver of chick embryos and growing chickens

The content of collagen and the distribution of hepatic stellate cells (HSCs) were studied to elucidate the occurrence of sex‐dependent variations in the liver of developing embryos and growing chickens. Chick embryos from embryonic days (e) 12 to e20 and chicks at 1, 4 and 8 weeks were analyzed. Liver tissue was processed using NaOH maceration and freeze‐dried to obtain the collagen fiber specimens. HSCs were identified by double fluorescent immunohistochemistry for desmin and vimentin. There were no sex‐dependent variations in the percentage of collagen fiber per liver weight and HSC area during embryonic stages. However, the content of collagen fiber increased during embryonic development in both sexes. On the other hand, the area of HSCs significantly increased in growing males but did not show any change in females. Importantly, sex differences were observed in both collagen fiber content and HSC area in the liver at 8 weeks. These results indicate that the occurrence of collagen content variations takes place at 8 weeks in chicken liver, suggesting that a sex‐dependent hormone may play an important role on the collagen production of HSCs in the growing chicken liver.     

Impacts of acute imipramine treatment on plasma and brain amino acid metabolism in mice given graded levels of dietary chicken protein

Several studies have shown a relationship between depression and animal protein intake. To evaluate whether the difference of dietary chicken protein levels induces an antidepressant‐like effect and potentiates acute antidepressant effects, three levels of dietary chicken protein were used as the representative animal protein with imipramine used as the antidepressant. In addition, the effects of dietary chicken protein on brain metabolism were evaluated. Open field test (OFT) and forced swimming test (FST) were conducted on the 27th and 28th days, respectively. OFT and FST were not influenced by both imipramine and dietary protein levels. However, characteristic effects of imipramine treatment on brain monoamine metabolism were observed in the cerebral cortex and hypothalamus. In addition, dietary protein significantly increased taurine and L‐ornithine levels even though these amino acids were not contained in the diets. In conclusion, the metabolism of several amino acids in the plasma and brain were altered by dietary chicken protein.     

规模化养鸡场粉尘的检测

鸡舍内粉尘浓度过高,会危害饲养员的健康和家禽的生产力,还会对周围环境造成污染。了解鸡舍内粉尘浓度空间变化情况,有助于进一步分析粉尘释放和变化规律,为开发更有效的除尘方法,试验测定了规模化养鸡场一年四季鸡舍门口和鸡舍中央的粉尘含量。结果表明,鸡舍中央位点全尘春季与冬季、秋季与冬季差异显著(P<0.05),夏季与冬季差异极显著(P<0.01);呼吸性粉尘PM10夏季与秋季差异显著(P<0.05),春季与冬季、秋季与冬季差异极显著(P<0.01);四季呼吸性粉尘PM10鸡舍中央位点与鸡舍门口差异不显著(P>0.05);全尘TSP鸡舍中央位点与鸡舍门口差异也不显著(P>0.05)。     

北京油鸡杂交效果的研究

为培育优质北京油鸡配套系提供理论依据,试验采用北京油鸡纯系(Y系)与北京油鸡合成品系(G系)进行正反杂交,观测亲本及其杂交组合的体尺、外貌性状、生长性能、屠宰性能和肉质性状,并比较各性状的杂种优势。结果表明:Y系与G系的正反交组合不仅在生长性能、屠宰性能及相应的肉质性能上具有显著的杂种优势,而且杂交后代能够很好地保持北京油鸡的外貌特征;在正反交组合中,以Y系为父系、G系为母系的正交组合(YG)表现的更为优秀。说明北京油鸡在优质鸡育种和杂交利用上更适合做父系,以充分利用其优良的遗传品质。     

家禽精液冷冻保存技术研究进展

家鸡精液冷冻保护是物种资源保存最廉价的方法。本文从家鸡精液的稀释液、冷冻保护剂、冻精形式、平衡时间、冷冻速率、解冻速率、精液质量检测方法等几个方面,综述了国内外研究进展,并对目前家鸡精液冷冻技术应用存在的问题进行了分析,提出了初步研究思路。     

用HI和ELISA方法检测SPF鸡血清和蛋黄中ND抗体的比较

分别用血凝抑制试验（HI）和酶联免疫吸附试验（ELISA）检测42周和48周SPF鸡血清、以及同期SPF鸡蛋蛋黄中新城疫（ND）抗体。结果表明,两种方法检测的120份血清中均无ND抗体,呈阴性;120枚SPF鸡蛋蛋黄检测,ELISA方法检测结果全为阴性;HI方法检测结果25份阳性,差异较为明显。     

华北柴鸡生长规律的研究

选择健康华北柴鸡商品雏200只为试验材料,饲养期共16周,在初生和各周龄末空腹称重,计算各周绝对增重、相对增重。从研究结果看,华北柴鸡体重的绝对增重在8周龄最高,公鸡与母鸡虽然增重数值略有差异,但生长高峰出现的时间基本相同。     

罗曼肉鸡生长发育规律研究

对1～9周龄的罗曼肉鸡体重进行了测量,计算了绝对生长、相对生长指标,运用Logistic、Gom-pertz和von Bertalanffy三种非线性模型对其累积生长情况进行了拟合与分析。结果表明：罗曼肉鸡在4周龄前生长缓慢,4周龄后逐渐加快;Gompertz模型和von Bertalanffy模型均能很好地拟合罗曼肉鸡的生长曲线（R2分别为0.9989和0.9998）,尤其是von Bertalanffy模型效果更佳,此模型拟合的生长曲线拐点日龄为39.23d,拐点体重为1512.09g。