Prevalence and risk factors associated with intestinal parasites in pigs in Chongqing, China

From 2007 to 2009, the prevalence of intestinal parasites was investigated in intensive and extensive pig farms in Chongqing, China. A total of 2971 samples from both sexes and five age categories (breeding boars, breeding sows, fatteners, growers and weaners) were evaluated by standard methods for the presence of helminth ova and protozoan oocysts, cysts and/or trophozoites. Of the 2971 pigs sampled, 362(12.18%) were infected with Ascaris suum, 301(10.13%) with Trichuris suis, 301(10.13%) with Oesophagostomum spp., 491(16.53%) with Eimeria spp., 149(5.02%) with Isopora suis, 677(22.79%) with Balantidium coli and 196(6.60%) with Cryptosporidium spp. Growers had the highest infection rate while breeding boars had the lowest among the five age categories. B. coli was the most common protozoan in all pig age groups. Pigs infected with multiple parasites were common. Risk factors such as management methods, seasons, ages, etc. can influence the infection rate to a certain degree. This investigation provides relevant data about risk factors for pig farmers, thus allowing them to make more appropriate antiparasitic treatments according to farm conditions and local climate in Chongqing.     

Low-density lipoprotein-related receptor protein 1 (LRP-1) is not required for insulin-like growth factor binding protein 3 (IGFBP-3) to suppress L6 myogenic cell proliferation

Insulin-like growth factor binding protein-3 (IGFBP-3) suppresses proliferation of numerous cell types, including myogenic cells, via both insulin-like growth factor (IGF)-dependent and IGF-independent mechanisms; however, the mechanism of IGF-independent suppression of proliferation is not clearly defined. In nonmuscle cells, binding of IGFBP-3 to the low-density lipoprotein receptor-related protein-1 (LRP-1)/activated α(2)M receptor is reportedly required for IGFBP-3 to inhibit proliferation. These findings suggest that binding to this receptor also may be required for IGFBP-3 to suppress proliferation of cultured myogenic cells. To investigate the role of the LRP-1 receptor in suppression of myogenic cell proliferation by IGFBP-3, we have examined the effect of receptor-associated protein, an LRP-1 receptor antagonist, on recombinant porcine (rp)IGFBP-3 inhibition of L6 myogenic cell proliferation. Treatment with receptor-associated protein results in a 37% decrease (P < 0.05) in the ability of rpIGFBP-3 to inhibit L6-cell proliferation. In L6 cells subjected to LRP-1 small interfering RNA treatment for 48 h (LRP-1 silenced), LRP-1 mRNA levels were reduced by greater than 80% compared with control cultures treated with nonsense small interfering RNA (mock silenced). In addition, the 85-kDa transmembrane subunit of LRP-1 was undetectable in Western immunoblots of total protein lysates from LRP-1-silenced cells. Even though LRP-1 mRNA and protein levels were dramatically reduced in LRP-1-silenced L6 cells compared with mock-silenced controls, rpIGFPB-3 suppressed proliferation rate to the same extent in both LRP-1-silenced and mock-silenced cultures. Our results strongly suggest that, in contrast to data obtained for nonmuscle cell lines, the LRP-1 receptor is not required for IGFBP-3 to suppress proliferation of L6 myogenic cells.     

衡阳紫色土丘陵坡地不同土地利用方式对球囊霉素相关土壤蛋白分布的影响

为了明确衡阳紫色土丘陵坡地不同土地利用方式球囊霉素相关土壤蛋白土层分布模式及其影响因素,本试验选取自然恢复地、草地、灌草地、灌丛地和乔灌地5种不同土地利用方式样地,采集各样地0~10,10~20,20~40 cm土层土样,测定了土样球囊霉素相关土壤蛋白、土壤容重、土壤有机碳、全氮、C/N比、速效磷、土壤pH和土壤蛋白酶活性。结果表明：球囊霉素相关土壤蛋白含量为1.73~3.78 mg·g^-1,占土壤有机碳含量的14.05%~22.08%,是土壤一个重要碳库;球囊霉素相关土壤蛋白在不同土地利用方式和土层剖面之间差异显著;相关性分析表明球囊霉素相关土壤蛋白与土壤有机碳、全氮、C/N比、土壤蛋白酶、速效磷、土壤容重、土壤pH有显著相关性。研究结果表明,球囊霉素相关土壤蛋白是丛枝菌根真菌生长状况和土壤生态系统波动的一个重要指标。     

家蚕微粒子病流行因子的分析

对杂交蚕种生产中的家蚕微粒子病发生和流行情况进行了数量统计分析。通过对蚕种生产量与微粒子病的发生量 (淘汰量、有病合格量和有病总量 )、上一季蚕种生产中微粒子病的发生量与下一季蚕种生产中微粒子病发生量的相关系数分析 ,以及春季与秋季制种、蚕种场与原蚕区制种的微粒子病发生率的比较 (t测验 )表明 :当防治微粒子病的人为因素的作用被减弱时 ,蚕种生产量、上一季制种中微粒子病的发生、秋季制种和原蚕区等客观因素将成为家蚕微粒子病的流行的主要因子。原蚕区制种中微粒子病的防治技术体系也是目前亟待解决的问题     

固定效应对槟榔江水牛体重影响的研究

[目的]槟榔江水牛为我国目前为止发现的唯一本土河流型水牛,具有产奶性能高、肉用性能好的特点,为了进一步阐明槟榔江水牛的生长发育规律,本文收集云南腾冲县巴福乐槟榔江水牛2004~2011年生长发育数据资料,研究性别、月份和年度等固定效应对体重的影响。[方法]应用SAS分析性别、月份、年度等非遗传因素对槟榔江水牛体重的影响,并且用MTDFREML软件分析了固定效应值。[结果]本研究结果表明,槟榔江水牛性别对初生重具有显著影响,公犊平均初生重(35.04kg)显著高于母犊(32.63kg);月份对母牛初生重没有显著影响,公牛的效应值比母牛的较大。[结论]月份对槟榔江水牛的体重有显著的影响,可能与饲料的季节性供给有关。     

哺乳动物的克隆技术——哺乳动物克隆的原理、方法、影响因素及存在的问题

哺乳动物细胞克隆是20世纪末生命科学领域最引人注目的高新技术,该技术对于优良种畜的复制、减少试验用动物数目、动物遗传多样性保存及濒危动物挽救、转基因动物培育等方面具有重要意义。近年来克隆技术发展迅速,多种哺乳动物相继克隆成功,但也存在克隆效率太低、克隆动物表型正常而实质异常的问题。作者阐述了动物克隆的基本原理、操作方法及其相关影响因素,提出了解决相关问题的关键。     

用甲基丙烯酰氧乙基三甲基氯化铵接枝真丝的研究

为提高真丝纤维织物的抗菌防皱性能,根据真丝纤维蛋白质主体的结构,研究了以硝酸铈铵(CAN)为引发剂,甲基丙烯酰氧乙基三甲基氯化铵(DMC)单体接枝真丝的影响因素,并对DMC接枝真丝后的回潮率、单丝强力和泛黄指数进行了研究,用红外光谱分析了接枝真丝的化学结构。当DMC浓度为06mol/L,CAN的质量分数为10%,pH=3,温度60℃保温120min时,接枝效果较好。接枝后回潮率改善,但泛黄指数有上升趋向,单丝强力也有所下降。红外光谱分析表明单体已接枝到真丝纤维上。     

环境因素影响肉鸡生长的研究进展

就环境因素中温度、湿度、有害气体、光照和饲养密度对肉鸡生产性能的不利影响进行综述,并从内分泌、细胞体液反应、免疫、组织器官和营养代谢角度阐明不利因素影响肉鸡生产效果的机理。     

白细胞介素-8及其在动物疾病发生中的作用

白细胞介素-8(interleukin-8,IL-8)作为细胞因子,其在炎症和肿瘤性疾病的发生发展中发挥着重要作用。对其生物学功能和作用机制进行深入系统研究将为抗炎药物研发提供科学依据,为肿瘤治疗开辟新途径。作者就IL-8及其在动物疾病发生中的作用作一简要概述。