肝素或钙离子载体诱导牛、羊冻精体外获能的研究

本文采用肝素或钙离子载体(I-A)诱导牛、羊冻精体外获能,根据对去透明带仓鼠卵的穿透情况评定获能效果,并用台盼蓝·姬姆萨(TG)染色观察了精子的死活及顶体状态.结果发现,牛、羊冻精经肝素或I-A处理后与卵子一起培养,2 h穿透仓鼠卵,4 h开始形成雄原核,6 h形成发育良好的雄原核.牛冻精用50μg/mL肝素及0.1μmol/L I-A处理效果最好,穿透率分别为72.8％和92.3％;羊则以20μg/mL肝素及0.3μmol/L I-A为宜,穿透率分别为73.1％和68.O％.咖啡因与I-A或肝素并用均有协同作用,能提高精子的穿透能力,并能促进卵内原核的发育.肝素和I-A均能在体外诱导牛、羊冻精的顶体反应,有顶体反应活精子百分率与穿透率呈强正相关,羊冻精比较脆弱,获能处理后活力较低.     

Calcium ions are involved in egress of Babesia bovis merozoites from bovine erythrocytes

Bovine babesiosis is a livestock disease known to cause economic losses in endemic areas. The apicomplexan parasite Babesia bovis is able to invade and destroy the host’s erythrocytes leading to the serious pathologies of the disease, such as anemia and hemoglobinuria. Understanding the egress mechanisms of this parasite is therefore a key step to develop new therapeutic strategies. In this study, the possible involvement of Ca²⁺ in the egress of B. bovis merozoites from infected erythrocytes was investigated. Egress was artificially induced in vitro using calcium ionophore A23187 and thapsigargin to increase Ca²⁺ concentration in the cytosol of the parasite cells. The increased intracellular Ca²⁺ concentration following these treatments was confirmed using live cell Ca²⁺ imaging with confocal laser scanning microscopy. Based on our findings, we suggest a Ca²⁺ signalling pathway in the egress of B. bovis merozoites.     

钙离子载体及咖啡因对绵羊精子获能的影响

通过添加不同浓度(0.05、0.1、0.2、0.5、1、5、10μmol/L)的钙离子载体(A23187,IA)及2 mmol/L咖啡因,探讨不同作用时间其对绵羊精子体外获能的影响。结果发现,IA浓度越高,精子的体外获能率越高,顶体反应率越低,活力越低,死精子就越多;而延长作用时间对获能、顶体反应的影响不明显。IA和咖啡因共同作用后,咖啡因能够促进IA诱导顶体反应的发生。建议用IA诱导绵羊精子获能时,其浓度以0.05~0.2μmol/L为宜,作用时间1 min。     

Acute polyneuromyopathy with respiratory failure secondary to monensin intoxication in a dog

Objective

To describe a successfully managed case of polyneuropathy and respiratory failure secondary to presumed monensin intoxication.

Case Summary

A 9‐month‐old Australian Shepherd was evaluated for progressive generalized weakness and respiratory distress. Several days preceding presentation, the dog was seen playing with a monensin capsule, and had free access to a barn where the product was stored and where chewed capsules were subsequently found. The dog was presented with flaccid tetraparesis, hyperthermia, and severe respiratory distress. Bloodwork and urinalysis revealed marked increase in serum creatine kinase concentration and presumed myoglobinuria. Cardiac troponin I level was markedly increased. Management included mechanical ventilation for 5 days, fluid‐therapy, active cooling, antimicrobial therapy, analgesia, gastroprotectants, antiemetics, enteral feedings, continuous nursing care, and physiotherapy. Intravenous lipid rescue therapy was administered with lack of improvement in respiratory function and muscle strength. The patient completely recovered and was discharged after 12 days of hospitalization.

New or Unique Information Provided

Monensin intoxication should be considered in the differential diagnosis of acute polyneuromyopathy and respiratory failure in dogs with access to this compound. Respiratory failure secondary to monensin intoxication does not necessarily carry a poor prognosis if mechanical ventilation can be provided as a bridge until return of respiratory function is achieved.     

透明带诱导绵羊精子顶体反应的研究

为探讨绵羊透明带（zona pellucida,ZP）对其精子顶体反应的诱导作用,实验分为3组：（1）不经获能处理的精子与透明带共孵育;（2）精子经获能处理后与透明带共孵育;（3）不经获能处理的精子与透明带共孵育,然后IA23187（添钙离子载体,calcium ionophore A23187）,来观察透明带对精子顶体反应的诱导效果。结果显示获能与否并不影响透明带对精子顶体反应的诱导效果,添加IA23187后,顶体反应(acrosome reaction,AR)升高,但差异不显著（P>0.05）。说明透明带可诱导绵羊精子(无论获能与否)发生顶体反应,IA23187不能提高透明带对顶体反应的诱导作用。     

Studies on synchronous egress of coccidian parasites (<Emphasis Type="Italic">Neospora caninum,Toxoplasma gondii,Eimeria bovis)</Emphasis> from bovine endothelial host cells mediated by calcium ionophore A23187

Neospora caninum, Toxoplasma gondii and Eimeria bovis are coccidian parasites of veterinary importance. Tachyzoites of N. caninum and T. gondii and sporozoites of E. bovis are able to invade and replicate in endothelial cells in vivo and in vitro. As it holds true for all eukaryotic cells, the survival of parasitized host cells and the parasites themselves should be dependent on ion balances, especially on extra- and intracellular calcium concentrations. Addition of the calcium ionophore A23187 reliably did release merozoites from mature N. caninum and T. gondii meronts grown in cultured primary bovine umbilical vein endothelial cells (BUVEC). Extent and time course of merozoite release depended on both, maturity of the meronts and concentration of the calcium ionophore. Attempts, however, to achieve synchronous release of merozoites from E. bovis first generation meronts by ionophore treatment failed, suggesting a different biological behaviour of this parasite. According to microscopical observations, the quite variable time of E. bovis macromeront maturation and a hampered merozoite exit owing to dense parasite-induced cytoskeleton elements surrounding the meront may be a reason for the lack of inducible synchronous release. Electronic supplementary materials The online version of this article (doi: ) contains supplementary material, which is available to authorized users.     

肝素和钙离子载体诱导波尔山羊精子体外获能和体外受精

运用肝素、钙离子载体（IA）协同咖啡因诱导波尔山羊精子体外获能，利用去透明带金黄地鼠卵穿透试验检测了精子的获能效果。结果发现：精卵孵育4h和6h时的穿透率均高于2h时的穿透率；肝素和钙离子载体对精子获能有明显的促进作用，与未添加组相比差异极显著（P〈0．01）；20mg／L和50mg／L的肝素剂量组，去透明带金黄地鼠卵穿透率为64．7％、68．4％；钙离子载体的添加剂量在0．3μmol／L时，穿透率达到68．2％；咖啡因与肝素、钙离子载体具有明显的协同作用。将获能的精子与山羊卵母细胞进行体外受精孵育17h，也获得了60％以上的受精率。     

Rumen fermentation and liveweight gain in beef cattle treated with monensin and grazing lush forage

Objective To determine the prevalence of subacute rumen acidosis (SARA) in beef cattle grazing lush pasture and the effect of monensin on reducing SARA and improving animal performance. Design Commercial Angus and Murray Grey steers received a monensin slow‐release capsule (n = 19) or remained untreated (n = 19). Cattle grazed an oats crop or tetraploid ryegrass pasture for a total of 91 days. Rumen fluid pH, volatile fatty acids (VFA) and lactic acid concentrations and body weight data were collected prior to treatment and again 28, 56 and 91 days after treatment. Changes in measures over time were analysed using mixed model repeated measures analysis. Differences in average daily gain between treatment groups were determined. Results The prevalence of SARA was low during the study, with only one animal satisfying criteria for SARA at one time point. Cattle treated with monensin capsules were 11.9 kg heavier at the completion of the study compared with untreated controls (414.5 ± 3.88 kg vs 402.6 ± 4.03 kg, P = 0.04). Rumen VFA and L‐ and D‐lactate levels did not differ between cattle treated with monensin and untreated cattle. However, the ratio of propionate to acetate plus two times butyrate was higher (P < 0.001) when cattle were treated with monensin. Conclusions Subacute rumen acidosis was not consistently detected under the conditions of the study. The higher body weight of cattle treated with monensin may have been due to improved energy utilisation of the pasture, indicated by increased propionate proportions in the rumen, rather than prevention of SARA.     

离子载体药物对家鸭球虫病治疗效果比较

鸭球虫病是由多种鸭艾美耳球虫寄生于鸭肠上皮细胞引起的一种原虫病,给养禽业带来巨大的经济损失。为了解离子型抗球虫药物对鸭球虫病的防治效果,在模拟家鸭笼养的环境条件下,选用莫能霉素、盐霉素、马杜拉霉素、拉沙里菌素、那拉霉素等5种离子载体药物进行试验。试验结果表明,5种离子载体类药物对鸭球虫病均有很好的防治效果,并且马拉霉素等对家鸭的增重也有一定效果。     

离子载体对肉牛能量代谢的影响

为了比较莫能霉素、盐霉素和拉沙里菌素3种离子载体对肉牛能量代谢的不同影响,以4头30～35月龄、体重380～450kg的西门塔尔×中国黄牛杂交一代公牛为试验动物,采用4×4拉丁方设计,应用呼吸测热室进行能量平衡试验。结果表明:莫能霉素、盐霉素和拉沙里菌素对总能消化率没有影响(P>0.05);分别使消化能转化为代谢能的效率提高2.07%、1.85%和2.07%(P<0.05);使甲烷能/进食总能比例减小15.1%、17.6%和19.3%(P<0.05);使代谢能产热率降低1.76%、2.92%和3.87%(P>0.05),使日粮总能沉积率提高3.30%、5.62%和8.07%(P>0.05)。