共查询到19条相似文献，搜索用时 781 毫秒
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对牛奶中氯霉素残留的检测方法进行了研究,试验结果表明:①应用酶联免疫吸附法,牛奶中添加氯霉素标准品的浓度范围为0.45~4.05μg/L时,氯霉素的回收率为53%~115%;用高效液相色谱-串联质谱方法,牛奶中添加氯霉素标准品的浓度范围为0.05~0.20μ/L时,氯霉素的回收率为52%~118%,两种分析方法的技术指标均能达到检测要求。②在本实验中用酶联免疫吸附法对牛奶中的氯霉素残留量进行初筛(ELISA可有效避免假阴性,杜绝假阳性),进一步用高效液相色谱-串联质谱方法进行定量定性分析。两种方法准确可靠,可用于牛奶中氯霉素残留的检测。 相似文献
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氯霉素竞争ELISA检测方法的研究 总被引：2，自引：0，他引：2
用抗氯霉素的MAb 2G2建立了检测氯霉素的竞争ELISA,对主要影响因素进行了研究,其回归方程为y=0.3522x+0.5939,相关系数为RZ=0.9906,检测线性范围为0.098 ng/mL～25 ng/mL,半数抑制浓度(IC50)为1.848 ng/mL.检测限为0.135 ng/mL.与氯霉素琥珀酸钠交叉反应率为143%,与其它结构类似物和常见抗菌素的交叉反应率均小于0.01%.批内和批间变异系数分别为4.98%和9.42%,牛奶样的平均添加回收率为101.31%.所建立的检测氯霉素竞争ELISA法,符合检测氯霉素残留的要求,为氯霉素残留快速检测试剂盒的研制奠定了基础. 相似文献
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建立了适用于牛、羊奶样品中莫昔克丁残留的高效液相色谱荧光检测方法。以乙腈为提取液,C18固相萃取柱净化,并用N-甲基咪唑-乙腈(1+1,V/V)和三氟乙酸酐-乙腈(1+2,V/V)进行衍生化。乙腈+水(90+10,V/V)为流动相,荧光法定量。经测定,该方法对牛、羊奶中莫昔克丁的检测限为2 μg/kg,定量限为5 μg/kg。空白牛、羊奶中标准品莫昔克丁添加量分别为5、20、40和80 μg/kg时,牛奶中莫昔克丁平均回收率范围为75.5%～110%,其批内变异系数小于738%,批间变异系数小于7.87%;羊奶中莫昔克丁平均回收率范围为77.5%～95.6%,其批内变异系数小于5.06%,批间变异系数小于5.92%。该方法准确性强、灵敏度高,适用于牛、羊奶中莫昔克丁的快速检测。 相似文献
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本文建立了测定中药散剂中氯霉素含量的高效液相色谱分析方法。中药样品经乙酸乙酯-正己烷(1∶4)溶液提取,然后用稀盐酸溶液萃取,萃取液经SCX固相萃取小柱净化后测定。色谱柱:Kromasil-C18,150 mm×4.6 mm,5μm;流动相:甲醇+水(20∶80);流速:1.0 mL/min;进样体积:20μL;柱温:30℃;检测波长:278 nm。用高效液相色谱仪测定,外标法定量,氯霉素的检出限为0.2 mg/kg。在添加浓度5～20mg/kg范围内,氯霉素的添加回收率为80.6%～96.3%,批内RSD为1.91%～5.03%,批间RSD为2.03%～6.41%。氯霉素峰面积(y)与溶液浓度(x)在0.5～10μg/mL范围内呈良好的线性关系,线性回归系数大于0.999。 相似文献
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超高效液相色谱-串联质谱法检测动物源食品中氯霉素类药物及其代谢物残留 总被引：9，自引：4，他引：5
建立了动物源食品中氯霉素、甲砜霉素、氟苯尼考及氟苯尼考胺残留检测的超高效液相色谱-串联质谱(UPLC-MS/MS)分析方法.样品在碱性条件下用乙酸乙酯提取后,再用正己烷去除脂肪,浓缩后用BEH C18(50 mm×2.1 mm,1.7 μm)色谱柱分离,以乙腈和水为流动相进行梯度洗脱,流速为0.3 mL/min,多反应监测(MRM)模式检测.结果表明:四种药物在2～500 μg/L的系列浓度范围内均呈良好线性关系,相关系数r均大于0.990.样品中氯霉素的检测限为0.1 μg/kg,定量限为0.2 μg/kg;甲砜霉素、氟苯尼考和氟苯尼考胺的检测限为0.5 μg/kg,定量限为1 μg/kg.本方法氯霉素在0.2～1 μg/kg的添加浓度范围内,甲砜霉素、氟苯尼考及氟苯尼考胺在1～50 μg/kg的添加浓度范围内平均回收率均为70%～120%,相对标准偏差(RSD)均小于20%.该方法具有简便快捷、灵敏度高、定性准确等特点. 相似文献
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酶联免疫法测定牛奶中氯霉素应注意的事项 总被引：2，自引：0，他引：2
古丽沙依拉·斯坦别克 《新疆畜牧业》2013,(8):46-48
本文用酶联免疫法对牛奶中氯霉素的残留进行检测分析,对使用氯霉素试剂盒和利用酶联免疫吸附试验方法测定牛奶中氯霉素含量时应注意的事项,分别从牛奶的储存和取样、试剂盒的选择、保存以及检测时的操作步骤等几个方面进行讨论,并且对在检测过程中遇到的具体问题在文章中进行讨论。 相似文献
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The objective of the present paper was to obtain haematological and biochemical parameters of calves during their milk feeding. Another goal was to compare a current feed ration containing the commercial feed mixture Biosan with two alternative rations comprising skimmed milk and fat supplement. The effect of milk drink acidification and the effect of the physical form of fat added to skimmed milk were investigated. the calves were divided into six groups, by 6 to 8 calves each (P1-Biosan, PP1-acid variant, P2-skimmed milk+fat concentrate powder KMKS, PP2-acid variant, P3-skimmed milk+fat paste, PP3-acid variant). The highest average daily liveweight gains were recorded in calves fed on unacidified skimmed milk with fat paste supplement (1.074 kg)-Tab. I. The highest average daily liveweight gains were observed in calves fed on fat paste enriched milk drink (P3) while the calves administered milk with fat concentrate powder (P2) had only slightly higher average daily weight gains than the calves on Biosan diet (group P1). The growth of daily weight gains as a result of diets containing acidified milk (PP1 and PP2) is also a positive finding; this growth is even statistically significant in the former case (P < 0.05). The calves showed hypohaemoglobinaemia from the beginning of the experiment (51.3-69.0 g/l) and the low haematocrit value (0.29-0.43 l/l), Tab. II, while the plasma iron level was paradoxically high (Tab. V).(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
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建立超高效液相色谱-串联质谱法同时测定牛乳中21 种β-兴奋剂残留量。样品经酶解、固相萃取柱净化，采用Acquity UPLC BEH C18色谱柱（50 mm×2.1 mm，1.7 μm）分离，以0.1%甲酸-10%甲醇水溶液为流动相梯度洗脱，在电喷雾离子源正离子模式下，采用多反应监测模式，对21 种β-兴奋剂进行定性和定量分析。结果表明：该方法的定量限为0.05 μg/kg，在0.05、0.10、0.50 μg/kg 3 个不同添加水平下，平均回收率为61.0%～124.3%，相对标准偏差为2.39%～10.66%；该方法稳定、准确、灵敏度高，可用于牛乳中21 种β-兴奋剂残留量检测。 相似文献
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M C Antognoli M D Salman J Triantis J Hernández T Keefe 《Journal of veterinary diagnostic investigation》2001,13(2):111-116
The objective of this study was to evaluate the use of a one-tube nested polymerase chain reaction (OTN PCR) with 5 concentration and lytic treatments for the detection of Mycobacterium bovis in experimentally inoculated milk samples (spiked samples). OTN PCR and the following treatments were tested in inoculated samples: 1) centrifugation; 2) C18-carboxypropylbetaine + capture resin 1 + Proteinase K (CB18-CH-PK); 3) centrifugation + capture resin 1 + Proteinase K; 4) centrifugation + capture resin 2 + Proteinase K; and 5) centrifugation + immunomagnetic separation (IMS). The OTN PCR and the 5 treatments were evaluated in 2 different sets of spiked milk samples. One set consisted of 10-fold serial dilutions of a phenol-killed M. bovis in milk to final concentrations ranging from 5 to 50,000 cells/ml of milk. The other set of samples consisted of 2.5 serial dilutions of milk spiked with M. bovis to final concentrations ranging from 20.5 to 5,000 cells/ml of milk. Each treatment was repeated 5 times at each cell concentration. CB18-CH-PK and IMS were significantly more sensitive than other treatments. The lowest detection limit for these techniques was 20-50 cells/ ml of spiked milk. The specificity of OTN PCR in this study was high as demonstrated by the lack of DNA amplification products when M. bovis cells were not present in the samples. [The OTN PCR used in conjunction with CB18-CH-PK or IMS could be effectively used as a diagnostic and/or screening test for the detection of M. bovis in milk from herds with bovine tuberculosis.] 相似文献
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小尾寒羊泌乳期母羊能量需要量及代谢规律研究 总被引：4，自引：0，他引：4
选择有代表性的小尾寒羊泌乳母羊6只，分成哺育单羔和双羔两组，每组3只，分泌乳前期（1～30天），泌乳中期（31～60天）和泌乳后期（61～90天）3个阶段进行饲养试验、消化代谢试验、呼吸测热试验及屠宰试验等研究。两组试羊均按NRC（1978）推荐的绵羊泌乳期哺育双羔母羊能量需要量供给代谢能和其它养分。结果表明，在本研究条件下，小尾寒羊泌乳母羊（包括哺育单、双羔者）在整个泌乳期内的平均日干物质（DM）、有机物质（OM）、代谢能（ME）和泌乳量分别为1689g，1571g，19．893MJ和653g。DM、OM和总能（GE）表观消化率分别为70.71％，72．58％和70．34％，代谢率（MEI／DEI）为84．89％。甲烷能占GEI的9．18％。每日畜体产热量（HP）为625．5KJ／kgW0.75。研究还表明：小尾寒羊泌乳母羊的每日维持代谢能和净能需要量分别为582．6和460KJ／kgW0.75，每户1kg原乳需要10802KJ的代谢能。维持效率为0．790泌乳效率为0．479，HI占GEI的18．10％。分析结果证明，试羊的泌乳量、采食量、畜体产热量和能量转化效率在单、双羔之间均无显著差异（P＞0．05）。小尾寒羊泌乳母羊的代谢能总需要量（MER）可用下式估计：羊羔：MER＝576．9W0.75＋10810M；双羔：MER＝588．2W0.75＋10794M；平均：MER＝582．6W0.75＋1 相似文献
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建立发酵乳及果酱中苯甲酸、山梨酸、糖精钠和安赛蜜的反相高效液相色谱分析方法。用水做提取剂,在C18反相色谱柱上进行分离,采用乙酸铵缓冲溶液（20 mmoL/L,pH 4.6）-甲醇为流动相进行等度洗脱,用于苯甲酸和山梨酸测定时流动相A、B的体积比为85∶15,糖精钠和安赛蜜测定时为95∶5,采用紫外检测器在254 nm波长处检测,外标法定量。结果表明：发酵乳样品中苯甲酸、山梨酸、糖精钠和安赛蜜的添加量为1～20 mg/kg时,加标回收率为92.0%～102.4%;果酱样品中苯甲酸、山梨酸、糖精钠和安赛蜜的 相似文献
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OBJECTIVE: To determine the correlations between three bacterial dermatoses in cattle, milk production and bulk-milk somatic cell count (BMSCC). DESIGN: Field observations in three dairy cattle herds. METHODS: Milk production, BMSCC, fertility and all herd diseases were recorded by computerised dairy management systems. Each herd was visited twice weekly and the clinical signs, course of diseases and morbidity and culling rates were noted. Bulk-tank milk was sampled twice monthly and analysed for somatic cell count. Bacteriological and histological examinations were carried out from samples collected from affected animals in the respective herds. RESULTS: The acute exudative form of dermatophilosis was diagnosed only in first-calving cows. The morbidity rate was 53% and the culling rate was 16% of the affected animals. The BMSCC increased by a factor of 2.4 times, and there was an average loss of milk production of 30%/cow/day in affected animals. Ulcerative lymphangitis was diagnosed in first-calving cows (22%) and older cows (15%). The culling rate was 28%. The BMSCC increased by a factor of 17.3 times, and the average loss of milk production was 5.5%/affected animal/day. Papillomatous digital dermatitis (PDD) was diagnosed in first-calving cows (25%) and in older cows (18%). The culling rate was 8%. The BMSCC increased by a factor of two times, and the average loss of milk production was 1.7%/affected animal/day. CONCLUSIONS: The correlations between three skin diseases (ulcerative lymphangitis, dermatophilosis, papillomatous digital dermatitis), milk production and BMSCC have been found to be unfavourable. 相似文献
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Crossbreeding effects for litter and lactation traits in a Saudi project to develop new lines of rabbits suitable for hot climates 总被引：1，自引：1，他引：0
A.M. Al-Saef M.H. Khalil A.H. Al-Homidan S.N. Al-Dobaib K.A. Al-Sobayil M.L. García M. Baselga 《Livestock Science》2008,118(3):238-246
A five-years crossing scheme involving the Spanish V line (V) and Saudi Gabali (S) rabbits was practiced to produce 14 genetic groups: V, S, 1/2V1/2S, 1/2S1/2V, 3/4V1/4S, 3/4S1/4V, (1/2V1/2S)2, (1/2S1/2V)2, (3/4V1/4S)2, (3/4S1/4V)2, ((3/4V1/4S)2)2, ((3/4S1/4V)2)2, Saudi 2 (a new synthetic line) and Saudi 3 (another new synthetic line). A total of 3496 litters from 1022 dams were used to evaluate litter size at birth (LSB) and weaning (LSW), litter weight at birth (LWB), litter weight at 21 d (LW21) and litter weight at weaning (LWW), pre-weaning litter mortality (PLM), milk yield at lactation intervals of 0–7 d (MY07), 0–21 d (MY021), 0–28 d (TMY) and milk conversion ratio as g of litter gain per g of milk suckled during 21 d of lactation (MCR021). A generalized least squares procedure was used to estimate additive and heterotic effects (direct, maternal, and grand-maternal).The comparison among V, S, Saudi 2 and Saudi 3 showed a complementarity between V and S. Line V was superior for LSB, LSW, LWB, PLM, MY07, MY021 and TMY, while line S was superior for the other traits (LW21, LWW and MCR021). Saudi 2 and Saudi 3 had the means equal to or higher than the founder lines (V or S) for all traits. Saudi 2 showed better values in litter size and pre-weaning litter mortality compared to Saudi 3 with no significant differences for the other traits. Concerning crossbreeding parameters, direct additive effects were significant for all traits, ranging between 12.3% and 31.8% relative to the average of the means of V and S. All estimates for direct heterosis except LWB and MCR021 were significant and ranged from 5.3% to 27.5%. No estimates for maternal additive effects and grand-maternal additive and heterotic effects were significant. Only estimates for maternal heterotic effects of LSB and LSW were significant (8.6% and 10.6%, respectively). 相似文献
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Tran H Moreno R Hinkle EE Bundy JW Walter J Burkey TE Miller PS 《Journal of animal science》2012,90(9):3049-3059
An experiment was conducted to evaluate the effects of dietary lactose alone or in combination with a yeast-dried milk product (50% dried near-dated milk and 50% dried yeast) on growth performance, fecal microbiota, and immune status in nursery pigs (Sus scrofa). A total of 108 pigs (age, 20 ± 1 d; initial BW, 6.07 ± 0.03 kg) were randomly allotted to 18 pens (6 pigs/pen; 6 pens/treatment). Dietary treatments were: 1) control, 2) control + lactose, and 3) control + lactose + 5% yeast-dried milk. Except for the control diet, diets in Phase 1 (wk 1 and 2), 2 (wk 3 and 4), and 3 (wk 5) contained 20, 15, and 5% total lactose, respectively. Blood samples were collected from all pigs at d 0, 14, 28, and 35 to determine circulating IgG, IgA, and tumor necrosis factor (TNF)-α concentrations. At d 0, 7, and 14, fecal samples were collected (n = 18; 6 pigs/treatment) to evaluate fecal microbiota using PCR-denaturing gradient gel electrophoresis. Compared with pigs fed the control diet, pigs fed lactose and lactose with yeast-dried milk had greater (P < 0.05) ADG and tended (P = 0.07) to have greater BW and ADFI during Phase 1. There were no differences for BW, ADG, or ADFI during Phase 2, 3, or the overall experimental period. A main effect of treatment was observed for circulating IgA where control pigs had greater (P < 0.01) IgA compared with pigs fed lactose with or without yeast-dried milk; however, no effects of treatment were observed (P > 0.10) for circulating IgG or TNF-α. No differences (P > 0.10) in microbial diversity indices were observed on d 7 or 14 among treatments. However, a shift in microbial composition was observed on d 7, with lactose-fed pigs having greater (P < 0.05) putative L. johnsonii staining intensity compared with control pigs and pigs fed lactose plus yeast-dried milk. On d 14, L. delbrueckii was eliminated (P < 0.04) by feeding lactose with or without yeast-dried milk. This research indicates that growth performance, immune status, and fecal microbiota are affected by dietary inclusion of lactose alone, or in combination with yeast-dried milk. 相似文献
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Recent publications indicate genetic variation in milk production traits on proximal BTA14, which cannot be explained solely with genetic variation in the DGAT1 gene. To elucidate these QTL effects, animals from a German Holstein granddaughter design (18 families, 1,291 sons) were genotyped for CYP11B1 (V30A) and DGAT1 (K232A) polymorphisms. Frequencies of alleles of maternal descent were estimated for CYP11B1(V) (0.776) and DGAT1(K) (0.549). Allele substitution effects (alpha/2) were first calculated for both alleles in separate models and then in a joint model. From the joint analysis, CYP11B1(V) effects on fat content (+0.04%) and protein content (+0.01%) were positive. Effects on milk yield (-82 kg), fat yield (-0.5 kg), and protein yield (-1.9 kg) were negative. Compared with the individual analysis, DGAT1(K) effects on fat content (+0.28%), protein content (+0.06%), and milk yield (-258 kg) were reduced; fat yield (+10.8 kg) was enhanced; and protein yield (-3.8 kg) was reduced. In the joint analysis, allele substitution effects of CYP11B1(V) and DGAT1(K) together explained more of the variation in milk production traits than DGAT1(K) alone. Further significant effects were found for CYP11B1(V) and DGAT1(K) among 6 reproduction traits and 14 conformational traits. These observations indicate a possible negative influence of DGAT1(K) on maternal nonreturn rate, and thus, on length of productive life. 相似文献