烟酸和烟酸铬对热应激奶牛产奶性能、血液生理生化指标的影响

选择2-4胎次泌乳中期的荷斯坦牛15头,配对分为3组,在7～9月进行60d的饲养试验,对照组使用基础日粮,两个试验组分别在基础日粮中添加烟酸800mg／kg和烟酸铬10nag／kg。结果表明：在持续高温天气下奶牛处于热应激状态。烟酸铬和烟酸均使奶牛体温上升幅度相对较小;烟酸铬还可以保持其呼吸率正常。二者均使产奶量下降幅度较小;烟酸铬组奶牛的乳脂率明显高于对照组和烟酸组（P〈0．05）;二者也使乳中挥发性脂肪酸比对照组明显提高（P〈0．05）,但对其他乳成分无显著影响（P〉0．05）。二者都能够维持奶牛血清T3、T4、COR、PRL水平的基本恒定;均显著降低了尿素氮和胆固醇水平（P〈0．05）。烟酸铬使奶牛的血液白细胞数和淋巴细胞百分比增加：烟酸仅使血液白细胞数增加。     

铬(Ⅲ)螯合物的制备及性质鉴定

铬是人和动物必需微量元素 ,铬的营养作用逐步被人们所揭示。一般认为铬以小分子络合物被肠粘膜吸收 ,添加铬的生物学效应表现为 :抗应激、提高瘦肉率、调节免疫、提高产仔性能等。目前在铬 (Ⅲ )的营养作用研究中 ,应用的铬络合物是多种多样的。我们制备了烟酸 -铬 (Ⅲ )(杂环配位体内络盐型 )、蛋氨酸 -铬 (Ⅲ ) (分子量较大的氨基酸配位体内络盐型 )、甘氨酸 -铬 (Ⅲ )(分子量最小的、溶解度较大的氨基酸配位体内络盐型 )。按溶解度排序 :烟酸铬 <蛋氨酸铬 <甘氨酸铬。1　试剂和仪器1 1　主要试剂和材料　ＤＬ -蛋氨酸、ＣｒＣｌ3·6Ｈ2…     

铬(Ⅲ)螯合物的制备及相关性质鉴定

本文报道了铬(Ⅲ)螯合物—烟酸铬(Ⅲ) ,蛋氨酸铬(Ⅲ)和甘氨酸铬(Ⅲ)的制备方法。通过对产物多方面的测定证实合成物均为铬(Ⅲ)的螯合物。同时对铬(Ⅲ)螯合物的结构、性质与动物营养作用的关系进行了探讨。     

烟酸和烟酸铬对断奶犊牛应激的影响

选用三月龄断奶荷斯坦犊牛30头,将其等分为三组,对照组为基础日粮,烟酸组和烟酸铬组分别在基础日粮中添加400 mg/kg的烟酸和6.4 mg/kg的烟酸铬。结果表明:烟酸和烟酸铬在前10 d对犊牛的增重影响不明显(P〉0.05);20~30 d,烟酸组和烟酸铬组的平均日增重比对照组分别提高5%和27.6%;30~40 d,烟酸组和烟酸铬组的平均日增重比对照组分别提高12.8%和18.11%;而最后一个阶段,烟酸组和烟酸铬组的平均日增重比对照组分别提高8.9%和7.45%。试验期间,烟酸铬组与对照组相比提高T3、T4、生长激素、胰高血糖素水平分别为25.68%(P〈0.05)、17.31%、6.73%、9.03%;烟酸组与对照组相比提高T3、T4水平分别为11.5%、12.7%。     

不同水平烟酸铬对热应激状态下水牛泌乳性能、抗氧化性能和瘤胃微生物多样性的影响

本试验旨在研究不同添加水平烟酸铬对热应激状态下水牛泌乳性能、抗氧化性能和微生物多样性的影响。试验选取体重、日龄、胎次和产奶量相近，泌乳中期的健康尼里-拉菲水牛20头。采用单因素随机区组设计，将试验牛分为4组（Ⅰ、Ⅱ、Ⅲ、Ⅳ组），每组5个重复。Ⅰ组饲喂基础日粮，Ⅱ、Ⅲ、Ⅳ组在基础日粮中分别添加1.5、3.0和4.5 mg/（d·头）烟酸铬。试验预饲期1周，试验期4周。试验结果表明，热应激条件下，①日粮中添加不同水平的烟酸铬对干物质采食量的影响差异不显著（P>0.05），试验组中性洗涤纤维（NDF）和酸性洗涤纤维（ADF）的表观消化率均有不同程度上升；②日粮中烟酸铬添加水平对瘤胃pH、以及乙酸、丙酸、丁酸等挥发性脂肪酸无显著影响（P>0.05）；③日粮添加3.0 mg/（d·头）烟酸铬显著提高了水牛的产奶量（P<0.05）；各组间乳蛋白率、乳脂率、乳总固形物和非脂固形物差异不显著（P>0.05）；④水牛血清丙二醛（MDA）含量、谷胱甘肽过氧化物酶（GSH-Px）和过氧化氢酶（CAT）活性在试验组与对照组间无显著差异（P>0.05）；与对照组相比，3.0 mg/（d·头）烟酸铬组的三碘甲状腺原氨酸（T3）和甲状腺素（T4）浓度显著增加（P<0.05）；⑤与对照组相比，试验组水牛长链乳脂不饱和脂肪酸的含量有所提高；⑥在门水平上，各组水牛的优势菌群均为拟杆菌门（Bacteroidetes）、厚壁菌门（Firmicutes）和变形菌门（Proteobacteria），样本整体呈现出较丰富的多样性。日粮添加3.0 mg/（d·头）烟酸铬能改善水牛泌乳性能及抗氧化性能，效果优于其他组。     

用烟酸铬饲养肉鸭的试验报告

烟酸铬作为饲料添加剂具有强化胰岛素功能、促进糖代谢和蛋白质代谢、提高抗应激能力，并能显著提高瘦肉率、产蛋率、产奶量。另外还能促进生长，降低饲料消耗。本试验目的是验证烟酸铬在肉鸭饲养中的试验效果。 一．材料与方法 １有机铬来源 本试验所用的烟酸复合物由成都力源农牧科研所提供，铬－烟酸复合物过６０目筛，经多级混合而拌入饲料中。 ２试验动物与饲粮 选择１日龄樱桃谷商品代肉鸭４００只，随机分为５组，每组８０只。各组鸭的饲粮（表１）。中添加不同铬量（０、１００、２００、４见和８００ｐｐｂ）的铬－烟复合物。 ３．…     

新型饲料添加剂烟酸铬

烟酸铬(Chromium nicolinale)是烟酸和三价铬离子形成的螯合物。动物营养学家认为,铬(Ⅲ)是动物营养的必需成分,并对此进行了深入的研究。烟酸是动物必需的B族维生素,动物若得不到足够的烟酸可导致采食量和饲料转化率降低,生产性能明显下降。近几年来,铬及有机铬对动物生长性能的影响是目前国内外动物营养学中一个比较热门的课题,对其在动物体内的生理、生化     

烟酸和烟酸铬对热应激奶牛产奶性能、血液生理生化指标的影响

选择2~4胎次泌乳中期的荷斯坦牛15头,配对分为3组,在7~9月进行60d的饲养试验,对照组使用基础日粮,两个试验组分别在基础日粮中添加烟酸800 mg/kg和烟酸铬10 mg/kg。结果表明:在持续高温天气下奶牛处于热应激状态。烟酸铬和烟酸均使奶牛体温上升幅度相对较小;烟酸铬还可以保持其呼吸率正常。二者均使产奶量下降幅度较小;烟酸铬组奶牛的乳脂率明显高于对照组和烟酸组(P<0.05);二者也使乳中挥发性脂肪酸比对照组明显提高(P<0.05),但对其他乳成分无显著影响(P>0.05)。二者都能够维持奶牛血清T3、T4、COR、PRL水平的基本恒定;均显著降低了尿素氮和胆固醇水平(P<0.05)。烟酸铬使奶牛的血液白细胞数和淋巴细胞百分比增加;烟酸仅使血液白细胞数增加。     

烟酸铬在畜禽生产中的应用

烟酸铬是烟酸与三价铬离子形成的螯合物,具有促进动物生长、增强免疫功能、提高胴体品质和改善繁殖性能等营养生理作用。本文主要介绍了烟酸铬在畜禽生产中的营养作用。     

烟酸铬对西门塔尔牛精料瘤胃降解率的影响

试验选用4头平均体重500±20kg,年龄4岁,装有永久性瘤胃瘘管的西门塔尔牛阉牛,采用4×4拉丁方试验设计,以混合精料和风干玉米秸秆为基础日粮,研究1.3倍维持水平下,日粮添加烟酸铬（0mg/d、40mg/d、80mg/d、120mg/d）对精料瘤胃降解率的影响。结果表明：日粮添加烟酸铬组DM有效降解率与对照组差异不显著（P〉0.05）,添加80mg/d烟酸铬组精料OM有效降解率、CP瘤胃有效降解率较对照组显著提高（P〈0.05）。本试验结果表明：日粮添加烟酸铬的适宜添加水平为80mg/d。     

螺虫乙酯及其四种代谢产物在柑橘中的消解代谢和残留规律研究

为对螺虫乙酯及其四种代谢产物的消解残留和代谢行为做出科学评价。利用液相色谱串联质谱研究了一年三地螺虫乙酯及其四种代谢产物在柑橘中的消解动态、最终残留和代谢行为。螺虫乙酯及其代谢产物在柑橘中的添加回收率为71.4%~107.1%。相对标准偏差在0.5%~7.28% 之间,最低检出浓度均为0.02mg/kg,降解半衰期为1.74~5.83d,螺虫乙酯-烯醇、螺虫乙酯-酮羟基、螺虫乙酯-烯醇-吡喃葡萄糖在螺虫乙酯代谢行为中均有不同程度检出。按照推荐剂量的1.5倍施药3次,21 d后柑橘中螺虫乙酯及其代谢物残留量均小于MRL值(1 mg.kg -1),收获的柑橘可以食用。应注重代谢产物对生态环境的影响。     

茧丝纤度曲线的解析模型及其在模拟缫丝中的应用

建立了一种茧丝纤度曲线的统计解析模型 ,分析其用于模拟茧丝时茧丝纤度曲线的统计特性 ,证明这是一种有利于控制模拟生成的茧丝纤度特性的方法。通过计算机模拟试验讨论其在茧丝纤度曲线模拟及缫丝工程模拟中的应用。     

磺胺喹噁啉偶联物的合成与鉴定

磺胺喹噁啉(sulfaquinoxaline,SQ)经重氮化后,与牛血清白蛋白在碱性条件下发生重氮化偶联反应生成偶联物。偶联物经红外光谱、十二烷基磺酸钠-聚丙烯酰胺凝胶电泳及基质辅助激光解吸电离-飞行时间-质谱(MALDI-TOF-MS)鉴定,确定偶联成功。对上述几种人工抗原鉴定方法进行了简单比较,认为MALDI-TOF-MS是鉴定偶联物的最佳方法,并且为磺胺喹噁啉的酶联免疫分析奠定了基础。     

Isolation and characterization of the immunoglobin of pike (Esox lucius L.)

The purification of the immunoglobul in from pike serum and its physicochemical characterization is presented. The immunoglobul in was prepared by means of gel filtration and ion exchange chromatography. Measurements in the analytical ultracentrifuge showed a sedimentation constant of 15.0 S. A molecular weight of 650.000 was calculated. The immunoglobulin was composed of heavy and light chains of molecular weights 60.000 and 22.500, respectively. It is likely that the immunoglobulin of pike is composed of 8 heavy and 8 light chains and possesses a tetrameric structure. The heavy chains contain 9.2% sugars and amino sugars. The amino acid composition of the chains is similar to that of other fish immunoglobulins.     

Plasma creatinine in dogs: intra- and inter-laboratory variation in 10 European veterinary laboratories

Background

There is substantial variation in reported reference intervals for canine plasma creatinine among veterinary laboratories, thereby influencing the clinical assessment of analytical results. The aims of the study was to determine the inter- and intra-laboratory variation in plasma creatinine among 10 veterinary laboratories, and to compare results from each laboratory with the upper limit of its reference interval.

Methods

Samples were collected from 10 healthy dogs, 10 dogs with expected intermediate plasma creatinine concentrations, and 10 dogs with azotemia. Overlap was observed for the first two groups. The 30 samples were divided into 3 batches and shipped in random order by postal delivery for plasma creatinine determination. Statistical testing was performed in accordance with ISO standard methodology.

Results

Inter- and intra-laboratory variation was clinically acceptable as plasma creatinine values for most samples were usually of the same magnitude. A few extreme outliers caused three laboratories to fail statistical testing for consistency. Laboratory sample means above or below the overall sample mean, did not unequivocally reflect high or low reference intervals in that laboratory.

Conclusions

In spite of close analytical results, further standardization among laboratories is warranted. The discrepant reference intervals seem to largely reflect different populations used in establishing the reference intervals, rather than analytical variation due to different laboratory methods.     

检测鱼肉新鲜度的酶生物传感器的研制

为探索检测鱼肉新鲜度的快速、灵敏、方便的检测方法,本实验将生物化学技术和传感技术相结合,研制出了通过检测鱼肉中次黄嘌呤含量而间接检测鱼肉新鲜度的酶传感器。结果表明,所研制的仪器及相应的检测方法稳定性、重现性良好,目前最低检测限可达0.15mg/L,检测时间在5分钟以内,检测成本每个样品5元,而且该传感器成本低廉,体积小、携带方便、操作简单,完全能满足现场检测的需要。     

Internal quality control of a turbidimetric immunoassay for canine serum C-reactive protein based on pooled patient samples

BACKGROUND: Optimized internal quality control (IQC) procedures are important to ensure that only results without medically important errors are used for medical decision-making and to ensure that unnecessary rejection of valid analytical runs is avoided. Additionally, estimates of the analytical performance can be derived from IQC data. In the absence of available species-specific standards of a compound, the use of alternative control materials based on patient samples is a possibility, although investigations on the suitability of this approach are needed. OBJECTIVES: The objective of the study was to plan and implement a simple IQC procedure with control material based on pooled canine serum samples for a turbidimetric immunoassay (TIA) for the determination of human C-reactive protein (CRP) that recently was validated for the determination of canine serum CRP, and to assess the clinical analytical performance of the assay. METHODS: Proposed guidelines for the planning and implementation of IQC procedures were followed by using 2 control materials. Quality requirements of the assay were defined objectively by means of available data on biological variation, and goals for IQC performance were defined according to recommendations (probability of error detection [P(ed)] >.90 and of false rejection [P(fr)] <.05). Analytical performance was evaluated by means of medical decision charts. RESULTS: The control rule of 1(2.5s) (ie, rejection of the analytical run if at least 1 of 2 control materials deviates from the mean by more than 2.5 SD) fulfilled the criteria of predicted IQC performance (P(ed) =.94-1.00, P(fr) =.03). The IQC method was successfully implemented over a 14-week period. The observed coefficient of variation in the period of monitoring was 3.8% (low) and 2.9% (high), which equals excellent analytical performance. CONCLUSIONS: It was possible to plan and implement a simple IQC procedure for the CRP-TIA with control materials based on canine serum samples that fulfilled the criteria of high error detection and low false rejection of valid analytical runs. The assay showed excellent long-term analytical performance over a 14-week period.     

PCR-SSCP技术在动物育种中的研究进展

PCR—SSCP技术是新近发展起来的一种分子生物学分析方法，由于其广泛和潜在的应用价值，已被广泛应用于医学和其他生命科学的研究中。本文介绍了PCR—SSCP技术的发展、特点及其在动物遗传育种研究中的应用和发展前景。     

Spatial epidemiological approaches to inform leptospirosis surveillance and control: A systematic review and critical appraisal of methods

Leptospirosis is a global zoonotic disease that the transmission is driven by complex geographical and temporal variation in demographics, animal hosts and socioecological factors. This results in complex challenges for the identification of high‐risk areas. Spatial and temporal epidemiological tools could be used to support leptospirosis control programs, but the adequacy of its application has not been evaluated. We searched literature in six databases including PubMed, Web of Science, EMBASE, Scopus, SciELO and Zoological Record to systematically review and critically assess the use of spatial and temporal analytical tools for leptospirosis and to provide general framework for its application in future studies. We reviewed 115 articles published between 1930 and October 2018 from 41 different countries. Of these, 65 (56.52%) articles were on human leptospirosis, 39 (33.91%) on animal leptospirosis and 11 (9.5%) used data from both human and animal leptospirosis. Spatial analytical (n = 106) tools were used to describe the distribution of incidence/prevalence at various geographical scales (96.5%) and to explored spatial patterns to detect clustering and hot spots (33%). A total of 51 studies modelled the relationships of various variables on the risk of human (n = 31), animal (n = 17) and both human and animal infection (n = 3). Among those modelling studies, few studies had generated spatially structured models and predictive maps of human (n = 2/31) and animal leptospirosis (n = 1/17). In addition, nine studies applied time‐series analytical tools to predict leptospirosis incidence. Spatial and temporal analytical tools have been greatly utilized to improve our understanding on leptospirosis epidemiology. Yet the quality of the epidemiological data, the selection of covariates and spatial analytical techniques should be carefully considered in future studies to improve usefulness of evidence as tools to support leptospirosis control. A general framework for the application of spatial analytical tools for leptospirosis was proposed.     

Variability among sources and laboratories in nutrient analyses of corn and soybean meal. NCR-42 Committee on Swine Nutrition. North Central Regional-42

A cooperative research study involving members of a regional committee (North Central Regional Committee on Swine Nutrition [NCR-42]) was conducted to assess the variability in nutrient composition (DM, CP, Ca, P, Se, and amino acids) of corn and soybean meal from 16 sources (15 states, mostly in the Midwest) and to assess the analytical variability in nutrient assays among 22 laboratories (labs; 16 experiment station labs and six commercial labs). Corn samples were obtained from each participating station's feed mill during a 3-yr period (1989, 1990, and 1992), as were soybean meal samples during a 2-yr period (1989 and 1990). Both regular soybean meal (with hulls) and dehulled soybean meal were represented in the study. Samples were analyzed for DM and CP by all 22 labs, for Ca and P by 15 labs, for amino acids by 10 labs, and for Se by 6 labs. Each lab used its own analytical procedures. Samples of corn and soybean meal varied in their nutrient composition depending on the area of origin. The greatest variation among sources was in Se concentration, ranging from .02 to .29 mg/kg in corn and .08 to .95 mg/kg in soybean meal. Crude protein and lysine in corn were positively correlated, but the regression coefficient was low (r2 = .49). The relationship between CP and lysine for the two soybean meals combined was considerably stronger (r2 = .81). Lysine in corn increased by .018 percentage point and lysine in soybean meal (regular and dehulled combined) increased by .063 percentage point for each 1 percentage point increase in CP. Except for CP and Se, the analytical variability among labs was as great as, and in some cases greater than, the variability in nutrient composition among sources of corn and soybean meal. Within-lab analytical variability tended to be less than among-lab variability. Some labs performed certain analyses with considerably less variability and more accuracy than others.