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1.
We carried out a field evaluation of the MM3-SERO ELISA for the diagnosis of Fasciola hepatica infection, by analysing serum and milk samples from individual cows and samples from bulk milk tanks. The diagnostic performance of the assay was assessed with serum samples from all 257 cows in eight fluke-free herds, and 240 cows with natural fasciolosis (diagnosed in vivo and/or post-mortem). Assay performance for individual milk samples was determined by analysis of paired serum and milk samples from 947 lactating cows from 33 F. hepatica-infected farms. The diagnostic usefulness of the assay for bulk tank milk was evaluated by analysis of bulk milk from infected (33) and non-infected (35) farms. For serum samples, the sensitivity, specificity and diagnostic accuracy of the assay were respectively 99.2% (95% CI: 97.0%–99.9%), 100% (95% CI: 98.6%–100%) and 0.997 (95% CI: 0.987–1.000). The only two infected animals in which serum antibodies were not detected had very low parasitic burdens (with only 2 and 3 flukes observed). The performance of the MM3 SERO ELISA for individual milk samples was similar to that for serum samples, and the stepwise linear regression revealed a strong correlation between the results for the milk samples and the serum samples (R2 = 0.84; p < 0.001). The agreement between results obtained with pairs of serum and milk samples was very high: there was matching classification in 96% (910/947) of paired samples (kappa = 0.92; p < 0.001). Individual milk samples may therefore be used, instead of serum samples, in the MM3-SERO ELISA, for reliable detection of seropositive cows. Testing bulk tank milk samples enabled detection of infected herds, even when the within-herd prevalence of infection was as low as 12%. We conclude that the MM3-SERO ELISA is a sensitive and highly specific test for serodiagnosis of bovine fasciolosis, and can be used with individual samples of either serum or milk. Use of the assay with bulk milk samples enables estimation of the within-herd prevalence of infection.  相似文献   

2.
In France, numerous Protected Designation of Origin (PDO) cheese value chains have revised their specifications to address environmental protection, particularly at the farm level. In this stage, it is nevertheless impossible to state whether the proposed modifications may ensure the sustainability of environmental protection as no environmental sustainability diagnostic has been conducted. The aim of this study is to construct an assessment method for the Cantal PDO farms.A multi-criteria assessment approach was implemented in the following 5 steps: definition of the framework of the study, determination of the principles and criteria, definition of the indicators, aggregation of all elements of the assessment, and finally, test of the assessment method on farms. Focus groups meetings were organised for the first four steps. The panel discussions were based on data obtained from both the literature and surveys of stakeholders operating in the value chain and within the territory.The obtained assessment method comprises 4 principles characterised by 33 indicators. The most important principle (45%), management of grassland resources, is a key economic and environmental point of the studied farms. It reflects the necessary intensive use of grass by the animals in the PDO farms. Few existing methods addressed this principle that required the design of several new indicators. The second principle, impact of agricultural practices (25%), is often included in environmental sustainability assessment methods The adopted indicators are, thus, drawn from existing methods and adapted to the context of the farms studied. The management of the farm buildings and the landscape principle (18%) is often considered in social sustainability. Its role in environmental sustainability can be explained by its strong link with the image of PDO products. Primarily drawn from the literature, the used indicators have been extended to make the assessment method as objective as possible. Finally, the management of local, energy and water resources principle has the lowest weighting (12%). This can be explained by the limited number of indicators.This assessment method was constructed for the Cantal PDO farms by considering their environment and particularities. In consequence, the stakeholders have taken ownership of it. It could be used by other ruminant systems based on grassland. The development of numerous indicators enhanced the pool of existing indicators. This assessment method was sensitive and allowed for the discrimination between farms.  相似文献   

3.
Vito Vetrugno 《Biometals》2004,17(3):353-356
Bovine Spongiform Encephalopathy (BSE) belongs to Transmissible Spongiform Encephalopathies (TSEs) or Prion diseases. BSE is a feed borne infection of cattle. Epidemiological and laboratory data suggest that the BSE infectious agent is responsible for the variant form of Creutzfeldt-Jakob Disease (vCJD) and that the oral route is the most plausible way of infection. Therefore there is concern that the BSE agent can be transmitted to humans by biological materials (i.e. meat products, blood, milk) from susceptible BSE animal species (mostly cows but possibly, sheep and goats). Lactoferrin (LF) can be produced by purification from large volumes of cow's milk or whey. Therefore, a potential BSE risk for milk and milk products needs to be evaluated by risk assessment. The Committee for proprietary Medicinal Products--CPMP of the European Commission and the WHO have categorized risk tissues from TSE susceptible ruminant species in different classes in relation to the BSE risk for medicinal products. Milk, colostrum, and tissues of the mammary gland have been classified in the category of no detectable infectivity. A secondary contamination of milk can be virtually excluded (i.e. milk is taken from living animals). In the light of current scientific knowledge and irrespective of the geographical origin, milk and milk derivatives (e.g. lactoferrin, lactose) are unlikely to present any risk of TSE contamination provided that milk is sourced from healthy animals in the same conditions as milk collected from human consumption. So the risk of milk and milk derivatives in relation to BSE is negligible.  相似文献   

4.
The effects of adding lysine and/or methionine to a ration of calculated deficiency in these amino acids of 10% and 20%, respectively, were studied in 24 Brown Swiss cows. The mixed rations (27% grass silage, 19% maize silage, 5% hay and 49% concentrate on DM basis) contained 14.5% CP on average. Lysine supply was selectively elevated by adding fish meal in exchange for other concentrate ingredients. Methionine was supplied in a rumen‐protected form. Milk protein content was elevated whereas fat amount decreased by adding both amino acids. Lactose content increased without additional lysine from fish meal. Live weight, milk yield, milk fat content and protein amount remained unaffected by any variation of amino acids supply. Also nutrient digestibility and nitrogen balance were not changed by the treatments. Blood plasma concentrations confirmed the assumed variation in metabolic lysine and, less clear, methionine supply. Effects on plasma concentrations of other amino acids were relatively small. Most plasma hormones and enzymes, and metabolites in plasma, urine and milk did not respond to the variation in amino acid supply. Lysine addition via fish meal increased aspartate amino transferase and decreased urinary allantoin concentration. Additional methionine elevated plasma ornithine. Overall lysine and methionine appear to have been only marginally deficient in the unsupplemented ration fed for 3 weeks despite the deficiency of 10% to 20% as calculated by the I.N.R.A. method.  相似文献   

5.
The objective of this study was to investigate the influence of a niacin supplementation to three diets with different forage-to-concentrate ratios on blood and milk parameters. Seven midlactation (102 ± 18 days in milk) and three dry cows of the Holstein-Friesian breed, equipped with cannulas in the dorsal sac of the rumen and proximal duodenum, were used. On a dry matter basis the rations applied consisted of either ? concentrate and ? forage (LC), ½ concentrate and ½ forage (MC), or ? concentrate and ? forage (HC). They were fed for one period without and in the following with a supplementation of 6 g niacin (nicotinic acid) per cow per day. The basal niacin content was 35.0 mg/kg for LC, 34.6 mg/kg for MC and 34.4 mg/kg for the HC diets on a dry matter basis. Blood was sampled before, then three and six hours after first morning feeding from the vena jugularis externa. Milk samples were obtained on two days. Niacin feeding enhanced concentrations of glucose and urea in serum (p < 0.05). No effect of supplemental niacin was seen on serum non-esterified fatty acids or ß-hydroxybutyrate concentrations. Increasing the proportion of concentrate and niacin supplementation enhanced serum nicotinamide concentration (p < 0.01). Nicotinamide concentrations or amounts excreted via milk were influenced by forage-to-concentrate ratio (p < 0.05), but not by niacin supplementation. Milk fat composition showed an effect of additional niacin, as the proportion of oleic acid increased in milk of niacin supplemented cows (p = 0.04). For all parameters analysed, no significant interaction between forage-to-concentrate ratio and niacin supplementation was found.  相似文献   

6.
Aims: A microbiological bioassay using Geoacillus stearothermophilus was optimized to detect betalactams at concentrations near to the Maximum Residue Limits (MRLs), with low cross‐specificity for tetracycline. Methods and Results: A factorial design (3 × 4) was used to evaluate the effects of concentration of spores (2·0 × 106, 4·0 × 106 and 8·0 × 106 spores ml?1) and incubation time (3·0, 3·5, 4·0 and 4·5 h) on the response of the bioassay. Then, desirability function to raise the detection capabilities (CCβ) of tetracyclines and increase sensitivity to betalactams was implemented. Significant effects of Log[S] and incubation time [It] on the CCβ of betalactams and tetracyclines were observed. Finally, high value of global desirability (D = 0·853), adequate betalactams CCβ (3·8 μg l?1 of penicillin ‘G’, 27 μg l?1 of oxacillin, 8·1 μg l?1 of ampicillin, 48 μg l?1 of cloxacillin) and high tetracyclines CCβ (5260 μg l?1 chlortetracycline, 1550 μg l?1 of oxytetracycline, 1070 μg l?1 of tetracycline) were calculated. Conclusions: The application of chemometric tools allows the optimization of a bioassay that detects betalactam residues in milk. The more robust conditions have been achieved in Log[S] = 6·30 and [It] = 4·20 h. Significance and Impact of the Study: The logistic regression model and the desirability function are adequate chemometric techniques to improve the properties of the methods, because it is possible to increase sensitivity and decrease cross‐specificity simultaneously.  相似文献   

7.
Aim: To evaluate the rpoB gene as an alternative to the V3 gene for the identification of bacterial species in milk and milk products. Methods and Results: DNA obtained from different bacterial species strains was amplified by PCR using rpoB primers. PCR products of each bacterial species were then separated on a DGGE gel. The molecular fingerprints of the bacterial species tested were integrated into a database. The DGGE analysis shows a single band for the rpoB gene amplicons per each bacterial species. Comparison of electrophoretic profiles obtained from V3 16S rDNA amplification with those from this study obtained with rpoB showed that for some bacterial species that co‐migrated after amplification of the V3 region, distinct bands were observed on the gel with the amplification products of the rpoB region. Conclusions: The results obtained in this study show the discriminatory power of the rpoB gene, indicating that it can be used as an alternative to the V3 16S rRNA gene for the identification of bacterial species in milk and milk products. Significance and Impact of the Study: PCR‐DGGE targeting the rpoB gene is a way of discriminating the bacterial species that co‐migrated with the amplification of the V3 gene and so avoids the sequencing of the co‐migrating bands.  相似文献   

8.
A reversed-phase high-performance liquid chromatography with ultraviolet (UV) detection was developed that can determine 11 benzimidazole (BZDs) and 10 metabolites of albendazole, fenbendazole and mebendazole in bovine milk. Samples were extracted with acetonitrile and purified by mixed-mode cation exchange (MCX) solid phase extraction cartridges. LC separations were performed on a C18 column with gradient elution using acetonitrile and ammonium acetate solution. The UV-detection was set at 292 nm. The method is very sensitive to each analyte with limits of quantification (LOQs) of lower than 10 μg kg−1. The recoveries of the BZDs and their metabolites spiked in milk were more than 78% with between-day relative standard deviation values less than 16% at the concentration of 10, 50 and 100 μg kg−1. The method developed has been successfully applied to monitoring real samples containing BZDs, which demonstrated that it is a simple, fast and robust method, and could be used as a regulatory toll to determine the residues of BZDs in milk.  相似文献   

9.
In order to describe the lactation curves of milk yield (MY) and composition in buffaloes, seven non-linear mathematical equations (Wood, Dhanoa, Sikka, Nelder, Brody, Dijkstra and Rook) were used. Data were 116 117 test-day records for MY, fat (FP) and protein (PP) percentages of milk from the first three lactations of buffaloes which were collected from 893 herds in the period from 1992 to 2012 by the Animal Breeding Center of Iran. Each model was fitted to monthly production records of dairy buffaloes using the NLIN and MODEL procedures in SAS and the parameters were estimated. The models were tested for goodness of fit using adjusted coefficient of determination root means square error (RMSE), Durbin–Watson statistic and Akaike’s information criterion (AIC). The Dijkstra model provided the best fit of MY and PP of milk for the first three parities of buffaloes due to the lower values of RMSE and AIC than other models. For the first-parity buffaloes, Sikka and Brody models provided the best fit of FP, but for the second- and third-parity buffaloes, Sikka model and Brody equation provided the best fit of lactation curve for FP, respectively. The results of this study showed that the Wood and Dhanoa equations were able to estimate the time to the peak MY more accurately than the other equations. In addition, Nelder and Dijkstra equations were able to estimate the peak time at second and third parities more accurately than other equations, respectively. Brody function provided more accurate predictions of peak MY over the first three parities of buffaloes. There was generally a positive relationship between 305-day MY and persistency measures and also between peak yield and 305-day MY, calculated by different models, within each lactation in the current study. Overall, evaluation of the different equations used in the current study indicated the potential of the non-linear models for fitting monthly productive records of buffaloes.  相似文献   

10.
王茜茜  周敬宣  李湘梅  肖人彬 《生态学报》2011,31(20):6224-6230
为克服现有“两型社会”评价中存在的主观性强、不易处理高维数据等缺陷,提出了基于投影寻踪法的武汉市“两型社会”评价新方法。从资源、环境、经济、社会四个子系统出发,构建了武汉市"两型社会"评价指标体系;选取武汉市2000-2009年数据作为样本,将多维评价指标值投影为一维投影数据;引入加速遗传算法,优化投影指标函数寻求最佳投影方向;根据投影值大小对武汉市2000-2009年“两型社会”发展状况进行比较,利用最佳投影方向信息研究了各个指标对武汉市”两型社会“发展的影响程度。研究结果表明,2000-2009年,武汉市“两型社会”建设呈现出良好的发展态势,建成区绿化覆盖率、人均公共绿地面积、第三产业增加值占GDP比重、空气质量优良率、每千人口医院床位数、工业用水重复利用率、每万人在校大学生人数、单位GDP能耗、每万人拥有公共交通车辆等指标是武汉市“两型社会”建设的重要驱动因素。对此就武汉市建设“两型社会”提出了对策和建议。最后,指出投影寻踪模型为城市"两型社会"发展综合评价提供了一种值得探索和尝试的新方法。  相似文献   

11.
Recent reports on livestock environmental impact based on life cycle assessment (LCA) did not fully consider the case of the dairy goat. Assignment of an environmental impact (e.g. global warming potential) to a specific product needs to be related to the appropriate ‘unitary amount’ or functional unit (FU). For milk, the energy content may provide a common basis for a definition of the FU. To date, no ad hoc formulations for the FU of goat milk have been proposed. For these reasons, this study aimed to develop and test one or more predictive models (DPMs) for the gross energy (GE) content of goat milk, based on published compositional data, such as fat (F), protein, total solids (TS), solid non-fat matter (SNF), lactose (Lac) and ash. The DPMs were developed, selected and tested using a linear regression approach, as a meta-analysis (i.e. meta-regression) was not applicable. However, in the final stage, a control procedure for spurious findings was carried out using a Monte Carlo permutation test. Because several published predictive models (PPMs) for GE in cow milk and goat milk were found in the literature, they were tested on the same data set with which the DPMs were developed. The best-performing DPMs and PPMs were compared directly with a subset of the individual data retrieved from the literature. Overall, the paucity of direct measurements of the GE in goat milk was a limiting factor in collecting data from the literature; thus, only a small data set (n=26) was established, even though it was considered sufficiently representative of milks from different goat breeds. The three best PPMs based on F alone gave more biased estimates of the GE content of the goat milk than the three new DPMs based on F, F and SNF and F and TS, respectively. Accordingly, three different formulations of FU are proposed, depending on the availability of data including both F and TS (or F and SNF) or F alone. Even though several metrics can be used in defining the FU for milk to be used in LCAs of goat farming systems, the proposed FU formulations should be adopted in place of the similar energy-based ones developed for other dairy species.  相似文献   

12.
A chemiluminescent enzyme immunoassay (CLEIA) was compared to an ultraperformance liquid chromatography tandem mass spectroscopy (UPLC‐MS/MS) procedure for the analysis of zeranol and its metabolites in bovine tissue samples. Apparent recoveries from fortified samples by both methods were comparable at 0.5–4.0 µg/kg and a significant correlation was obtained. For CLEIA analysis, hapten mimicking the analyte was first synthesized and conjugated with the carrier protein bovine serum albumin as the immunogen to produce monoclonal antibody. The obtained antibody showed extensive cross‐reactivity toward zeranol metabolites (zearalanone). The limit of detection of CLEIA and UPLC‐MS/MS was 0.05 µg/kg and 0.5 µg/kg, respectively. Recoveries of both methods for fortified samples were higher than 75.0% with the coefficient of variation less than 15%. These results indicated that the combination of screening with CLEIA and confirmation with UPLC‐MS/MS for zeranol and its metabolites would be a reliable method for a large number of bovine samples. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

13.
张娜  姚凤梅  张佳华 《生态学杂志》2016,27(4):1152-1162
选择黑龙江省作为研究区域,根据主栽水稻生育期内所需积温选取3个代表性品种,重点分析增温和大气CO2肥效作用对不同熟性品种水稻产量的影响.采用2013年的逐日气象资料及开顶式气室(OTC)(3个CO2浓度:390、450和550 μmol·mol-1)试验资料对品种的遗传参数进行调试;然后采用经验证的CERES-Rice作物模型分别模拟了3个CO2浓度水平下,伴随温度升高1、2、3和4 ℃时早、中、晚熟品种水稻产量.结果表明: 随CO2浓度升高,不同品种水稻产量均上升;随温度升高,早熟品种产量持续下降,中、晚熟品种产量先上升再下降.若不考虑CO2肥效作用,除了中熟和晚熟品种在增温1 ℃时会有3.1%和0.27%的小幅增产外,其余均表现为减产,其中早熟品种减产幅度最大,增温4 ℃时减产高达57.7%,而中熟和晚熟品种减产10%左右.若考虑CO2肥效作用,450 μmol·mol-1 CO2浓度下,中熟和晚熟品种在增温2 ℃时仍增产0.75%和3.2%;550 μmol·mol-1 CO2浓度下,中熟品种在增温3 ℃时仍增产4.5%,晚熟品种在增温4 ℃时仍增产0.39%.而无论是否考虑CO2肥效作用,早熟品种在增温作用下均表现大幅度减产.与不考虑CO2肥效相比,大气CO2肥效作用有效提高了水稻产量,但CO2肥效对增产的贡献率在不同品种间差异不明显,且贡献率均小于10%.  相似文献   

14.
Abstract A standardised most-probable-number technique for estimating the number of myxomycete plasmodium-forming units (PFUs) in soils has been developed and tested experimentally. Application of the method to a local soil showed that the uppermost layers contained the most PFUs. Its application to 44 surface soils from various parts of the world detected myxomycetes in 36, of which 4 were desert soils. In general, highest numbers of PFUs (up to 9000·g−1 soil) were recorded in grassland and agricultural soils. The nature of the PFUs has not been definitely resolved but they are probably myxamoebae, myxoflagellates and microcysts.  相似文献   

15.
The Oriental fruit fly, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae) is a destructive fruit pest in a wide range of cultivated fruit crops and wild plants. This species is a potentially highly invasive fruit fly to Jeju area of Korea. This study was conducted to evaluate the effect of host plants distributed temporally on the population development of B. dorsalis. The temperature-dependent bionomic data for a synonymous group of B. dorsalis, including B. philippinensis, B. papayae, and B. invadens were collected from previous publications and combined to construct a population model of this pest and its thermal constant. We developed a stage-transition model of eggs, larvae and pupae, and an oviposition model for basic population modeling of the four common strains. We investigated the abundance of the host plants of B. dorsalis in a selected site in Jeju and parameterized them in terms of temporal availability to incorporate into the population model. The contribution of host plants for the population growth of B. dorsalis in the selected site was different according to the group of host plants. For example, B. dorsalis populations largely decreased by 93%, when host plants belong to Moraceae (mainly Ficus sp.) were removed in the simulation. Also, we found that the host plants of Prunus persica, Ficus carica, P. mume, Eriobotrya japonica in this order contributed greatly to population abundance of B. dorsalis in the selected area, which was important in terms of mid-season host plants connecting the early adult population of B. dorsalis to citrus plants in the late season. Finally, we discussed a seasonal management strategy against B. dorsalis while considering the availability of host plants and the biology of this fruit fly in an invaded area.  相似文献   

16.
doi: 10.1111/j.1741‐2358.2011.00465.x A cross‐sectional analysis of the prevalence of dental anxiety and its relation to the oral health‐related quality of life in patients with dental treatment needs at a university clinic in Switzerland Objectives: The aim of this observational, cross‐sectional study was to analyse the relationship between dental anxiety (DA) and health‐related quality of life aspects associated with oral conditions of a population with dental treatment needs in Switzerland. Methods: The measurements of DA were collected by means of two questionnaires, the Dental Anxiety Scale (DAS) and a Visual Analogue Scale (VAS). Oral health‐related quality of life (OHRQoL) was assessed with the Oral Health Impact Profile (OHIP). The sample included 223 patients enrolled at a university clinic which specialises in oral prosthetic rehabilitation and temporomandibular disorders. Of them, 78.9% were at or above the age of 50. Results: No gender or age dependencies were observed. A comparison of answers regarding OHRQoL and DA revealed a significant interdependence (p = 0.0118); highly anxious patients were 3.55 times more likely to suffer from poor quality of life compared with less anxious ones. Conclusion: This cross‐sectional study of mostly elderly patients seeking dental treatment in Switzerland found that increased DA was associated with an impaired OHRQoL. The average DA was slightly higher than the results of other industrialised countries and the average OHRQoL was reduced.  相似文献   

17.
Cation exchange chromatography combined with ligand (methotrexate) affinity chromatography on a column desorbed with a pH-gradient was used for separation and large scale purification of two folate binding proteins in human milk. One of the proteins, which had a molecular size of 27 kDa on gel filtration and eluted from the affinity column at pH 5-6 was a cleavage product of a 100 kDa protein eluted at pH 3-4 as evidenced by identical N-terminal amino acid sequences and a reduction in the molecular size of the latter protein to 27 kDa after cleavage of its hydrophobic glycosylphosphatidyl-inositol tail that inserts into Triton X-100 micelles. Chromatofocusing showed that both proteins possessed multiple isoelectric points within the pH range 7-9. The 100 kDa protein exhibited a high affinity to hydrophobic interaction chromatographic gels, whereas this was only the case with unliganded forms of the 27 kDa protein indicative of a decrease in the hydrophobicity of the protein after ligand binding.  相似文献   

18.
Linezolid is a new, promising antibacterial agent to treat severe infections. A rapid HPLC assay using UV detection for the determination in microdialysate and human plasma was developed. After sample preparation, using acetonitrile for plasma and water for microdialysate, 20 microl was injected and separated on a RP-18 column. Overall, the assay exhibited good precision and accuracy. The diffusion properties of linezolid investigated in in vitro microdialysis experiments revealed a mean relative recovery of 77.5% (CV: 5.4%; delivery and recovery experiments). Following characterization of linezolid in in vitro microdialysis, the setting is suitable for application in clinical studies.  相似文献   

19.
20.
The binding of thiamin diphosphate (ThDP) to yeast dimeric apotransketolase (apoTK) is accompanied by the appearance of a band in the absorption spectrum with maximum at 320 nm. The saturation function has been analyzed using a scheme that involves binding of ThDP to each subunit followed by the conformational transition of this subunit. It is assumed that the binding of ThDP to one subunit may affect the conformational transition of the other subunit. Rigorous mathematical expressions describing the dependence of the optical absorption on the total concentration of ThDP are first developed. Equilibrium constants and corresponding rate constants for the binding of ThDP to apoTK have been estimated. The negative cooperativity in the ThDP binding has been characterized by the function reflecting the dependence of the conformational change on the saturation of apoTK by ThDP.  相似文献   

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