一株奶牛“猝死症”病原菌的分离鉴定

针对黑龙江省垦区牡丹江分局某奶牛场奶牛猝死症开展了流行病学调查、临床症状、病理变化及实验室诊断等工作，证实了本次奶牛猝死症是由A型产气荚膜梭菌所致，为该牛场今后防治此病提供了科学依据。     

青海省酸牦牛奶中明串珠菌分离及其耐酸特性研究

从青海省部分牧区采集的32份牦牛酸乳样中,经形态学特征及生理生化特性分析,获得10株明串珠菌属菌株,分别鉴定为:Leu.mesenteroide subsp.dextranicum二株,Leu.lacti四株,Leu.paramensenteroide三株,Leu.mesen-teroides subsp.mesenteroide一株。并经耐受pH值3.09-3-2和Leu.paramensenteroides QH4-3-1两株菌呈现较强的耐酸性,为今后的明串珠菌耐酸性特征的进一步研究奠定了基础。     

公麝的生殖系统观察

解剖观察的结果表明 ,公麝的睾丸头朝上 ,附睾缘朝向后方。输精管末段形成梭形的输精管壶腹。副性腺发达 ,阴茎细而长 ,阴茎头呈左右扭转的圆锥形 ,尿道突细而长。香囊分泌物的气味可吸引异性     

有机铬的研究进展

铬是动物体必需的微量元素.Cr3+作为葡萄糖耐量因子(GTF)的活性成分强化胰岛素的生理功能,调节三大营养物质的代谢.与无机铬相比,有机铬易被动物体吸收,生物利用率高.大量研究结果表明有机铬在减少动物应激、改善胴体品质、提高母猪繁殖性能等方面有明显作用.     

猪源奇异变形杆菌的分离鉴定、耐药性分析及毒力基因检测

为确定屠宰场发病猪死亡原因,本研究对从死亡猪内脏中分离到的细菌,进行革兰染色镜检、生化鉴定和16SrRNA基因测序鉴定,并进行药敏试验、毒力基因检测及小鼠攻毒试验.结果显示,革兰染色镜检为细小或中等短杆状或丝状革兰阴性杆菌;生化试验特性分析及16SrRNA基因测序鉴定为奇异变形杆菌,命名为GZ2-2株.药敏试验结果显示...     

乳杆菌的分离及鉴定

从健康学龄儿童的新鲜粪便样品中分离得到6株乳杆菌,并对其进行属和种的鉴定。首先通过形态学观察及H2O2酶、糖发酵等生理生化试验对所分得菌株进行初步鉴定,然后利用16S rDNA序列同源性分析方法,对所分得菌株进行16S rDNA基因扩增与测序,测序结果与GenBank中该属内菌株的16S rDNA基因序列进行同源性分析,从而准确鉴定所分得菌株,并申请各菌株的GenBank登录号。经鉴定,其中1株为卷曲乳杆菌,2株为植物乳杆菌,1株为发酵乳杆菌,1株为黏液乳杆菌,1株为唾液乳杆菌。     

鸽新城疫病毒分离株F0裂解位点的基因克隆及序列分析

为探索鸽新城疫的流行特点,在分子水平上阐明鸽新城疫病毒分离株与鸡新城疫毒株之间的相互关系,我们用RT-PCR技术获得了分离株FO裂解位点附近300bp的基因片段,将其克隆到pUC19载体上得到一重组克隆pNDV21,序列分析表明,插入片段与鸡新城疫强毒Texas相应区域的同源性为87.7%;而与弱毒株D26/76及La Sota的同源性分别是91.7%和98%.其FO裂解点的氨基酸顺序为Giy Arg-Gln-Gly-Arg.证明该分离株属于新城疫弱毒.     

皖南花母猪生殖系统生长发育的研究

对皖南花母猪生死器官的生长发育进行了测定。结果显示：仔猪出生时卵巢的重量为１２．５～１４．９ｍｇ,卵巢重量吾现指数生长模式,１２０日龄后右侧卵巢重量和体积的生长明显快于左侧。仔猪出生时输卵管长度达到２．３０～２．４９ｃｍ,４５日龄为８．３～８．５ｃｍ,２４０日龄达到２１．３～２１．５ｃｍ,１８０日龄后右侧输卵管外径的生长速度明显快于左侧。子宫的的生长发育与日齿蝗一相关明显。血浆中ＧＨ和Ｔ４激素水平     

Age, growth and reproductive biology of the European conger eel (Conger conger) from the Atlantic Iberian waters

The European conger eel, Conger conger, is a fish widely distributed in the north-eastern Atlantic, being an important commercial and recreational fish species. A total of 85 juvenile congers eels were used in this study. Seventy-three congers were captured mainly by hook and pots in inshore waters (10–15 m depth) of the Iberian Peninsula (North Portugal and Vigo), monthly from March 1998 to March 2000. Another twelve specimens have been captured during a research cruise (R.V. “Capricórnio”) in summer 1999 by trawl at depths about 400 m in south Portugal. The length and weight of the congers eels ranged from 38 to 173 cm and 125 to 14,553 g, respectively. The observation of burnt otoliths under UV light proved to be a useful method for ageing conger eels. Marginal increment analysis was used to validate the annual pattern in the deposition of bright zones in the otoliths. Age for the congers ranged from 2 to 12 years. The VBF population growth curve estimates from the otoliths of the females gave results of L_∞ = 265 cm, k = 0.07 and t₀ = −1.20. Sex determination and gonadal development were obtained from histological analysis. All the specimens collected in the coastal shallow waters were females, either immature or in a developing stage. The ovaries contained oocytes in two main stages of development: a pre-vitellogenic stage and an early vitellogenic stage. The few males (n = 4) observed have been captured in the trawl fishery at deeper waters. The males possessed small cells spermatogonias and spermatocytes clustered in crypts in the testis scattered in a matrix of adipose tissue. The sexual steroids, 17β-oestradiol and testosterone, were measured in blood plasma samples by solid-phase radioimmunoassay. Both sexual steroids presented a high correlation with the sexual development stage in terms of maximum oocyte diameter and gonadosomatic index. This work presents for the first time, data on age, reproductive biology and endocrinology of conger eels captured in the west coast of the Iberian Peninsula.     

Effects of supplementary fennel (Foeniculum vulgare) essential oil in diet on growth and reproductive performance of the ornamental fish,Convict cichlid (Cichlasoma nigrofasciatum)

This study evaluated the effects of diet containing 0 (C: control), 75 (D₁), 100 (D₂), 125 (D₃) and 150 (D₄) mg kg^?1 F. vulgare essential oil on growth and reproductive performance of C. nigrofasciatum. A total of 225 Convict cichlids female with mean weight (1.65 ± 0.02 g) were distributed into 15 glass aquaria (15 fish tank^?1) in triplicate treatments. During 40 days of experimental period, fish fed at 3% of their body weight daily. At the end of experiment, growth indices, gonadosomatic index and reproductive indices were determined. The best feed conversion ratio was obtained in D₄ (1.19 ± 0.03, P < 0.05). The addition of F. vulgare essential oil did not have any statistical effects on other growth indices (specific growth rate, weight gain and condition factor). Total survival rates in all treatments and control were uniformly high, ranging from 93% to 97% (P > 0.05). F. vulgare essential oil has no negative effect on survival rate of C. nigrofasciatum. There were no significant differences among protein content of fish body (P > 0.05). The lowest value of fat content (26.5 ± 0.5%) was observed in D_2, and it had significant difference with control and other groups (P < 0.05). The ash percentage in treatments fed with F. vulgare essential oil were higher than control fish (P < 0.05). The highest moisture content was detected in D₄ (72.68 ± 0.19%) and D₂ (71.23 ± 2%) groups. Among the used dosage, D₄ was the most effective dosage that could significantly increase GSI (11.06 ± 1.55%), fecundity (340 ± 21) and hatching ratio (92.33 ± 1.63%). There were no significant differences in diameter of eggs among various treatments (P > 0.05).