美洲鲟幼鱼摄食试验

投喂三种商品性的鲑鳟鱼类饲料、一种试验性的甲壳动物饲料、与一种活饵料(颤蚓)对照，作美洲鲟幼鱼生长和存活试验，结果证明，某些加工饲料，特别是一种半潮湿性饲料，能作为美洲鲟开始摄食时头40天的饲料。虽然投喂半潮湿性饲料时鲟鱼的生长率比喂活饵料要低，但存活率仍一样；而且可以避免过去把鱼从喂活饲料转移到喂加工饲料时所产生的高死亡率。干饲料不能被很好利用，而且幼鱼生长率和存活率都很低。     

犬瘟热新型治疗方法

犬瘟热是由犬瘟热病毒引起的犬和肉食类动物的一种高度接触性传染病,病症复杂,致死率高.以双相热、白细胞减少、急性鼻卡他以及随后的支气管炎、卡他性肺炎、严重的胃肠炎和神经症状为特征.少数病例可出现鼻和足垫角质化过度.此病多发于寒冷季节,发病年龄主要集中在3~12月龄,传染性极强,发病率很高,死亡率高达80%,是对犬危害最大的疾病之一.     

Validation of endogenous reference genes for expression profiling of RAW264.7 cells infected with Mycobacterium avium subsp. paratuberculosis by quantitative PCR

Reference genes are frequently used to normalize between different biological samples the levels of mRNA measured using quantitative PCR (qPCR). The expression level of many commonly used reference genes has been shown to vary between tissues or cells, or following exposure to various treatments including infection with microbes. The selection of an appropriate reference gene for an individual experiment is therefore a crucial step in the process of accurately determining changes in gene expression. For this purpose, we analyzed the expression of nine commonly used reference genes in a murine macrophage cell line, RAW264.7, for their potential use in the analysis of differential gene expression by quantitative polymerase chain reaction (qPCR) following experimental infection with Mycobacterium avium subsp. paratuberculosis. Only one of nine putative reference genes tested, casc3a, was found to be suitable, and combinations of two or more reference genes were disadvantageous. Based on data from the study, we recommend an approach for selection of reference genes, conducting assays with technical replicates in duplicate rather than triplicate, determining decision-limit quality control criteria for technical replicates and assessing the significance of gene expression fold differences using DeltaDeltaC(t) based on knowledge of the variation in the reference gene.     

霉菌毒素危害奶牛生产

霉菌毒素是由霉菌或真菌产生的有毒有害物质。在土壤中,在植物上,包括符物、饲草和青贮饲料均可发现霉菌毒素。霉菌毒素可在农作物在大田收获时形成;在不适宜的贮存条件下。霉菌毒素也可继续在收获后的农作物上形成。较高的湿度通常有利于饲料中霉菌的生长和霉菌毒素的产生。温度是另一个重要的因素。高温和干旱环境下的农作物很容易遭受霉菌孢子的侵害．一旦条件允许．霉菌孢子可产生霉菌毒素。     

Thirteen-week Intravenous Toxicity Study of a Novel Humanized Anti-Human Death Receptor 5 Monoclonal Antibody, CS-1008, in Cynomolgus Monkeys

CS-1008, a humanized monoclonal antibody that is agonistic to human death receptor 5, was intravenously administered to cynomolgus monkeys twice a week for 13 weeks at 3 different dose levels (5, 15 and 42 mg/kg) in order to evaluate its potential toxicity. A control group received phosphate buffered saline containing 0.01% polysorbate 80. Each of the 4 groups consisted of 3 male and 3 female cynomolgus monkeys. No animal in any group died during the dosing period. No toxic changes in clinical signs, food consumption, body weight, electrocardiography, ophthalmology, urinalysis, hematology, blood chemistry, gross pathology, organ weights or histopathology were noted in any group during the dosing period. In the toxicokinetic analysis, the values for the maximum concentration of CS-1008 in plasma and the area under the curve generally increased with increasing dose. No clear differences in the toxicokinetic parameters or profiles were observed between the sexes. Development of anti-CS-1008 antibodies was not detected in any sample. The no-observed adverse-effect level (NOAEL) of CS-1008 in cynomolgus monkeys under the conditions of this study was concluded to be 42 mg/kg in both sexes, when administered intravenously twice a week for 13 weeks. This study supports the development of CS-1008 as a therapeutic biopharmaceutical.     

Detection of bovine herpesvirus 4 in CD11b+ leukocytes of experimentally infected rabbits

The presence and numbers of bovine herpesvirus 4 (BoHV-4) infected CD11b+ leukocytes were investigated during experimental infections of New Zealand White rabbits by Fluorescence Activated Cell Sorter (FACS) analysis. Peripheral blood leukocytes (PBL) were collected every second day, and the cells were stained with phycoerythrin-labelled CD11b-specific mouse monoclonal antibody and fluorescein-conjugated bovine herpesvirus 4-specific mouse monoclonal antibody. The numbers of double-stained cells from PBLs of the control and inoculated groups were measured and compared in FACSTREK analyser. Double-stained cells were detected in the virus-inoculated group on postinoculation days (PID) 2-5 and 9-12. The results indicated that CD11b+ PBLs were permissive for BoHV-4 infection, and are probably the main reservoir of the virus during the latent period. The data did not indicate production of infectious viral particles, but virus-specific proteins were expressed on the surface of CD11b+ cells. The two waves of double-stained cells gave similar results to the PCR assays from serum samples, which showed the presence of viral DNA in the serum on the same days when virus-infected CD11b cells were also present. Productive BoHV-4 infection of mast cells or undifferentiated leukocytes in the bone marrow and the antiviral immune response might be responsible for this periodic appearance of the virus in CD11b+ PBLs and in the serum. The paper provides evidence that CD11b+ PBLs are the main target cell populations in the blood for BoHV-4.     

Periparturient use of parenteral micronised procaine penicillin to reduce the risk of clinical mastitis in heifers after calving

Mastitis in primiparous heifers immediately postpartum can be both a significant welfare concern and a heavy economic loss. Interventions successfully researched include intramammary therapies. This study considered the clinical and practical effects of a parenteral approach to controlling clinical mastitis in heifers immediately postpartum. The objective of this field trial was to determine whether preventative treatment of heifers with a single parenteral treatment of 15 million iu micronised procaine penicillin within 12h after calving would reduce the incidence of clinical mastitis in early lactation as detected by farmers. All heifers (n=609) calving on three commercial dairy farms in New Zealand during the spring of 2006 were randomly allocated to either treatment or no treatment. Treatment (15 million iu micronised procaine penicillin) was given at the first milking following calving. All clinical mastitis was recorded. Treatment reduced the odds of having clinical mastitis within the first 7 days in milk by over half (Mantel-Haenszel adjusted OR=0.456; p=0.044); and reduced the odds of having mastitis within the first 100 days in milk by just under half (Mantel-Haenszel adjusted OR=0.518; p=0.027). Treatment had a significant effect on increasing the median days to clinical mastitis (p=0.019; beta=1.961, LCI 1.117, UCI 3.445). Preventative treatment of heifers immediately following calving with 15 million iu micronised procaine penicillin parenterally could be of benefit as part of a control programme aimed at reducing the incidence of clinical mastitis in heifers in their first lactation.