In vivo and ex vivo assessment of the interaction between ivermectin and danofloxacin in sheep

The impact of an efflux pump-related interaction between ivermectin and danofloxacin on their intestinal transport (ex vivo) and disposition kinetics (in vivo) was assessed. Eighteen male Corriedale sheep were randomly assigned to one of three groups. Animals in Group A received 0.2mg/kg ivermectin by SC injection, those in Group B were given 6 mg/kg danofloxacin SC on two occasions 48 h apart and those in Group C were treated with both compounds at the same rates. Plasma concentrations of ivermectin and danofloxacin were measured by HPLC using fluorescence detection. Ex vivo intestinal drug transport activity was measured by the use of the Ussing chamber technique. Plasma concentrations of ivermectin in the first 6 days after injection tended to be higher in Group C than Group A. Contemporaneous treatment with ivermectin significantly increased systemic exposure to danofloxacin (AUC values were 32-35% higher) and prolonged the elimination half-life of danofloxacin (40-52% longer). Ex vivo, incubation with ivermectin significantly decreased the efflux transport of rhodamine 123, a P-glycoprotein substrate, in sheep intestine, but no significant effect of danofloxacin on transport activity was observed. Evaluation of the interaction of danofloxacin with the breast cancer resistance protein (BCRP) showed that pantoprazole and ivermectin significantly decreased danofloxacin secretion in the rat intestine. Thus, the ivermectin-induced reduction of danofloxacin efflux transport observed in this study may involve BCRP activity but the involvement of P-glycoprotein cannot be ruled out.     

犬IFN-α优化基因的真核表达及抗病毒活性的研究

本研究根据酵母系统密码子的偏嗜性,对成熟蛋白基因核苷酸序列进行密码子偏嗜性改造,利用毕赤酵母分泌型表达载体pPICZαC来表达犬IFN-α成熟蛋白基因。并采用非洲绿猴肾细胞(Vero) -水疱性口炎病毒(VSV)系统以细胞病变抑制法为基础来测定重组犬α干扰素的效价,同样方法测定了表达产物对PRV和CDV的抑制作用。本试验实现了犬α干扰素在酵母中的高表达,表达量高达58 mg/L,SDS-PAGE检测大小约为24 ku,比预测分子质量大,推测发生了糖基化。表达产物具有较强的种属特异性,在Vero细胞上对PRV具有较高的抗病毒活性,达到了3.6×10⁷ U/L,对CDV也有很好的抑制作用。本研究为犬IFN-α以后的临床应用研究奠定基础。     

Changes in nutrient balance,methane emissions,physiologic biomarkers,and production performance in goats fed different forage-to-concentrate ratios during lactation

The objective was to determine the effect forage-to-concentrate (F:C) ratio and stage of lactation on methane emissions, digestibility, nutrient balance, lactation performance, and metabolic responses in lactating goats. Twenty Murciano-Granadina dairy goats were used in an experiment divided into 3 periods: early (30 d), mid (100 d), and late (170 d) lactation. All goats were fed a diet with 35:65 F:C (FCL) during early-lactation. Then, 1 group (n = 10 goats) remained on FCL through mid- and late-lactation while the other group (n = 10 goats) was fed a diet with 50:50 F:C at mid-lactation (FCM) and 65:35 (FCH) at late lactation. A greater proportion of concentrate in the diet was associated with greater overall intake and digestibility (P < 0.05). Energy balance was negative in early-lactation (−77 kJ/kg of BW^0.75, on average) and positive for FCL at mid- and late-lactation (13 and 35 kJ/kg of BW^0.75, respectively). Goats fed FCM and FCH maintained negative energy balance throughout lactation. Plasma concentrations of non-esterified fatty acids at mid-lactation were greater for FCM than FCL (680 mEq/L), and at late-lactation concentrations were greater for FCH and FCL (856 mEq/L). A similar response was detected for plasma β-hydroxybutyrate. Methane emission was greater (P < 0.05) for FCM than FCH (1.7 g CH₄/d). This study demonstrated that differences in F:C across stages of lactation lead to distinct metabolic responses at the level of the rumen and tissues.     

Trichinella: differing effects of antigens from encapsulated and non-encapsulated species on in vitro nitric oxide production

Trichinellosis is a cosmopolitan zoonotic disease affecting a wide variety of animals, including man. Non-encapsulated and encapsulated species diverge with respect to their developmental strategies. Little is known at the molecular level about parasite-derived mediators responsible for host muscle cell transformation occurring during trichinellosis. In this context, host-parasite relationships in Trichinella-infected animals could be related to different host-immune and cell mediators, e.g. nitric oxide (NO). Here, we investigate the stimulatory/inhibitory role of L1 antigens from four encapsulated (T. spiralis, T. britovi, T. nelsoni and T. nativa) and one non-encapsulated (T. pseudospiralis) Trichinella species on NO production from rat macrophages in vitro. Our results demonstrate that encapsulated and non-encapsulated Trichinella species differ in their capacity to stimulate the secretion of NO from host macrophages. Biological significance of these differences should be further assessed in the available experimental models.     

中药抗炎作用及其机制研究进展

20世纪后，人们对炎症的研究逐渐转移到了炎症发生、发展的机制和药物抗炎机制方面，从而开拓了一个十分重要的研究领域，为防治畜禽疾病提供了新的策略。目前。临床治疗中除肾上腺皮质激素类与非甾体类抗炎药物（NSAID）以外，部分中药也逐渐应用于抗炎。由于许多化学合成药物具有较强毒副反应，人们更加重视从天然药物中开发毒副作用较小的抗炎药物，用现代科学方法研究中药抗炎机制与临床应用是当今世界新药开发的热点。     

八点黑獭兔不同发育时期盲肠组织结构变化的研究

为了研究獭兔不同发育时期盲肠组织结构变化特点,总结其发育规律,采用石蜡切片、HE染色技术,对相同条件下饲养的不同生长阶段(出生后1,15,30,60d)獭兔各6只进行解剖,并在显微镜下观察其盲肠组织结构.结果发现,獭兔盲肠黏膜的单层柱状上皮细胞的高度、杯状细胞的体积都随年龄的增长而变大,半环形皱襞间的距离随着年龄的增长逐渐变小,皱襞的长度和体积也随年龄增长有所增加.此外还发现,随年龄的增长八点黑獭兔盲肠蚓突内的淋巴小结数目明显增多,黏膜下层内的淋巴小结和弥散淋巴组织随年龄增长也越来越多,黏膜皱襞变得密集.     

养猪场户对生猪良种补贴政策满意度影响因素分析

作为补贴对象和直接受益者,养猪场户对政策的满意程度直接影响到政策的实施情况及效果,同时也是政策进一步调整优化时需要考虑的重要因素。本文基于养猪场户的调研数据,通过构建Logit模型,分析影响养猪场户对生猪良种补贴政策满意度评价的主要因素,结果发现:从事养猪年限、对人工授精技术掌握程度、对供精单位技术服务满意度、对供精单位配送服务满意度、对生猪良种补贴政策了解程度等因素对养猪场户的满意度评价有显著影响。     

披碱草属野生种质材料在干旱与半干旱区适应性评价

应用灰色理论系统,以搜集自我国8省区的38份披碱草属植物野生种质材料为研究对象,对其株高、叶面积生长动态、草产量、茎叶比、鲜干比及种子产量进行灰色关联度分析.结果表明,株高从拔节期到抽穗期增幅较大,而叶面积从分蘖期到拔节期增幅较大;38份材料鲜草及干草产量差异较大,变异系数分别为39.275％和43.087％;大部分种质材料茎叶比在1.0～2.0之间;不同材料种子产量的变异系数较大;产量与各主要农艺性状的关联度大小顺序为:鲜干比＞种子产量＞茎叶比＞叶面积＞株高.综合分析发现,适应性较好的种质材料有NMC32、BJT37、QHD19、SXD36、XJD11、XJD15、XJS8、XJT2、XJE13和XJD5.     

O型口蹄疫病毒VP1 T细胞与B细胞表位基因双拷贝串联表达产物的免疫应答

以一株O型口蹄疫病毒(FMDV)外壳蛋白VP1基因为模板,合成与细胞免疫及体液免疫相关抗原表位肽基因:21-40肽(20AA)和141-160肽(20AA)基因序列,运用基因工程技术构建了含有串联结构21-40(20AA)～141-160(20AA)～21-40(20AA)～141-160(20AA)的2020-2020VP1融合基因表达载体r2020-2020,转化宿主菌BL21(DE3)RIL后诱导表达,表达产物经SDS-PAGE及Western Blot分析显示重组融合蛋白的分子量约为18Ku.动物实验表明,较小剂量的融合蛋白就能诱导豚鼠产生特异性T淋巴细胞增殖反应及抗FMDV中和抗体,证明该融合蛋白可同时激活细胞免疫及体液免疫反应,具有开发成为抗FMDV疫苗的应用价值.     

Orbital (retrobulbar) meningioma in a Simmental cow

A 12-year-old Simmental cow was presented with a moderately firm irregular whitish mass of approximately 5 cm in diameter, occupying the right orbit. Microscopically, a poorly differentiated neoplasm was observed. The immunohistochemical panel included cytokeratins, vimentin, epithelial membrane antigen, Factor VIII, CD34, Mart-1, Melan A, smooth muscle actin, desmin, chromogranin, neuron-specific enolase, S-100 protein, and MIB-1. The neoplasm was negative for all of them, with the exception of vimentin and S-100 protein. Transmission electron microscopy revealed abundant desmosomes. These findings support the diagnosis of orbital (retrobulbar) meningioma.