南方不同季节育雏鸡舍主要环境因子的变化研究

试验以有窗封闭式笼养育雏鸡舍为对象,于2018年3月~2019年1月开展研究鸡舍内环境的温度、相对湿度、二氧化碳(CO2)、氨气(NH3)、硫化氢(H2S)、二氧化硫(SO2)浓度和细菌总数,并分析环境因子之间的关系。结果显示:不同季节育雏舍内环境温度满足鸡群正常需要,鸡群成活率超过97%。夏季舍内相对湿度达82.48%,并且料肉比高于春季、秋季和冬季。春季、秋季和冬季CO2浓度易超标,不同季节舍内白天温度均高于夜晚,而白天CO2浓度低于夜晚。不同季节舍内环境温度分别与相对湿度、CO2浓度呈负相关和正相关关系。试验表明:有窗封闭式育雏鸡舍内不同季节雏鸡生长发育良好,但夏季湿度过高,春季、秋季和冬季舍内CO2浓度高于标准。建议夏季应合理控制舍内相对湿度,春秋冬季注意平衡舍内的保暖和通风工作。     

Effects of growth factors (EGF,PDGF-BB and TGF-beta 1) on cultured equine epithelial cells and keratocytes: implications for wound healing

Objective The physiologic mechanisms involving growth factors, including PDGF‐BB, EGF, and TGF‐β1, as potent mediators of fibroblasts and epithelial cells in corneal wound healing remain unknown. The goal of this study was to determine culture methods for equine epithelial cells and keratocytes and to investigate how exogenous growth factors influence proliferation of both cell types. Procedures Cell cultures were established from healthy corneas harvested from horses immediately following euthanasia and maintained using standard tissue culture protocols. To determine the effects of PDGF‐BB, EGF, TGF‐β1, keratocytes (1 × 10⁵/well) and epithelial cells (2 × 10⁵/well) were each cultured in 12 well plates and exposed separately to the growth factors. The cells were exposed to concentrations of EGF between 0 and 50 ng/mL; PDGF‐BB between 0 and 75 ng/mL; and TGF‐β1 between 0 and 10 ng/mL. Cell proliferation was measured using ³H‐thymidine assay and differences in growth determined using anova and Tukey's HSD test (P < 0.05). Results Epithelial cell and keratocyte cultures were successfully established. EGF maximally stimulated keratocyte and epithelial cells at 25 ng/mL and 5 ng/mL, respectively. PDGF‐BB maximally stimulated keratocytes and epithelial cells at 50 ng/mL and 5 ng/mL, respectively. TGF‐β1 inhibited keratocytes at 5 ng/mL and 10 ng/mL, and epithelial cells at 1 ng/mL and 2 ng/mL. Conclusions Methods were established to maintain epithelial cells and keratocytes in vitro. PDGF‐BB and EGF stimulate, while TGF‐β1 inhibits the proliferation of epithelial cells and keratocytes. These growth factors may play a role in maintenance and repair of the equine cornea.     

黄河三角洲新生湿地不同植被类型土壤的微生物分布特征

为探明黄河三角洲新生湿地土壤微生物分布特征,选取盐地碱蓬(Suaedasalsa)、柽柳(Tamarix chinensis)、芦苇(Phragmites communis)和拂子茅(Calamagrostis epigeios)4种湿地植被土壤,分春、夏、秋3个季节对其中细菌、真菌和放线菌数量组成和分布特征进行了研究。结果表明:不同植被类型湿地土壤中各类微生物数量差别明显,但总体上均偏少,而且优势种类非常明显,以细菌为主,放线菌居中,真菌最少;不同微生物数量上具有明显的季节分布特征,除拂子茅湿地细菌群落外,其他各群落数量均为夏季高,春、秋低;湿地土壤中微生物总量分布存在明显的根际效应,其中细菌的根际效应最为明显;土壤中氮和磷(总氮、总磷、速效氮、速效磷)含量对细菌的数量影响最明显;真菌分布与氮的含量关系密切,但与磷素关系不大;放线菌分布与氮含量相关性小,与磷素呈负相关;微生物数量与土壤pH值和电导率呈一定程度的负相关。本区土壤微生物分布与植被类型、土壤盐分和养分关系密切,且具有明显的季节动态。     

Serum vascular endothelial growth factor in dogs with soft tissue sarcomas

This work aimed to evaluate serum vascular endothelial growth factor (VEGF) in 25 dogs with soft tissue sarcoma, and in 30 healthy dogs. Blood was collected once time from the control animals and three times, in the same way, from animals with sarcoma. Blood count was performed in the blood collected, and serum VEGF was measured by enzyme‐linked immunosorbent assay quantitative method. Serum VEGF in control animals was similar to patients with soft tissue sarcoma. There was a reduction in serum VEGF after the sarcoma resection. There was positive correlation between serum VEGF and neutrophil counts, and negative between VEGF and hemoglobin content in animals with sarcoma. Animals with hemangiopericytoma showed higher serum VEGF levels compared to the patients with malignant peripheral nerve sheath. Circulating blood cells can contribute to elevate VEGF serum concentrations in dogs with soft tissue sarcomas and a possible role of VEGF in the angiogenesis of these tumors.     

影响鱼类生长的水质因子机理与控制

水产养殖在饲料稳定性差、养殖密度过大、换水不勤时,会导致饲料残渣和排泄物累积,引起水质恶化。水质的好坏主要表现为水的酸碱度值、溶解氧含量、化学耗氧量、透明度、氨氮含量、亚硝酸盐含量以及硫化物浓度等指标的变化。水质恶化极易引起鱼类发病,甚至死亡。笔者对主要水质因子影响鱼类生长的机理和控制途径进行了探讨。     

Delivery of growth factors using gene therapy to enhance bone healing

OBJECTIVE: To review the delivery of growth factors using gene therapy for enhancing long-bone fracture healing. STUDY DESIGN: Literature review. METHODS: MEDLINE and CAB Abstracts literature search (1980-2004). RESULTS: Non-union and infected non-union are relatively common complications of long-bone fractures in human and veterinary patients. Growth factors are cytokines that regulate many cell functions important in fracture healing. Exogenous growth factors can be delivered to the fracture site as recombinant proteins or using gene therapy. Recombinant human bone morphogenetic protein-2 and -7 (rhBMP-2 and -7), in particular, enhance fracture healing in numerous experimental and clinical studies. Some limitations with use of recombinant proteins may be overcome by use of gene therapy. Gene therapy involves delivery of the growth factor gene to cells at the fracture site using a viral or non-viral vector. The gene is then expressed (protein synthesis) by cells at the fracture site. Delivery of the BMP gene to the fracture site using gene therapy has been evaluated in laboratory animal models of non-union, with favorable results and without complications. CONCLUSION: Delivery of growth factors, particularly members of BMP family, to the fracture site using gene therapy may be a method to enhance fracture healing. Use of this technology may improve the prognosis for patients with long-bone fractures. CLINICAL RELEVANCE: Clinical application of gene therapy could improve the prognosis for human and veterinary patients with long-bone fractures, but has not been evaluated clinically.     

Factors associated with time to neonatal diarrhoea in French beef calves

A prospective study was carried out on 92 randomly selected beef herds in the Midi-Pyrénées region in France. The objective was to determine factors associated with time to neonatal gastroenteritis. By taking into account the “intra-herd” correlation in failure time (in the semiparametric Cox model), we identified 12 management risk factors associated with hazard of diarrhoea. Some previously have been identified, but “new” risk factors were feeding of corn silage and the incidence of diarrhoea in the last season. We used the two main approaches which are often reviewed: marginal and frailty Cox models. Our results show that these two models give different parameter estimates, so the choice of the model remains crucial.     

蛋鸡脂肪肝出血综合征的病因研究进展

蛋鸡脂肪肝出血综合征(FLHS)是一种代谢性疾病,营养、内分泌、遗传和环境等因素都可影响其发生。日粮中能量过高或蛋白不足是诱发FLHS的主要因素,能量、蛋白来源也影响FLHS的发生。日粮中脂肪酸来源影响FLHS的发生,动物性脂肪较易引起FLHS,适量添加植物油可降低肝脏脂肪含量。雌激素水平升高可引起肝脏脂肪含量增加,与FLHS存在一定的量效关系。甲状腺素和孕酮可降低肝脏脂肪含量,防止出血发生。FLHS易感品系UCD-3蛋鸡肯定了遗传因素对该病的影响。空间不充足或必要活动受限制,导致能量过剩是FLHS发生的重要诱因。肝脏脂肪沉积并不总是引起肝脏出血,脂质过氧化物分解生成大量脂质自由基引起细胞损伤,可能是肝脏脂肪含量升高导致出血的分子机制。     

对3个桑品种生理生态特征的比较研究

研究了湖桑32号、农桑14号和丰田2号等3个桑树品种的光合特征及叶绿素的部分参数。3个品种的光补偿点为3.58～50.10μmol/(m2.s),表观量子效率为0.022～0.051,湖桑32号>农桑14号>丰田2号;光饱和点为1 436.78～1 571.43μmol/(m2.s),丰田2号>农桑14号>湖桑32号;CO2补偿点为62.87～103.40μmol/mol,CO2饱和点为921.88～1 055.56μmol/mol,其中,湖桑32号的CO2补偿点和饱和点、羧化效率及二磷酸核酮糖羧化酶的最大再生速率(Pmax)均较显著高于其它两个品种;叶绿素相对含量丰田2号>农桑14号>湖桑32号,表明丰田2号单位叶面叶绿体数量较多,具有相对较大的光合潜力;光化学效率和光合电子传递效率分别为0.746 2～0.801 8、1.58～3.43,其中丰田2号的叶绿素荧光参数值显著高于其它2个品种,具有一定光适应和抗逆性能力。     

禽肉嫩度检测方法的探讨

针对目前禽肉品质检测中嫩度测定方法的多元化和检测数据的不可比性,就检测方法、采样方法以及影响检测结果的诸多因素进行一系列对比试验,结果发现熟样比生样检测结果要稳定,取样的准确性和剪切方向对检测结果影响显著.