柱后衍生阳离子交换色谱法测定动物源性饲料原料及饲料中的生物胺

试验采用柱后衍生阳离子交换色谱技术建立同时测定动物源性饲料原料及饲料中组胺、腐胺、尸胺、亚精胺、精胺和酪胺的分析方法.样品以2％磺基水杨酸溶液提取,4％磺基水杨酸溶液和二氯甲烷净化提取样液,采用氨基酸分析仪用阳离子交换色谱柱(LCA K17)、以柠檬酸K液为流动相分离6种生物胺,茚三酮溶液衍生后,可见光检测器于570 ...     

牛肝中苯并咪唑类药物残留的高效液相色谱检测方法

建立了牛肝组织中苯并咪唑类药物(阿苯哒唑,噻苯哒唑和奥芬哒唑)多残留检测的高效液相色谱法.用乙酸乙酯提取牛肝组织样品中的药物,提取液浓缩后加入酸性乙醇和正己烷分配脱脂,过C18固相萃取柱净化.以甲醇-磷酸二氢铵缓冲液为流动相,反相高效液相色谱紫外检测法检测.方法的平均回收率为78.8%,平均变异系数为2.18%.3种药物的检测限为8 μg/kg,定量限为25 μg/kg.     

液相色谱-串联质谱法测定牛肉中加替沙星残留量的研究

建立牛肉中加替沙星残留量检测的液相色谱-串联质谱(liquid chromatography-tandem mass spectrometry, LC-MS/MS)方法。牛肉样品经80%(V/V)乙腈溶液提取, Prime HLB固相萃取柱净化。采用0.1%甲酸(V/V)-甲醇溶液(A)和0.1%甲酸(V/V)-水溶液(B)进行梯度洗脱, 电喷雾离子源正离子扫描模式(ESI+),多反应监测(MRM),内标法定量。结果表明,加替沙星进样浓度在1～50 ng/mL范围内与峰面积呈良好的线性关系(r₂^＝0.999);方法检出限和定量限分别为1.0和2.0 μg/kg;在2.0、4.0、20 μg/kg 3个添加水平上,回收率在64.2%～113.4%之间,相对标准偏差为5.0%～9.7%(n=6)。本方法快速、准确、灵敏,适用于牛肉中加替沙星残留量检测。     

高效液相色谱法检测饲料中咪达唑仑的含量

文中建立了高效液相色谱法测定饲料中咪达唑仑(midazolam)含量的方法。样品由乙腈提取,垂直振荡离心后使用固相萃取C18柱进行净化,色谱柱为Agilent Eclipse XDB-C18(4.6 mm×250 mm,5μm),流动相为甲醇-水梯度,检测波长254 nm。实验结果:咪达唑仑最低定量限为1 mg/kg;猪配合饲料回收率为70%～100%,猪预混合饲料回收率为60%～100%,猪浓缩饲料回收率为65%～100%;相对标准偏差均小于10%。结果提示,用高效液相色谱法测定饲料中咪达唑仑的含量,方便、简单、有效性高。     

Detection of anticoagulant rodenticides (4-hydroxycoumarins) by thin-layer chromatography and reversed-phase high-performance liquid chromatography with fluorescence detection

The detection of 4-hydroxycoumarin rodenticides in poisoned domestic animals requires a highly sensitive method as tissue and serum levels of anticoagulants may be very low owing to rapid elimination, metabolism or post-mortem degradation. Thin-layer chromatography (TLC) and reversed-phase high-performance liquid chromatography (RP-HPLC) with fluorescence detection were used to identify the anticoagulants in spiked tissues and in suspicious samples. The analysis of ten suspicious samples highlighted the limitations of both methods. Only the three samples of baits were found positive by TLC whereas one of the five anticoagulants was detected in eight samples by RP-HPLC with fluorescence detection. Therefore, RP-HPLC with fluorescence detection proved to be the more sensitive method for detecting low levels of 4-hydroxycoumarins in blood serum, liver and ingesta, whereas TLC is usually sufficient for analysing baits.Abbreviations RP-HPLC reversed-phase high-performance liquid chromatography - TLC thin-layer chromatography     

薄层色谱法检测环丙氨嗪中5种有关物质

研究了5种环丙氨嗪有关物质和环丙氨嗪在有关物质检查薄层色谱中的响应相关性.结果表明,可以用自身对照替代对照品对照的方法对有关物质进行检测.     

鸡组织中尼卡巴嗪残留HPLC检测方法的研究

建立了尼卡巴嗪标识残留物在鸡组织中残留的HPLC检测方法.样品用乙腈提取,正己烷脱脂,C18固相小柱净化.以乙腈:水(52: 48)为流动相,紫外检测器在波长340 nm处检测.在该检测条件下,尼卡巴嗪标示残留物DNC的检测限为31.25μg/kg,定量限为100μg/kg.DNC工作液在31.25～8 000 μg/kg范围内药物浓度与峰面积呈良好的线性关系(r=0.999 9).尼卡巴嗪在鸡肌肉、肝脏和肾脏中添加浓度分别为0.1、0.2和0.4 μg/g时,样品回收率在80.06%～89.87%之间.批内变异系数小于7.09%,批间变异系数小于6.34%.     

肉牛养殖中饮水管理注意事项

随着肉牛养殖业的不断发展,养殖户越来越注重精粗饲料的高效利用以及饲养管理水平的提升,往往容易忽视养殖过程中最基础同时也是非常重要的环节——饮水管理。适宜的饮水条件不仅可以降低肉牛疾病的发生,还可提高饲料消化率及生产性能,从而提高经济效益。     

鸡肝组织中拉沙洛西钠残留的高效液相色谱检测方法

建立了鸡肝组织中拉沙洛西钠残留的高效液相色谱检测方法.甲醇提取鸡肝组织样品中残留的拉沙洛西钠,硅胶柱净化,以磷酸盐缓冲液-乙腈-甲醇作为流动相,反相高效液相色谱-荧光检测法检测.方法平均回收率为82.1%,平均变异系数为7.75%,方法的检测限为0.02 mg/kg.     

肉牛舍走向对夏季舍内环境的影响

为了研究肉牛舍走向对舍内环境指标的影响,试验选取2种不同走向的牛舍,测定夏季舍内温度、相对湿度、风速以及二氧化碳、氨气浓度。结果表明:东西走向牛舍内的风速显著高于南北走向牛舍(P<0.05),有效温度及有害气体浓度极显著低于南北走向牛舍(P<0.01),2种牛舍内温度和相对湿度无显著差异(P>0.05)。     

康乐县肉牛产地检疫存在的问题及应对措施

随着康乐县肉牛产业的发展壮大,动物疾病防控工作显得尤为重要,如何搞好肉牛出栏产地检疫,保证上市交易肉牛健康,是摆在我们面前的首要问题,但由于我县肉牛养殖场、散养户多,宣传不到位,养殖者意识不强,交易市场开办方主体责任不明等原因导致肉牛产地检疫工作严重滞后。     

Prevalence of Neospora antibodies in beef cattle in New Zealand

dAim:To estimate the prevalence of Neospora infection in a sample of New Zealand beef cattle.

dMethods: The prevalence of Neospora caninum infection in New Zealand beef cattle was estimated by collecting blood at slaughter from 499 beef cattle from 40 different farms at 2 slaughter plants in the North Island and 1 in the lower South Island. Sera were tested using an ELISA against Neospora tachyzoite antigen.

dResults: The prevalence of seropositive cattle was 2.5% (n=120), 3.6% (n=166) and 2.3% (n=213) at the plants surveyed, the overall prevalence being 2.8%. The serologically positive cattle came from 9 farms, 3 of which had more than 1 positive animal. The highest prevalence recorded amongst animals from 1 farm was 4/13 (31%), in a group of young steers.

dConclusion: Neosporosis appears to be present at a lower level in the New Zealand beef cattle population than in the New Zealand dairy cattle population. Nevertheless, from the high seroprevalence evident amongst young cattle on 1 farm, we suggest that Neospora may be a cause of infertility in beef cattle in this country.     

Change of clopyralid concentration in recycled beef cattle compost

Composting of beef cattle manure using sawdust or recycled compost as a bulking agent was investigated for the management of clopyralid risk, such as changes in the clopyralid concentration and the mechanism of clopyralid accumulation caused by recycled compost. These raw materials were composted with laboratory equipment, which was controlled at 60℃ after the temperature peak by autothermal composting. Clopyralid concentration did not changed during composting in the thermophilic phase; on the contrary, it increased because clopyralid accumulated in compost when recycled compost was used repeatedly as a bulking agent. The clopyralid accumulation ratio (ratio of clopyralid concentration to that in the first compost) could be explained by a model using a recurrence formula, and a correlation existed between the calculated (model) accumulation ratios and measured accumulation ratios (R² = 0.78). Using this model, the excessive accumulation of clopyralid could be controlled when using recycled compost as a bulking agent with lower moisture content or when part of the recycled compost was replaced by another bulking agent, even if recycled compost had high moisture content. In future work, the model and its considerations should be verified in a field test.     

Myelodysplasia as a cause of hindlimb ataxia in two beef calves

Myelodysplasia is a general term referring to abnormal development of the spinal cord. Unless associated with vertebral malformations, it can be difficult to distinguish clinically from other causes of spinal cord disease. These case reports describe the clinical and pathological findings in two calves with a distinctive non-progressive pelvic limb ataxia. The syndrome was observed in two calves on a large, extensively managed beef cattle property near Richmond, north Queensland. Both calves had similar clinical signs, including hindlimb ataxia with swaying of the pelvis and a well-coordinated bilateral hopping-like action. The differential diagnoses are discussed. A focal or diffuse myelodysplasia should be suspected in calves that have exhibited a non-progressive hindlimb ataxia from birth.     

中草药添加剂对河西牛肉挥发性化合物的影响

为了研究中草药添加剂对牛肉挥发性化合物的影响,试验选取成年河西肉牛,饲养过程分为中草药组和对照组,屠宰后运用气相色谱-质谱联用技术(GC-MS)进行牛肉挥发性化合物含量的测定。结果表明,中草药组和对照组牛肉挥发性物质在种类和含量上都有差异,对照组烃类、酮类、芳香族化合物、含硫类含量均高于中草药组,而中草药组醛类物质的含量比对照组高30.11%,同时认为中草药的添加与α-蒎烯、β-丁香烯、柠檬烯等特征挥发性化合物的产生有关。说明中草药添加剂能够增加牛肉中醛类、醇类以及杂环类化合物的含量,并能产生一些中草药添加剂所特有的挥发性化合物。     

The effects of using lactic acid bacteria inoculants in maize silage on the formation of biogenic amines.

Silages from five ripened varieties of silage maize with dry matter contents ranging between 275 and 410 g/kg were prepared in five laboratory experiments. Whole-plant maize was fermented at 22 degrees C and silages were then stored at the same temperature for 4 months. Spontaneously fermented silages were prepared as control variants and compared with silages inoculated with commercial strains of Lactobacillus plantarum, Lactobzcillus buchneri and a mixed preparation Microsil containing L. plantarum, Lactobacillus casei, Enterococcus faecium and Pediococcus pentosaceus. The starter cultures were applied at doses 5 x 10(5) and 5 x 10(6) CFU/g of chopped maize. Seven biogenic amines and polyamines were extracted from silages with perchloric acid and determined as N-benzamides by micellar electrokinetic capillary chromatography. Common chemical criteria of silage quality were also determined. All three inoculants, mainly at the higher dose, decreased significantly contents of tyramine, putrescine and cadaverine, three undesirable amines occurring at the highest levels. L. plantarum was the most effective. Contents of histamine and tryptamine were low in all experimental silages. Also relatively low were levels of polyamines spermidine and mainly of spermine.     

Effects of an environmental enrichment using a drum can on behavioral, physiological and productive characteristics in fattening beef cattle

To evaluate the effects of environmental enrichment on behavioral, physiological and productive characteristics, 71 Japanese Black × Holstein steers (8 months of age; 299.5 ± 22.6 kg) were allocated to three pens in two repetitive experiments. Pen C (n = 11 and 12) consisted of a feeding alley for grain feed, a trough for dry hay, a water bowl and a resting space as a control pen. Pen D (n = 12 and 12) included a drum can (58 cm diameter × 90 cm height) containing hay. Pen GD (n = 12 and 12) included a drum can that was placed around artificial plastic turf (30 × 120 cm) for grooming. The drum cans were removed after 5 months of installation. Behavioral observations were made for 2 h at 10 min intervals after feeding on three successive days each month for 10 months. Agonistic interactions were also continuously observed for 1 h after feeding to assess the dominance order (DO). Sampling blood and measuring bodyweight were performed bimonthly. The steers used the drum can frequently for 3 months after installation (1st, 2nd, 3rd months vs 4 months, all P < 0.05). The frequency of total eating of grain feed and hay was higher in pen D and pen GD than in pen C (both P < 0.01), while it was lowest in pen GD after removal of the drum can (P < 0.05). Grooming at the drum can was observed more frequently in pen GD than in pen D (P < 0.05). After they finished eating the grain feed, they ate hay at the drum can that contained additional hay rather than at the trough for hay (P < 0.01). Plasma dopamine concentrations were higher in pen D than in pen C (P < 0.05), and serum triglyceride concentrations were higher in pen C than in pen GD (P < 0.05) during the installation of the drum can. After removal of the drum can, serum total cholesterol concentrations became higher in pen D and GD than in pen C (both P < 0.05). Average daily gain correlated positively with the frequency of eating hay at the drum can in pen D (r_s = 0.52, P < 0.01). In pen GD, the frequency of using the drum can correlated negatively with DO (r_s = ?0.59, P < 0.01). Carcass belly fat was thicker in pens D and GD than in pen C (both P < 0.01). In pen GD, the frequency of eating hay (r_s = 0.79, P < 0.01) and grooming at the drum can (r_s = 0.63, P < 0.05) correlated positively with the marbling score. Although social factor affected the steers using the drum can, installing it in the early fattening stage encouraged the steers to eat and groom there and resulted in better carcass characteristics through the prolonged physiological positive effects.     

张掖肉牛世代选育繁殖性能研究

【目的】研究张掖近20年来选育的肉牛新品种各世代公、母牛繁殖性能,为种群扩繁和高效推广利用提供科学依据。【方法】利用张掖肉牛新品种选育技术资料,对4个世代的选育张掖肉牛配种、产犊记录进行分类汇总、统计分析,数据用Excel 2010进行初步整理。【结果】张掖肉牛母牛初配年龄为 15～18月龄, 初配体重为380～420公斤, 产犊月龄为 21～24月龄。横交选育的不同世代母牛表现出较好的繁殖性能, 平均犊牛成活率 97.9 %, 繁殖成活率 81.74 %。     

动物双歧杆菌A6体内外安全性评价

本研究对动物双歧杆菌A6进行了体外及体内的安全性评价,为菌株应用提供基础保障。通过体外试验评价了A6的抗生素敏感性和生物胺的生成;通过体内试验评价了A6的经口毒性及移位风险。试验结果表明,A6不存在菌株特有的抗生素敏感性,排除了抗生素耐性横向转移的风险;在脱羧酶培养基中培养,未发现该菌株产生生物胺;灌胃试验发现,将该菌株分别以2×10^8cfu/mL、2×10^9cfu/mL、2×10^10cfu/mL低中高三种剂量灌胃小鼠,每只小鼠每天灌胃0.2mL,连灌28d,结果小鼠无不良反应,在其血液、肾脏、肝脏未发现该菌株的移位现象。在对动物双歧杆菌A6安全性评价中,未发现菌株的不安全因素。