Potentiation of metrazol convulsions in chickens after neonatal injections of cycloheximide or glutamate

Chickens which received forebrain injections of cycloheximide or glutamate when newly hatched were found to be more susceptible to metrazol-induced convulsions at 6–8 weeks of age. It is possible that these changes in convulsive threshold are related to alterations in dopaminergic transmitter systems found in the birds.     

Diphenylhydantoin facilitation of labile, protein-independent memory

Diphenylhydantoin (DPH 10⁻⁴M) administered subcutaneously to chicks 5 min after a one-trial passive avoidance learning task successfully counteracted anmesia induced by pretreatment 5 min before learning with ouabain or cycloheximide (CXM). Biochemical assays confirmed that in chick forebrain homogenate DPH at concentrations of 1 and 5 × 10⁻⁴M enhanced Na⁺/K⁺ ATP'ase activity. Since both DPH and ouabain inhibit post-tetanic potentiation, the results support the hypothesis of an initial labile phase of memory based on sodium pump (Na⁺/K⁺ ATP'ase) activity. DPH was less effective in counteracting ouabain-induced amnesia if administered later than 10 min after learning and CXM-induced anmesia if administered later than 30 min after learning. This suggests that the effect of DPH on CXM-induced anmesia is through enhancement of Na⁺/K⁺ ATP'ase activity. It was suggested that the possible hyperpolarization of membrane potential associated with sodium pump activity may serve to mark the labile memory trace, enabling formation of a more permanent trace through protein synthesis.     

饮水硼对动物空肠发育的影响

由饮水途径添加硼,研究硼对动物空肠发育的影响。实验取240只1日龄固始鸡,随机分为4组,分别在饮水中添加0、100、200、400 mg/L硼,试验期42 d,每周末每组取试验鸡6只,颈静脉放血致死,取空肠Bouin液固定,制作石蜡切片,HE染色,显微观测、摄影。结果:100 mg/L组空肠绒毛和肠腺的长度显著(P<0.05)或极显著(P<0.01)大于同日龄对照组。400 mg/L组空肠绒毛和肠腺的长度显著(P<0.05)或极显著(P<0.01)小于同日龄对照组(P<0.01)。7～28日龄400 mg/L组空肠出现绒毛上皮细胞肿胀、结缔组织水肿、毛细血管扩张、肠腺囊肿等病变。实验表明:饮水添加100 mg/L硼对固始鸡空肠绒毛及肠腺发育有明显的促进作用;添加400 mg/L硼会引起机体硼中毒,对固始鸡空肠绒毛及肠腺发育有明显抑制和毒害作用,严重影响机体的消化吸收功能。     

饲养方式对鸡纹状体神经细胞形态的影响研究

目的：研究不同饲养方式对鸡新纹状休（MNH）神经细胞树突棘的影响。方法：选择刚孵出的White Leghorn鸡18只，随机分为三组，每组6只，对照组（soc 7day）同笼群养7天，（iso 4day）组隔离单笼饲养4天，（iso 7day）组隔离单笼例养7天，分别于第4天和第7天将其处死并灌注固定，采用5％Lucifer Yellow对MNH神经细胞进行细胞内染色，并用共聚焦激光扫描显微镜进行扫描观察，对神经细胞树突棘进行分类、测量和统计分析。结果：（iso 4day）组中各种树突棘Dn、L、Dh的平均值均较对照组大（t=6．99；16．70；19.7均〉2．58，p〈0．01）；树突棘密度（n／100μm）在中间段树突上和全部树突段上与（iso 7day）组比较较小，差异有显著性（U=2．12，2．33均〉1．96；p〈0．05．）。（iso 7day）组与（soc 7day）组比较，各种树突棘Dn、T型树突棘长度L、S型和M型树突棘茎径Dn平均值均较对照组大，差异均有极显著性（t=12．28; 9．03；10．63；9．02均〉2．58，p〈0．001．）。结论：社会接触和相互学习能影响脑MNH神经细胞初戎的发育成长，提高其兴奋性突触后电位。提高突触间的传递效率，并能促使M型、S型树突棘向T型转化。     

A possible physiological mechanism for short-term memory

Memory formation for a passive avoidance task in day-old chickens is shown to be inhibited by intracranial injections of very low concentrations (1 and 2 mM) of potassium chloride. The effects occur early after learning, in the first of a postulated three phase sequence of memory formation. Concentrations between 2.5 and 5.0 mM KCl inhibit the second of the three phase sequence. Potassium chloride concentrations lower than 1 mM or comparable to normal CSF levels (7 mM) produce no effects on memory. Concentrations of sodium chloride different from normal CSF concentrations in the young chick also produce small but consistent memory deficits, the effects being independent of those due to potassium chloride. An argument is made for a mechanism of short-term memory formation involving afferent post-tetanic hyperpolarization which is inhibited by potassium accumulation at synapses caused by glia inactivation.     

我国SPF种鸡群研究进展

目前,我国有大小不同规模的SPF种鸡场十几家,但由于我国还没有自己的SPF种鸡群,这些单位不得不从外国引进SPF种蛋进行建群和更新换代,这样,不仅花费大量的外汇,还将受控于外国之下。近年来,我国对这方面的研究较快,1993年,中国农业科学院哈尔滨兽医研究所在国内首次采用普通种鸡群(京白鸡)为原材料,经疫病净化试验、生物学敏感性试验和选育培育试验等方法,用隔离器培育我国SPF种鸡基础群。1996年,在培育出的SPF种鸡基础群的基础上开展了我国SPF种鸡群培育的研究工作,并已取得了阶段性进展。     

Morphological, stereological and radiological changes in pinealectomized chicken cervical vertebrae

Considerable evidence supports the hypothesis that melatonin plays an important role in osteogenesis. We carried out an experiment to investigate histological and radiological changes in the cervical vertebrae of pinealectomized chickens. Thirty new-hatched chicks were divided into two groups: pinealectomized group (n=15) and nonpinealectomized control (n=15). Surgical pinealectomies were performed in Hybro broiler chickens at the age of 3 days. At 8 wk, one animal from each group was examined using computed tomography scanner to obtain density histograms of four consecutive vertebrae between the 4th and 7th cervical vertebral segments of chickens. At the end of the study, all animals were killed for subsequent measurement of bone mineral density (BMD) and macroscopic, radiographic and histopathological evaluation of specimens. We found that the profile of the density histogram in nonpinealectomized control group showed a spike profile for the vertebral body, indicating an increase in the amount of higher density tissues in this region, while a plateau-shaped profile was obtained for the vertebral body in pinealectomy group, indicating the presence of heterogenous bone tissue. Accordingly, the mean value of BMD in pinealectomy group was significantly lower at the vertebral body in chickens compared with control subjects (P<0.001). At the end of the experiment, almost all of the chickens in pinealectomy group developed a scoliotic curvature and the mean weight and length of the cervical vertebral bodies of the pinealectomized chickens were significantly lower than those of control group (P<0.001). Although the numerical density of osteocytes and osteoblasts in pinealectomy group was significantly higher than that from the control group, total number of osteocytes but not osteoblasts in cervical vetrebrae from pinealectomized animals was significantly lower than that from nonpinealectomized control animals (P<0.05). In conclusion, the results of the current study demonstrated for the first time pinealectomy-induced histomorphometrical changes in chicken vertebral column using stereological methods, suggesting that pineal gland/melatonin may have an osteoinductive effect on bone formation, but further studies are needed to elucidate the relationship of our findings with some disorders such as postmenopausal and/or senile osteoporosis.     

Enterococcus faecalis clones in poultry and in humans with urinary tract infections, Vietnam

Enterococcus spp. as pathogens have increased, but the sources of infection often remain unclear. To investigate whether poultry might be a reservoir for E. faecalis-associated urinary tract infections (UTIs) in humans, we characterized E. faecalis isolates from patients in Vietnam with UTIs during January 2008-January 2010 and poultry living in close contact with them by multilocus sequence typing (MLST), pulsed-field gel electrophoresis, analysis of antimicrobial drug susceptibility patterns, and sequencing of virulence genes. In 7 (23%) of 31 UTI cases, we detected identical MLST, indistinguishable or closely related pulsed-field gel electrophoresis patterns, and similar antimicrobial drug susceptibility patterns. Isolates from urine and poultry showed identical virulence gene profiles, except for 1 variation, and individual genes showed identical sequences. The homology of isolates from urine and poultry further indicates the zoonotic potential and global spread of E. faecalis sequence type 16, which recently was reported in humans with endocarditis and in pigs in Denmark.     

分离病鸡3株大肠埃希菌的鉴定及毒力和细胞毒测定

目的分离病鸡中3株大肠埃希菌和鉴定其对小鼠的致病力及对Vero细胞毒性作用.方法将按常规细菌的分离并鉴定的3株大肠埃希菌,接种至昆明系小鼠体内做毒力试验,计算死亡率和LD50(50%致死量).采用微量单层细胞培养法测定细菌上清液的细胞毒性作用.结果分离的3株细菌生物学性状均符合大肠埃希菌.分离的3株细菌对小鼠致病率为100%;菌量达6×1011CFU/L时死亡率为100%;LD50为1.5×1010 CFU/L.分离的3株细菌对2株细胞均无细胞毒性作用.结论分离的3株致病性大肠埃希菌与O157∶H7 株对小鼠致病力相似,可能是潜在的人类的传染源.