肉鸡生产全过程控制与产品质量可追溯技术平台

<正>近年来,国内外发生了许多食品安全事件,如欧洲的"二恶英和疯牛病"事件,美国的"毒菠菜"事件,日、韩、越、中等国家暴发的禽流感疫情,以及近期我国发生的奶制品"三聚氰胺"事件,这些事件均表明世界食品安全形势日趋严峻。能否在食品安全事件未发生前或发生初期就做出警报?能否在事件发生后事故处理时能落实并追究到具体的相关责任单位     

家禽生长促进剂天然替代物

<正>自欧洲禁用抗生素生长促进剂(AGPs)以来,市场上出现了各种各样的AGPs替代品。这些产品的目的必须确保其效果至少不低于所替代的产品,而且还必须使动物的生理状态与环境相协调。     

内蒙古玉米秸秆还田土壤细菌多样性特征

通过内蒙古半干旱冷凉地区玉米秸秆还田定位试验,结合常规分析手段和变性梯度凝胶电泳(DGGE)技术初步研究了玉米秸秆深翻还田后土壤有机质、纤维素酶活性及土壤细菌多样性变化。结果表明,随着玉米生育期的推进,土壤有机质含量呈先增加后下降趋势,拔节期和大喇叭口期含量较高。玉米秸秆深翻还田一年(SF-Ⅰ)和连续两年玉米秸秆深翻还田(SF-Ⅱ)0～20 cm土层有机质含量除了播种期差异显著外,其余生育期均无显著差异,但均与常规旋耕秸秆不还田(CK)有显著差异;20～40 cm土层SF-Ⅰ、SF-Ⅱ和CK有机质含量除了播种期差异显著外,其余生育期均无显著差异;玉米成熟期土壤有机质含量为SF-ⅡSF-ⅠCK;随着土层的下移土壤有机质含量呈逐渐降低的趋势。秸秆深翻还田后土壤纤维素酶活性明显增强,表现为SF-ⅡSF-ⅠCK;拔节期和大喇叭口期土壤纤维素酶活性增幅较高,与CK差异达到显著水平;纤维素酶活性随土层的下移逐渐下降,0～20 cm土层中,播种期至大喇叭口期秸秆还田土壤纤维素酶活性与CK间差异显著,其余时期无显著差异;20～40 cm土层中,仅播种期秸秆还田土壤纤维素酶活性与CK间差异显著。16S rDNA-PCR-DGGE分析可知,秸秆还田后拔节期至灌浆期土壤细菌群落发生较大的变化,拔节期变化最大。SF-Ⅱ、SF-Ⅰ、CK土壤菌属不同,细菌多样性指数SF-ⅡSF-ⅠCK;秸秆深翻还田增加了土壤细菌多样性,尤其是土壤中纤维素分解菌和有机污染物降解菌群。半干旱冷凉地区两年秸秆还田的土壤细菌多样性比一年秸秆还田的效果更为明显。     

Clinical evaluation of protein electrophoresis of cerebral spinal fluid

Protein fractions of cerebral spinal fluid samples were analyzed in an effort to find a reliable, minimally invasive and cost effective method of diagnosing cervical vertebral myelopathy. There were six separate protein fractions analyzed by electrophoresis. In this study we specifically looked for a post beta spike in horses with spinal cord compression. There was no correlation in our study between horses with a post beta spike and CVM as diagnosed by a myelogram.     

Spatial structure and inter-firm networks of technical and information producer services in Seoul,Korea

A spatial and sectoral reorganisation of producer services has begun to change the urban structure of Seoul. In addition to the existing centre of the CBD, two areas, Kangnam and Yongdeungpo, have emerged as the new centres of producer services in Seoul resulting from relocations from the CBD and the location of firm start-ups and spin-offs, so creating a multi-centred structure. There is a difference between the centres related to the fact that Kangnam is specialised in advanced services and has strong local networks among service firms, firms in Yongdeungpo have strong forward linkages to nearby manufacturing firms and to larger producer service firms, while firms in the CBD are relatively older and have much more intensive overseas ties. This outcome illustrates that shifts in the organisation of producer services in favour of outsourcing have been felt in shifts in spatial patterns. These new structures illustrate that producer service location and operation have a powerful influence upon the pattern of development in Seoul.     

不同年限玉米秸秆还田对土壤微生物多样性的影响

秸秆还田是培肥地力、改良土壤的重要措施。内蒙古高原向松辽平原过渡地带春玉米区,玉米长期连作导致了耕层变薄、土壤次生盐渍化等土壤退化问题。采用田间定位试验的方法,研究连续多年(8、5、2年)秸秆旋耕还田条件下对土壤微生物的影响。结果表明,秸秆还田土壤中最丰富的细菌类型为变形菌门(Proteobac-teria),其次为放线菌门(Actinobacteria)、芽单胞菌门(Gemmatimonadetes)、拟杆菌门(Bacteroidetes);真菌类型为子囊菌门(Ascomycota)和担子菌门(Basidiomycota)。随着秸秆还田年限的增加,变形菌门和酸杆菌门(Acidobacteria)相对丰度增加、放线菌门相对丰度下降,拟杆菌门相对丰度较稳定;子囊菌门、担子菌门、接合菌门(Zygomycota)相对丰度先下降后上升,而球囊菌门(Glomeromycota)和壶菌门(Chytridiomycota)相对丰度变化规律相反;属水平上Sphingomonas、Lysobacter、Hannaella相对丰度先上升后下降,而Leptosphaeria和Mono-dictys相对丰度变化规律相反;Pseudarthrobacter、Fusarium相对丰度下降,Gaiella相对丰度较稳定;Guehomyces相对丰度增加;并且细菌和真菌相对丰度拐点均出现在秸秆还田5年后。随着秸秆还田年限的增加,土壤细菌和真菌多样性均有所降低;秸秆还田与秸秆不还田土壤的差异物种有Aquicella、Fusicolla和Spizellomyces;由此可推测,秸秆还田增加土壤氮和钾含量,减少病害;试验区连续多年的玉米秸秆还田改变了土壤微生物群落组成,玉米秸秆连续还田5年后土壤微生物多样性有下降趋势。     

Hydrogen radicals, nitrogen radicals, and the production of O3 in the upper troposphere

The concentrations of the hydrogen radicals OH and HO2 in the middle and upper troposphere were measured simultaneously with those of NO, O3, CO, H2O, CH4, non-methane hydrocarbons, and with the ultraviolet and visible radiation field. The data allow a direct examination of the processes that produce O3 in this region of the atmosphere. Comparison of the measured concentrations of OH and HO2 with calculations based on their production from water vapor, ozone, and methane demonstrate that these sources are insufficient to explain the observed radical concentrations in the upper troposphere. The photolysis of carbonyl and peroxide compounds transported to this region from the lower troposphere may provide the source of HOx required to sustain the measured abundances of these radical species. The mechanism by which NO affects the production of O3 is also illustrated by the measurements. In the upper tropospheric air masses sampled, the production rate for ozone (determined from the measured concentrations of HO2 and NO) is calculated to be about 1 part per billion by volume each day. This production rate is faster than previously thought and implies that anthropogenic activities that add NO to the upper troposphere, such as biomass burning and aviation, will lead to production of more O3 than expected.     

Equine bronchoalveolar lavage cytology: survey of Thoroughbred racehorses in training

SUMMARY Sixty-two Thoroughbred horses aged between 1 and 7 years in training in Sydney had bronchoalveolar lavage (BAL) samples collected for cytological examination. All horses, except the yearlings and those with a cough, had raced at the time of the examination and the trainers reported satisfactory performance. Free erythrocytes were found In 73% of samples and haemoslderophages In 90% of the samples, Indicating Immediate or past occurrences of exercise-Induced pulmonary haemorrhage (EIPH). Bronchoalveolar fluid from the yearlings contained significantly less (P / 0.05) erythrocytes and haemosiderophages than samples from horses In other age groups. In the older horses, there was also more haemosiderln within the macrophages. No differences In BAL cytology could be attributed to gender, and there was no relationship between BAL cytology and racing performance. The main cytological findings were (mean ± sd): total nucleated cells - 832 ± 578/μL with the main cell types being: macrophages - 59 ± 10% (haemosiderophages - 20 ± 24%); neutrophlls - 9 ± 6%; lymphocytes - 31 ± 9%. The erythrocyte count was 10.3 ± 17.7% of the total cell count. Horses with chronic coughing had a higher proportion of macrophages and a lower proportion of lymphocytes in the leucocytes obtained from BAL. There was a higher occurrence of EIPH detected In BAL findings than that previously reported when endoscopic examination has been used to diagnose EIPH. The occurrence and severity of EIPH as Indicated by the BAL findings was found to be related to exercise Intensity. The cytological findings were similar to those reported in horses in the northern hemisphere. We conclude that BAL cytology may be useful In the diagnosis of various lower respiratory tract disorders and that exercise-induced pulmonary haemorrhage occurs In virtually all horses In race training.     

Responses in milk production to the control of gastrointestinal nematode and paramphistome parasites in dairy cattle

Objective To determine the effect of treating naturally acquired gastrointestinal nematode and paramphistome infections on milk production in dairy cattle.
Design A field trial.
Animals One thousand two hundred and thirty nine dairy cows.
Procedure Cows were either not treated or treated with 4.5 mg/kg oxfendazole, 16.6 mg/kg oxyclozanide or 4.5 mg/kg oxfendazole and 16.6 mg/kg oxyclozanide in March, May and August.
Results A significant increase in milk production, averaging 0.4 L (SE 0.2) per day, was seen when dairy cows infected with gastrointestinal nematodes and paramphistomes were treated with oxfendazole or oxfendazole and oxyclozanide in March, May and August. Cows treated with oxyclozanide alone at these times produced no more milk than untreated cows.
Faecal egg counts confirmed that oxyclozanide treatment reduced paramphistome populations and oxfendazole treatment reduced nematode populations in cows over the 7-month monitoring period.
Conclusion When dairy cows infested with gastrointestinal nematodes and paramphistomes were treated with oxfendazole alone or oxfendazole and oxyclozanide in March, May and August milk production increased.