同位素稀释―高效液相色谱―线性离子阱质谱法测定总膳食乳类样品中8种三嗪类农药

本试验旨在建立用同位素稀释―高效液相色谱―串联线性离子阱质谱法(HPLC-LIT-MS)同时测定总膳食乳类样品中8种三嗪类农药的检测方法。在中国144个采样点采集总膳食乳类样品,在待测样品中加入氘代同位素内标,用乙腈经超声提取,凝胶渗透色谱(GPC)净化。以乙腈和含10mmol/L甲酸铵和0.1%甲酸的水溶液为流动相,目标化合物经CAPCELL PAK CR 1∶20色谱柱分离,采用电喷雾电离,选择反应监测(SRM)正离子模式监测二级子离子。以一一对应的氘代同位素为内标物,内标法定量,计算样品中三嗪类农药的含量。总膳食乳类样品中8种三嗪类农药的平均添加回收率为83.9%~103.3%;相对标准偏差为2.5%~9.1%;检出限(LODs)为0.003~0.300μg/kg。结果表明,该方法精密度和准确度均满足总膳食乳类样品中8种三嗪类农药的膳食暴露评估要求。     

高效液相色谱-质谱联用法同时测定鸡肉中2种金刚烷胺类药物和12种喹诺酮类药物残留

为建立一种同时测定鸡肉组织中2种金刚烷胺类药物和12种喹诺酮类药物残留的高效液相色谱-质谱联用法,试验将鸡肉组织经1％乙酸的乙腈提取,乙腈饱和的正己烷脱脂,以0.1％甲酸水和甲醇为流动相进行梯度洗脱;样品质谱采用电喷雾电离,正离子扫描,多反应监测模式检测,同位素内标法定量.结果 显示:14种药物在1～100 ng/mL...     

固相萃取-高效液相色谱-串联质谱法同时测定鸭蛋中4种硝基咪唑类药物残留

为建立并优化一种同位素-高效液相色谱-串联质谱法同时测定鸭蛋中4种硝基咪唑类药物（甲硝唑、地美硝唑、羟基甲硝唑、羟基地美硝唑）残留的检测方法,将样品经柠檬酸缓冲液和乙腈提取,超声波助提,平行蒸发仪减压浓缩后,用混合强阳离子固相萃取柱（MCX）净化。以Kinetex F5五氟苯基色谱柱分离,0.1%甲酸水和甲醇溶液为流动相进行梯度洗脱,在电喷雾离子源（ESI）正离子模式下,采用多反应监测模式（MRM）进行检测,以同位素内标法定量分析。结果显示:4种硝基咪唑类药物在0.5～200.0μg/L范围内线性关系良好,相关系数均大于0.997,加标回收率为90%-110%,相对标准偏差（RSDs）为4.76%～7.17%。结果表明,该方法回收率高、准确性好,可完全满足对4种硝基咪唑类药物残留检测的定性、定量需求,为食品中污染物监测提供了有效的技术支撑。     

高效液相色谱-串联质谱法同时测定水产品中残留的12种喹诺酮和磺胺类药物

建立水产品中有12种喹诺酮类（QNs）和磺胺类（SAs）药物残留量同时测定的高效液相色谱-串联质谱方法。以氘代试剂做内标,选择乙腈提取,用正己烷脱脂,旋转蒸发浓缩,采用LC—MS／MS选择反应监测（SRM）正离子模式测定进行定性、定量分析。结果表明,12种喹诺酮类（QNs）和磺胺类（SAs）药物的检出限（LOD）为1．0μg／kg,定量限（LOQ）为2．0μg／kg,检测结果的相对标准偏差为3．5％～14．6％（n=6）,加标回收率达到69．5％～121．9％。该方法具有比较高的重现性和选择性,在水产品中喹诺酮类和磺胺类药物的残留测定中具有很好的应用前景。     

禽蛋中甲硝唑残留的固相萃取-高效液相色谱-串联质谱检测方法建立

为建立优化固相萃取-高效液相色谱-串联质谱法测定禽蛋中甲硝唑残留的方法,以甲硝唑-D4为内标,将禽蛋样品（鸡蛋、鸭蛋、鹅蛋、鹌鹑蛋）用10 mL乙酸乙酯-甲醇（体积比19:1）进行提取离心,将上清液氮吹后用4 mL乙腈-水（体积比4:1）复溶,用PRiME HLB固相萃取柱净化;以Kinetex F5五氟苯基色谱柱分离,0.1%甲酸水和0.1%甲酸乙腈为流动相进行梯度洗脱,在电喷雾离子源（ESI）正离子模式下,采用多反应监测模式（MRM）进行检测,以内标法进行定量分析。结果显示：甲硝唑标准溶液在0.1~50.0 μg/L范围内呈现良好的线性关系,相关系数（R2）为0.999 81;甲硝唑在禽蛋中的检出限（LOD）和定量限（LOQ）分别为0.15 μg/kg和0.50 μg/kg,回收率为93.70%~106.83%,相对标准偏差（RSD）为1.66%~3.80%。结果表明,本研究建立的方法前处理过程简单,易于操作,结果准确,适合大批量不同种类禽蛋样品的检测,能够满足禽蛋中甲硝唑残留风险监测的需求。     

固相萃取/UPLC-MS/MS法检测饲料中18种喹诺酮类药物的研究

为了建立超高效液相色谱-串联质谱法测定饲料中18种喹诺酮类药物的分析方法,以0.1%乙酸乙腈提取饲料样品中的待测物,HLB柱净化,超高效液相色谱-串联质谱法测定,氘代同位素内标法定量。18种喹诺酮类药物在线性范围为0~1.0 mg/L,线性关系良好,相关系数分别在0.9989~0.9999之间,方法的检测限为0.005~0.2 mg/kg。在不同饲料中添加浓度范围为0.1~5.0 mg/kg,平均回收率为43.0%~101%,相对标准偏差小于11.2%。结果表明,该方法灵敏、高效、抗干扰力强,适用于饲料中的18种喹诺酮类药物的测定。     

液相色谱-串联质谱法检测猪肉中20种违禁药物残留的研究

建立了猪肉中违禁药物（糖皮质激素、性激素、β2-肾上腺素受体激动剂、玉米赤霉烯酮4类）同时测定的高效液相色谱-串联质谱方法。试样经盐酸水解,乙酸乙酯提取,低温冷冻去除脂类,亲水亲脂平衡固相萃取柱净化。采用C18反相色谱柱分离,以乙腈+水为流动相梯度洗脱,分别在电喷雾离子源正、负离子模式下以多反应监测模式（MRM）分段扫描同时检测,基质匹配内标法定量。结果表明,20种违禁药物在相应的浓度范围内线性良好,相关系数均大于0.99;该方法在猪肉中的检测限（LOD,S/N=3）和定量限（LOQ,S/N=10）分别为0.5、1.0 μg/kg。在0.5~10 μg/kg添加浓度水平下,平均回收率为63.9%~117%,批内变异系数1.9%~9.1%,批间变异系数4.9%~13.1%。该方法简单、快速、准确,适用于猪肉中多类违禁药物的残留检测。     

高效液相色谱-串联质谱法同时检测牛乳中11种农药残留量

采用高效液相色谱-串联质谱仪,建立一种可以同时检测牛乳中多种农药残留的分析方法。样品经乙腈提取,氯化钠、硫酸镁分层,经过2 次提取后,用C18固相萃取柱净化,流出液旋转蒸发至干后用乙腈复溶后上机测定。采用C18色谱柱进行分离,以5 mmol/L乙酸铵（含0.1%甲酸）-甲醇为流动相进行梯度洗脱,电喷雾离子化模式在多反应监测模式下测定。结果表明：啶虫脒、涕灭威、噻虫胺、甲胺磷、氟酰脲、苯丁锡、螺螨酯、苯醚甲环唑、噻草酮、氰氟虫腙及二甲四氯11 种农药在质量浓度0～100 ng/mL范围内线性良好,相关系数（R2）均大于0.995 0;对不含农药残留的牛乳样品进行3 个添加水平（1、2、4 μg/L）的测定,11 种农药的平均加标回收率为40.2%～99.2%,相对标准偏差均小于18.9%,方法检出限为1.00 μg/L;该方法可以快速、灵敏测定牛乳中11 种 农药残留量。     

测定鸡肉中利巴韦林残留的固相萃取-UPLC-MS/MS法研究

为建立鸡肉中违禁药物利巴韦林残留的固相萃取-液相色谱串联质谱测定方法,将鸡肉样品经酶解和0.5%甲酸水溶液提取,乙腈沉淀蛋白组织,HLB柱串联PBA柱固相萃取净化,超高效液相色谱-串联质谱法测定,稳定同位素内标法进行定量。结果显示,利巴韦林在5~100g/kg范围内呈良好的线性关系,不同浓度的精密度<20%,回收率在80%~120%之间。所建立的方法适合于鸡肉样品中利巴韦林残留的测定。     

分散固相萃取-高效液相色谱-串联质谱法测定水产品中19种喹诺酮类兽药残留

建立了高效液相色谱-电喷雾串联质谱联用测定水产品中19种喹诺酮类兽药残留的方法。采用酸化乙腈溶液进行提取,用固相填料进行分散固相萃取净化。以甲醇和0.1%甲酸溶液作为流动相,C18作为分析色谱柱,采用梯度洗脱方式进行液相色谱分离,选择离子反应监测模式检测19种喹诺酮类药物,内标方法定量。在2.0~100.0μg/L范围内,19种喹诺酮类药物的线性相关系数均大于0.99。通过添加回收试验,方法的定量限（S/N=10）为1.0μg/kg,3个添加水平中,小龙虾的回收率为70.5%~112.6%,相对标准偏差为3.5%~8.9%,鮰鱼的回收率为70.2%~113.8%,相对标准偏差为4.5%~8.9%。     

超高效液相色谱质谱联用测定饲料、牛乳及乳制品中双氰胺

建立超高效液相色谱质谱联用法检测饲料、牛乳及乳制品中双氰胺的方法.研究适用于检测饲料、牛乳及乳制品的前处理方法,并对色谱柱进行了选择.样品经乙腈提取、C18固相萃取填料净化后,低温冷冻离心除掉杂质,含0.1％甲酸的乙腈溶液和含0.1％甲酸的10 mmol/L甲酸铵水溶液梯度洗脱,通过Acquity BEH Amide色谱柱分离,电喷雾正离子多反应监测模式进行检测.结果表明:该方法在1～1 000 μg/L范围内线性良好,相关系数r大于0.995,饲料定量限最高40 μg/kg.不同添加质量浓度的回收率为80.5％～108.4％,相对标准偏差小于7.0％.该方法具有简单方便、检测周期短,适用于饲料、牛乳及乳制品检测等特点.     

超高效液相色谱-串联质谱法测定乳制品中季铵盐类化合物残留

建立牛乳、酸乳和乳粉3 种基质中超高效液相色谱-串联质谱同时检测4 种季铵盐类化合物残留的检测方法。用甲醇进行提取,经混合型弱阳离子交换反相吸附剂（WCX）固相萃取柱净化,2%甲酸甲醇溶液洗脱,氮吹后复溶,采用电喷雾正离子源、多反应监测模式进行检测。结果表明：牛乳、酸乳和乳粉中十二烷基三甲基溴化铵、十六烷基二甲基苄基氯化铵、十四烷基二甲基苄基氯化胺和二癸基二甲基氯化铵的定量限均为10 μg/kg;季铵盐类化合物添加量为10～200 μg/kg时,回收率为81.4%～105.6%,相对标准偏差为0.97%～     

PRIME HLB固相萃取/超高效液相色谱-串联质谱法测定乳制品中头孢菌素类药物残留

建立牛乳、酸乳和乳粉3 种基质乳制品中采用超高效液相色谱-串联质谱（ultra performance liquid chromatography-tandem mass spectrometry,UPLC-MS/MS）同时检测4 种头孢菌素类药物残留的方法。以5%甲酸乙腈溶液进行提取,经Oasis PRIME HLB固相萃取柱净化,氮吹后复溶,采用电喷雾离子源正离子模式及多反应监测模式进行检测。结果表明：牛乳和酸乳中头孢氨苄、头孢匹林、头孢洛宁和头孢喹肟的定量限为4 μg/kg,乳粉中为32 μg/kg     

粤西某市液态奶中壬基酚的污染调查

[目的]了解液态奶中壬基酚的污染水平和健康风险,为食品中壬基酚的标准测定和风险管理提供参考。[方法]从各大市场随机抽取液态奶,采用超高效液相色谱-质谱联用法测定壬基酚含量。[结果]共检测销售量较高的巴氏杀菌乳和UHT灭菌乳两类液态奶,共100 件样品,壬基酚检出率为80.00%,平均检测值为82.43 μg/kg。其中,巴氏杀菌乳中壬基酚平均检测值较高,为87.06 μg/kg。壬基酚的膳食暴露风险处于可接受范围之内。[结论]分析100 件市售液态奶中壬基酚的检测结果,对市售液态奶中壬基酚的安全性进行了风险分析,结果显示市场上液态奶相对比较安全,对人体健康存在较低风险。     

奶牛生产性能测定数据在牧场中的应用

[目的]奶牛生产性能测定（DHI）是用来管理奶牛生产的一项综合性技术,通过对DHI数据进行整理分析,可以指导牛场健康计划、改进日粮配方,加快奶牛遗传改良,提高奶牛育种水平。[方法]对广东省某奶牛场2022年1—12月14 024 条DHI数据进行统计,分析该牧场牛群结构、胎次、乳成分、体细胞数等指标,并根据数据提出改进措施。[结果]该牧场12 个月的平均胎次2.34 胎,日均产奶量为32.03 kg,高峰奶平均为39.6 kg,高峰奶日平均为80.17 天,305 天产奶量平均为9 641.55 kg,乳脂率平均为4.52%,乳蛋白率平均为3.16%,脂蛋比平均为1.44,体细胞数平均为33.3 万个/mL,尿素氮平均为10.9 mg/dL,泌乳天数平均为176.42 天。[结论]该牧场3 胎次以上牛只所占比例偏低,牛群结构不合理,体细胞数较高,尿素氮含量不稳定。应优化牛群结构,加强环境整治、乳房炎健康监测,同时调整日粮结构。     

Effects of pistachio by‐products on digestibility,milk production,milk fatty acid profile and blood metabolites in Saanen dairy goats

The objective of this study was to investigate the effects of pistachio by‐products (PBP) on nutrient digestibility, blood metabolites and milk fatty acid (FA) profile in Saanen dairy goats. Nine multiparous lactating Saanen goats (on day 90 post‐partum, 45 ± 2/kg BW) were randomly assigned to a 3 × 3 Latin square design with three treatment diets: 1) control diet (alfalfa hay based), 2) 32% PBP and 3) 32% PBP + polyethylene glycol (PEG‐4000; 1 g/kg dry matter). Each period lasted 21 days, including 14 day for treatment adaptation and 7 day for data collection. Pistachio by‐products significantly decreased (p < 0.01) crude protein (CP) digestibility compared with the control diet (64.4% vs. 58.7%), but PEG addition did not differ for CP digestibility of goats fed 32% PBP + PEG and those fed the two other diets. The digestibility of NDF tended (p = 0.06) to decrease for goats fed PBP compared with those fed the control diet. Yields of milk and 4% fat‐corrected milk were not affected by dietary treatments. Compared with the control diet, PBP supplementation appreciably changed the proportions of almost all the milk FA measured; the main effects were decreases (p < 0.01) in FA from 8:0 to 16:0 and increases (p < 0.01) proportions of cis‐9, trans‐11 18:2 and trans‐11 18:1, monounsaturated FA, polyunsaturated FA and long‐chain FA. The saturated FA, short‐chain FA and medium‐chain FA proportions were lower (p < 0.01) in goats fed the two PBP supplemented diet than in those fed the control diet and PEG addition led to intermediate proportions of saturated FA, unsaturated and monounsaturated FA. Inclusion of PBP in the diet decreased (p < 0.01) plasma concentrations of glucose and urea nitrogen compared with the control diet. It was concluded that PBP can be used as forage in the diet of dairy goats without interfering with milk yield. Inclusion of 32% PBP in the diet of dairy goats had beneficial effects on milk FA profile but PEG addition to PBP did not contribute to enhance further milk FA profile.     

非洲奶业发展现状及中非合作潜力研究

奶业是非洲居民重要的收入和就业来源,是重要的农业产业。2018年,非洲奶业生产总值171.22 亿美元,占畜牧业总产值的24.0%;奶牛存栏6 752.49 万头,主要集中在东非、北非和西非地区,养殖方式以散养为主,平均存栏仅3 头,部分品种仍以役用为主,牛奶生产仅是副产品,平均单产512.8 kg/头·年,年生鲜乳产量3 462.85 万t;埃及、肯尼亚和南非是主要的乳制品加工国家,加工量占非洲生鲜乳产量的近30%;2019年乳制品消费量折合生鲜乳为5 468.21 万t,鲜奶是最主要的消费品类,占60%以上,其次是奶粉和奶酪,分别占消费量（折合生鲜乳）的16%和15%,人均消费量有所下降,2019年为41.74 kg/人·年;乳制品贸易长期处于净进口趋势,2018年进口量198.72 万t,进口额48.57 亿美元,北非、西非和东非是主要进口地区。非洲奶牛养殖提升空间巨大,乳制品加工前景广阔,乳制品消费增长空间巨大,中国进一步加强与非洲奶业在奶牛养殖、乳制品加工以及奶业贸易等方面的国际合作,推动奶业走出去。     

全株甘蔗的奶牛瘤胃降解特性及其替代奶牛饲粮苜蓿、燕麦草及精料的应用研究

本试验旨在探究全株甘蔗的奶牛瘤胃降解特性及其替代奶牛饲粮中苜蓿、燕麦草及精料对奶牛瘤胃发酵、营养物质表观消化率、血液生化指标及生产性能的影响,为其替代奶牛饲粮中价格日益攀升的苜蓿和精饲料,并用作奶牛粗饲料资源开辟新途径。试验一采用半体内试验即瘤胃尼龙袋技术,探究了全株甘蔗、国产羊草与国产苜蓿各营养成分的瘤胃降解特性;试验二采用重复3×3拉丁方试验设计,选择体重、胎次、泌乳天数和产奶量相近并装有永久瘤胃瘘管的荷斯坦奶牛进行消化试验,探究全株甘蔗替代饲粮25%或50%的美国进口苜蓿对奶牛营养物质消化率、瘤胃发酵特性和血液生化指标的影响;试验三选取60头胎次、产奶量和泌乳天数相近的荷斯坦奶牛进行生产试验,探究了全株甘蔗分别替代饲粮30%苜蓿干草、50%燕麦草或10%精料对奶牛生产性能、血液生化指标和牧场经济效益的影响。结果发现：1）全株甘蔗干物质（DM）和酸性洗涤纤维（ADF）的有效降解率显著高于国产羊草（P<0.05）,中性洗涤纤维（NDF）和有机物（OM）的有效降解率显著高于国产羊草和国产苜蓿（P<0.05）。2）用全株甘蔗替代饲粮25%或50%美国进口苜蓿对奶牛瘤胃pH、氨态氮（NH₃-N）（除25%组4 h外）和挥发性脂肪酸（VFA）含量无显著影响;对奶牛干物质采食量（DMI）及饲粮DM、粗蛋白质（CP）、OM和ADF消化率无显著影响,而全株甘蔗替代饲粮50%美国进口苜蓿组的NDF消化率显著升高（P<0.05）;全株甘蔗替代饲粮中50%美国进口苜蓿组2和8 h血清尿素氮含量显著低于25%组和对照组（P<0.05）,且各处理组不同时间点血液β-羟丁酸含量、瘤胃各VFA和总VFA含量均无显著差异。3）用全株甘蔗替代高产奶牛饲粮中50%燕麦草、30%苜蓿干草或10%精料对奶牛血液中的葡萄糖、尿素氮、β-羟丁酸和非酯化脂肪酸（NEFA）等含量及产奶量均无显著影响,且综合产奶量和饲料成本两方面的因素,各替代组分别比对照组每头奶牛的经济效益增加3.28、7.48和1.62元·d^-1。由此可知,全株甘蔗是一种可供奶牛食用的消化率较高的优质粗饲料,且用其替代饲粮中的25%或50%美国进口苜蓿不影响奶牛的瘤胃发酵特性和营养物质表观消化率;用其替代30%苜蓿干草、50%燕麦草或10%精料不会影响奶牛的血液生化指标及生产性能,还会提高牧场的经济效益。     

The Rumen Degradation Characteristics of Whole Sugarcane for Dairy Cows and Its Application in Substituting Alfalfa,Oat Hay and Concentrate in Dairy Cows' Diets

The purpose of this experiment was to investigate the rumen degradation characteristics of whole sugarcane of dairy cows and its effects of using it replacing alfalfa, oat hay and concentrates in dairy cows' diet on the rumen fermentation, nutrient apparent digestibility, blood biochemical indexes and production performance of dairy cows, in order to open up new ways to replace the increasing prices feedstuff such as alfalfa, oat hay and concentrate in dairy cows' diets with whole sugarcane. In experiment one, the in-situ test, namely the rumen nylon bag test was used to investigate the rumen degradation characteristics of various nutrients of whole sugarcane, leymus chinensis and alfalfa. Experiment two was in vivo test,repeat 3 ⅹ 3 Latin square design was conducted and Holstein dairy cows with similar body weight, parities and milk yield and permanent rumen fistula were chosen to investigate the effect of using whole sugarcane replacing 25% or 50% of imported alfalfa from the Unites States in dairy cows' diet on nutrient digestibility, rumen fermentation characteristics and blood biochemical indexes of dairy cows. In experiment three, 60 Holstein dairy cows with similar parity, milk yield and milk in lactation were selected to perform production test, which aimed to explore the effects of using whole sugarcane replacing 30% alfalfa hay, 50% oat hay or 10% concentrate on the production performance, blood biochemical indexes of dairy cows and the economic benefits of dairy farms. The results showed that：1) The effective degradation rates of dry matter (DM) and acid detergent fiber (ADF) of whole sugarcane were significantly higher than leymus chinensis (P<0.05), and the effective degradation rates of neutral detergent fiber (NDF) and organic matter (OM) were significantly higher than leymus chinensis and alfalfa (P<0.05). 2) There was no significant effect on rumen pH, NH₃-N (except 25% group at the 4 h time point) and volatile fatty acid (VFA) concentrations of dairy cows when using 25% and 50% whole sugarcane to replace imported alfalfa from the Unites States in the diet. There was also no significant effect on DMI and digestibility of DM, CP, OM and ADF, while the digestibility of NDF in the 50% group was significantly increased (P<0.05). In 50% group, the content of serum urea nitrogen in 2 and 8 h was significantly lower than 25% group and control group (P<0.05) and there was no significant difference in the blood content of β-hydroxybutyric acid, rumen VFA and total VFA in each group at different time points. 3) After using 50%, 30% and 10% of whole sugarcane to replace oat hay, alfalfa hay and concentrate, respectively, no significant difference was detected in blood glucose, urea nitrogen, β-hydroxybutyric acid, the esterification of fatty acid (NEFA), and milk yield. Besides, combined with milk yield and feed cost, the economic benefits of each cow in the substitution groups increased by 3.28, 7.48 and 1.62 yuan per day. respectively, compared with control group. It can be seen that the whole sugarcane is a kind of high-quality roughage that can be used by dairy cows with high digestibility, and using it to replace 25% or 50% of imported alfalfa from the Unites States in dairy cows' diet does not affect the rumen fermentation characteristics and rumen apparent digestibility of nutrients of dairy cows. And using whole sugarcane replacing 30% alfalfa hay, 50% oat hay or 10% concentrate will not affect the blood biochemical indicators and production performance of dairy cows, and will also increase the economic benefits of the dairy farm.     

Iodine concentration in the blood serum of milk cows from Saxony as well as in cows' milk and milk products (baby food)

Within the framework of investigations into the metabolism of Saxon dairy-cows, more than 3300 analyses of blood serum total iodine concentrations have been carried out between 1997 and 2003. The total iodine concentration proved as suitable parameter for the recognition of the iodine supply situation of the milk cows. While to first two years 28,5 % of the samples were rated below the recommended minimum level (0,04 mg/l), thus indicating deficiencies, the total iodine concentration then rose demonstrably, even indicating an oversupply in some herds (> or = 0,20 mg/l). The iodine concentration in 117 independently tested milk samples (official food monitoring) confirmed this situation. An adequate iodine supplementation in feedstuffs is of great significance for the bovine metabolism as well as for the iodine concentrations in milk and therefore the iodine intake of the population. Of the negative consequences of an uncritically excessive iodine supplement particularly for high milk-yield cows one warns. This can lead to precariously high iodine concentrations in milk and dairy products. Further tests of blood total iodine levels in dairy herds on selective animals as well as analysis