日本对虾内陆养殖的实验室模拟研究

我们将日本对虾进行实验室桶养作模拟内陆养殖试验。发现日本对虾可以顺利地养殖到体长５－７厘变,然后短人存活率急剧降低,这一现象与我们海边虾塘养殖所得到的结果极为一致,我们称之为“５－７”现象。     

青海省海南地区近30年≥0 ℃积温变化趋势分析

积温是作物与品种特性的重要指标之一,对积温农业气象重要指标的研究,对于指导农牧业生产具有十分重要的现实意义。本研究通过利用青海省海南藏族自治州共和、兴海、贵南、同德和贵德5县气象站的地面观测资料,对该地区近30年来≥0 ℃年积温的变化,主要农作物、牧草生育期的变化及其生育期≥0 ℃的积温变化做了分析,得出该地区大部分农作物及牧草的生育期有所缩短,开始期有所提前。由于近10年该地区升温明显,热量条件充足,各地≥0 ℃年积温有所增加,农作物及牧草发育期的积温增多,为该地区农作物及牧草的生长发育提供了充足的热量条件,对于该地区适时调整农牧业结构提供了依据。     

不孕症奶牛抗卵巢抗体的检测及临床意义

为探讨奶牛不孕症与ＡＯＡｂ的关系,用放免法检测啊１４例原发性不孕、１０例继发性不孕奶牛血清ＡＯＡｂ,并与正常妊娠组对照。实验表明,ＡＯＡｂ阳性１０例,总阳性率为４１．６７％,ＡＯＡｂ为原发性不孕相关,与继发性不孕无明显关系。结果提示,ＡＯＡｂ的存在是奶牛原发性不孕的重要病因。     

益生芽孢杆菌对雏鸡红细胞免疫及免疫器官的影响

Singel(1981)等发现,人红细胞与白细胞一样,也具有重要的免疫功能,其基础是红细胞表面的C3b受体。国内的郭峰等许多学者也发现了人红细胞上存在C3R,并建立了一系列检测方法(郭峰等,1993)。机体的免疫系统是由免疫细胞和免疫分子组成的一个完整的免疫网络,由于新生雏鸡免疫生理的特殊性,各种应激因素易使其潜伏感染转化为活动感染(M·S霍夫斯塔,1980)。因此,小鸡免疫功能的调节主要在于如何增强机体免疫性。目前,已有学者研究开发免疫调节剂或增强剂或提高机体免疫性以达到防病、治病的目的。微生态制剂是否对鸡免疫功能有影响是一个值得…     

脂溶性维生素对水生生物抗氧化系统影响的研究

<正>脂溶性VA、VD、VE和VK是一类化学结构不同,营养作用和生理功能各异的低分子有机化合物,是人类和动物不可缺少的一类营养物质。近年来的研究表明,脂溶性维生素除了发挥其经典作用之外,还具有抗氧化或氧化作用。本文就脂溶性维生素对水生生物抗氧化系统影响的研究做一综述。     

搜爆犬训练应把握好“四个奖励点”

在搜爆犬的初期训练中,为了尽快提高训练犬的兴奋性,培养出犬对训练物品的衔取欲和占有欲,对犬的奖励要做到充分、及时、准确,恰当地把握好强化的量、点和时机,以达到预期的训练效果.具体来讲,要注重做到以下"四个奖励点"的把握.     

Porcine parvovirus infection in a commercial piggery

Abstract

Extract

Madam:– We have recently been involved in a consultative role with a 60-sow commercial piggery. Over the year preceding the incident recorded here, this unit had approximately doubled in size by the purchase of improved large white gilts. An infertility problem involving irregular returns to service and small litter sizes was first noted around Christmas 1984. In early January 1985 all the adult stock were bled and serological tests undertaken. There was no evidence of infection with Aujeszky's disease virus or leptospires, but 42 sows had haemagglutination inhibition (HI) titres(2 Joo, H.O., Donaldson-Wood, C. and Johnson, R.H. 1976. A standardised haemagglutination inhibition test for porcine parvovirus antibody. Aust. vet. J., 52: 422–424.  [Google Scholar]) of >320 against porcine parvovirus (PP), and were considered to have been actively infected. (1 Johnston, R.H., Donaldson-Wood, C., Joo, H.O. and Allender, U. 1976. Observations on the epidemiology of porcine parvovirus. Aust. vet. J., 52: 80–84.  [Google Scholar]) Seventeen other gilts and sows in their second pregnancy had titres ?320 and were considered to be still susceptible to infection. These animals were bled again 75 days later and HI tests on the paired sera showed that 15 of the 17 had now scroconverted (minimum titre 1,280). Eleven of these animals were in early to mid-pregnancy during the period of seroconversion. Five of these animals subsequently failed to farrow, and the remaining six produced a mean of only 6.5 (S.D. 2.8) live piglets at birth. In contrast the two animals which did not seroconvert, and four other previously infected gilts with HI titre of >10,240 at the first bleeding, produced a mean of 9.8 (S.D. 1.7) live piglets. This was considered a satisfactory live birth rate for this age group, and was significantly higher (Student's t-test; P<0.05) than for the six sows which seroconverted and produced live pigs.     

Molecular taxonomic relationships of Psoroptes and Chorioptes mites from China based on COI and 18S rDNA gene sequences

In this present study, the mitochondrial DNA gene cytochrome coxidase subunit I (COI) and the small subunit ribosomal RNA (18S rDNA) gene were used to determine the taxonomic relationships of Psoroptes and Chorioptes mites from China. The neighbor-joining and maximum-parasimony approach were used to evaluate the evolutionary relatedness among different hosts in the genera Psoroptes and Chorioptes. Phylogenetic analysis showed that Psoroptes cuniculi and Psoroptes natalensis may be two different species within the genus Psoroptes, and Chorioptes texanus and Chorioptes panda are different species within the genus Chorioptes.     

高山草原放牧率与群落物种丰富度

选择甘肃省肃南裕固族自治县甘肃马鹿(Cervus elaphus kansuensis)养殖场冬季牧场不同牧压梯度的6个样地,采用巢式样方法调查草地植物群落的物种数,研究了甘肃马鹿山地草原放牧系统放牧率与草地群落物种丰富度的关系。结果表明,放牧强度梯度上,冬季牧场物种数随取样面积的增大而逐渐增加,放牧减轻导致物种增幅上升,放牧对物种丰富度的贡献率提高。高山草原的最小取样面积为0.71～1.54 m2,各放牧率样地物种数的变化分别在0.16～0.32和0.32～0.64 m2范围内最剧烈。物种数随放牧增强呈下降趋势,在放牧率2.45 AUM·hm-2出现拐点,拐点两侧放牧对物种多样性具有不同的作用规律,2.45 AUM·hm-2为高山草原适宜的放牧率。在牧场尺度上,当面积超过2.56 m2,改善放牧管理对物种丰富度的增加没有作用。     

猪伪狂犬病毒传入猪场的风险评估模型研究

为评估未来3年内猪伪狂犬病毒(PRV)变异株传入某阴性种猪场的风险,通过文献分析,结合国家定点监测分析结果和专家经验,建立了PRV传入猪场的风险路径。以该风险路径为依据,采集和整理与风险路径中各风险因素相关的数据,开展了定性分析评估。结果发现,PRV通过未经野毒抗体检测的种猪、外购精液,以及气溶胶和带毒老鼠传入的风险极高。