Preparation and Evaluation of Mixed Probiotics for Chicken Against Escherichia coli Infection

The purpose of this study was to explore the effects of probiotics on chickens' resistance to Escherichia coli infections,and to provide a basis for the development of microecological agents.Based on the Oxford Cup test and the bacterial adhesion inhibition test,three kinds of probiotics and their equal proportion mixed bacterial liquid with good effect of inhibiting Escherichia coli in vitro were obtained initially:Lactobacillus plantarum ZN-3,Lactobacillus rhamnosus QC,Clostridium butyricum HYCB and mixed bacteria preparation X.The 7-day-old SPF chicks were continuously orally fed with probiotics for 30 days and infected with Escherichia coli XT-13 once a day from the 26th to 30th day,and the survival rate and weight change were recorded.Through the same oral and infection protocols,the chicks were necropsied after infection with XT-13,and the results of necropsy and pathology were analyzed,and the amount of bacteria in the liver and intestines was detected by immunohistochemistry.In addition,in order to analyze the effect of oral administration of mixed probiotic preparations on cytokines in chickens infected with Escherichia coli,non-lethal doses of XT-13 were selected to infect chickens,and the levels of interleukin-10 (IL-10),interleukin-17 (IL-17) in serum and avian defensin-β1 (AvBD1) in the liver were measured on the 4th,8th and 14th days after infection.At the same time,the bactericidal ability of the serum was tested on the 14th day after infection.Finally,the broad-spectrum protection ability of probiotics to O78 serotype Escherichia coli AV006 infected chickens was evaluated.The results showed that the antibacterial effect of the supernatant of each probiotic fermentation broth was obvious,and the mixing of probiotics could reduce the adhesion rate of XT-13 to DF-1 cells (P<0.05).The weight gain effect of mixed probiotics was better than that of single probiotics,which had a good protective effect on chickens infected with XT-13.The survival rate was 87.50%.The mixed probiotics significantly reduced the load of XT-13 in liver and large intestine,alleviated the pathological damage,and regulated the levels of IL-10 and IL-17 in serum and the levels of AvBD1 in the liver,while improving the bactericidal ability of the serum.In addition,the broad-spectrum protection test showed that the mixed probiotics reduced the mortality of chickens infected with O78 serotype Escherichia coli.Therefore,the mixed preparation of Lactobacillus plantarum ZN-3,Lactobacillus rhamnosus QC and Clostridium butyricum HYCB could promote chick weight gain,reduce bacterial load,reduce tissue lesions,regulate the host's immune response,and had a good prevention effect on avian colibacillosis,which had a great potential to develop into a probiotic preparation against avian colibacillosis.     

金黄地鼠Dpl基因克隆及其组织特异性表达的研究

本文成功克隆了金黄地鼠Dpl(PrP-like protein doppel,Doppel)基因,并采用实时荧光定量PCR法对其组织特异性表达进行了研究.根据已发表家鼠Dpl基因序列设计引物,采用PCR直接扩增金黄地鼠(Ham.ster)的Dpl基因CDs区,序列测定和分析表明金黄地鼠的Dpl基因CDs区全长537 bp,编码178个氨基酸的前体蛋白,不存在基因多态性.经基因序列对比分析,金黄地鼠与其他10种属哺乳动物Dpl基因有较高同源性,均为70.8%以上,且与鼠科Dpl序列的同源性最高(86%).实时定量PCR结果表明,在所检测组织中,Dpl m.RNA在睾丸表达量最高,其次为脾脏、心脏、骨髓和脑,其在肝脏、肺脏、肾脏和肌肉中的表达低于检测水平;成年动物与未成年动物相比,在睾丸组织的表达量,成年鼠显著高于未成年鼠;在成年鼠脑组织检测不到Dpl m.RNA 的表达.本研究对金黄地鼠Dpl基因序列进行分析测定,并对其在不同组织的生理表达进行了定量,以期为其功能的进一步研究提供基础数据.     

木塑复合材料加工技术及经济效益分析

木塑复合材料的研制和广泛应用，有助于减缓塑料废弃物和农业废弃物焚烧给环境带来的污染。为此，概述了木塑复合材料目前国内外研究现状，并对其加工工艺进行了描述，然后根据一个小型公司，进行了经济效益分析，得出结论：该项目投资小，见效快，投资回收期短，抗风险能力强，是一项切实可行的好项目。     

基于脉冲多重化的数字SPWM技术

为有效降低SPWM逆变波形的谐波含量,提出了一种新颖的脉冲多重化数字SPWM逆变控制技术.与SPWM电平多重化技术不同,脉冲多重化是在每个逆变PWM周期,将SPWM脉冲在时间轴上进行的时间多重化.算法直接以数字正弦序列为基础,省去了以往SPWM脉宽计算的大量复杂过程,有效降低了系统的脉宽计算量.对脉冲多重化SPWM逆变波形频谱进行了理论计算与分析,证明了该技术可以在不增加系统现有开关频率的基础上,进一步降低SPWM逆变波形的谐波含量.最后,给出了该算法的工程实现方法,通过构建实验平台,对该算法进行了实验验证.实验结果证明了该技术的有效性,文中理论分析结果与实际情况完全一致.     

采用拦沙坝防护的浅基桥梁墩台局部冲刷研究

采用水力模型试验的方法,针对典型工程,对桥墩周围河床的局部冲刷及拦沙坝的防护作用进行研究.初步研究表明,在桥墩下游修建拦沙坝作为遏制浅基桥梁附近河段溯源冲刷的工程防护形式是可行的,拦沙坝减缓桥墩附近局部冲刷的作用非常明显.通过研究提出的采用拦沙坝防护的桥墩局部冲刷公式为浅基桥梁工程防护设计提供了参考依据.     

以“三个有利于”为指南实践正邦人一心为公的行为

对于一个组织来说没有什么比得上团结更为重要,任何管理模式最终目的就是为了凝聚人心,充分发挥人的创造力和主观能动性.     

樟树物候观测

在雷州半岛建立固定样地进行对樟树物候观测,研究樟树的生物学特性及物候规律,为樟树人工林栽培提供科学依据和技术支撑。     

三种紫外线辐照对黑腹果蝇蛹的影响

分别利用三种紫外灯(UVA、UVB、UVC)辐照黑腹果蝇蛹,研究辐照对黑腹果蝇的羽化率、性比、飞出率、死蛹率、成虫干重、蛹重以及F1羽化率、F1性比、F1死蛹率、F1成虫干重的影响.结果 表明:辐照后黑腹果蝇羽化率均显著降低,其中UVB辐照6h后的黑腹果蝇蛹羽化率最低,为10.00％;经过UVA辐照9h组的性比平均值为...     

不同饲喂方式对南方奶牛产奶性能、养分消化和代谢的影响

研究了具有南方奶牛日粮类型特征的相同精粗比日粮的不同饲喂方式对奶牛的采食行为、产奶性能、全肠道养分表观消化率和血清代谢产物的影响.选用体重相近的12头荷斯坦奶牛,采用单因子设计,根据产奶量、胎次及泌乳天数随机分为2组(n=6),分别为精粗分饲组(SI)和全混合日粮组(TMR),精饲料:粗饲料均为50:50.试验结果表明:奶牛采食量无差异,在相同精粗比日粮下,TMR饲养技术极显著减少了奶牛的采食时间(P<0.01),显著增加了反刍时间(P<0.05),TMR组奶牛的乳脂率、4%标准奶产量、乳脂产量、乳糖产量和乳固形物产量分别比SI组显著提高11.20%、11.60%、17.50%、13.21%和9.86%(P<0.05),但对奶牛咀嚼行为、全肠道养分表观消化率和血清代谢产物影响不显著(P>0.05).在南方奶牛典型日粮采用TMR饲养技术时,与精粗分饲相比,可提高奶牛的产奶性能,但对奶牛的采食量、咀嚼行为、全肠道养分表观消化率和血清代谢产物没有显著影响.     

抗梅岭霉素和阿维菌素二斑叶螨种群生命力和繁殖力的研究

采用营养液培养的棉苗饲养二斑叶螨Tetranychus urticae Koch,用梅岭霉素、阿维菌素对其逐代进行抗性选育,至第9代,测定了两个抗性种群的抗性水平、生命力和繁殖力。结果表明:梅岭霉素抗性种群的抗性达7.9倍,其雌成螨寿命、产卵量、卵的孵化率和后代若螨成活率分别比对照增加54.08%、39.93%、6.57%和-15.44%。阿维菌素抗性种群的抗性达5.8倍,其雌成螨寿命、产卵量、卵的孵化率和后代若螨成活率分别比对照增加15.88%、10.87%、5.86%和-9.32%。由此发现梅岭霉素和阿维菌素对二斑叶螨的生长发育和繁殖有一定有利作用,抗性风险性较大,应引起重视。