三聚氰胺联合三聚氰酸对攻毒大肠杆菌小鼠抵抗力的影响

试验旨在研究三聚氰胺及其同系物对机体免疫力产生的可能影响,为完善该类污染物的毒理学评价资料提供依据。试验将雄性KM小鼠144只随机分为8组,分别为空白对照组、大肠杆菌阳性对照组,试验组包括三聚氰胺高、中、低剂量组(50 mg/kg、10 mg/kg、2mg/kg)、三聚氰胺与三聚氰酸联合高、中、低(25+25mg/kg、5+5mg/kg、1+1mg/kg)剂量组,试验组隔天灌胃15d后,腹腔注射大肠杆菌,48h后检测小鼠脾脏B淋巴细胞增殖率、血清溶血素光密度值和迟发性变态免疫反应指标。研究结果表明,与对照组相比,当三聚氰胺和三聚氰酸攻毒剂量达到25+25mg/kg时,B淋巴细胞转化能力下降(0.01P0.05),血清溶血素吸光度值下降(P0.01),当攻毒剂量达到三聚氰胺50mg/kg、三聚氰胺和三聚氰酸剂量25+25mg/kg、5+5mg/kg时,小鼠足趾增厚度减小(P0.01),提示三聚氰胺和三聚氰酸能够降低小鼠对大肠杆菌的抵抗能力。     

三聚氰胺与三聚氰酸联用诱导禽肝脏氧化损伤的研究

为了研究三聚氰胺与三聚氰酸联合导致蛋雏鸡肝脏氧化损伤,试验分别在基础饲料中添加30 mg/kg三聚氰胺+10 mg/kg三聚氰酸(低剂量组)和50 mg/kg三聚氰胺+16.7 mg/kg三聚氰酸(高剂量组),饲喂8日龄蛋雏鸡,在第7,14,21,28,35,42天宰杀鸡群(每次每组8只),取肝脏提取蛋白,检测蛋白浓度、总超氧化物歧化酶(T-SOD)活性、丙二醛(MDA)含量。结果表明:三聚氰胺与三聚氰酸联合作用后第1~5周内,试验组T-SOD活性差异不显著(P0.05);第6周试验组TSOD活性低于对照组,低剂量组差异极显著(P0.01),高剂量组差异显著(P0.05)。第1~6周试验组MDA含量与对照组相比差异不显著(P0.05)。说明三聚氰胺与三聚氰酸联用可显著增加肝细胞线粒体损伤,但对法氏囊组织细胞生物膜损伤不明显。     

泌乳奶牛单次口服三聚氰胺由饲料向牛奶及由牛奶向干酪和乳清中的转化

本试验旨在研究口服1次三聚氰胺,其由饲料向牛奶中排出形式,以及随后由牛奶向干酪和乳清中的转化。同时对于三聚氰酸的转化进行了研究。24头泌乳荷斯坦奶牛随机分为4个处理,设定为D1、D2、D3和D4组,各组奶牛仅饲喂1次三聚氰胺,饲喂量分别为0.05、0.50、5.00和50.00 g/d。试验第1、2、3、4、5、7天采集牛奶样品测定其中三聚氰胺和三聚氰酸含量。摄入三聚氰胺后第2次采集的奶样用于实验室条件下制作干酪。三聚氰胺和三聚氰酸采用固相萃取柱萃取,并利用液相色谱/串联质谱法进行测定。处理后第6至18 h三聚氰胺浓度最高并呈对数(线性和二次)上升,范围在0.019～35.105 mg/kg之间。三聚氰胺摄入30 h后,60%以上的三聚氰胺转移至乳中。D1组奶牛饲喂后第5天其乳中三聚氰胺含量低于检出限(检出限0.002mg/kg),而D2、D3和D4组奶牛饲喂后7 d乳中三聚氰胺含量低于检出限。血尿氮不受摄入三聚氰胺影响。制作干酪过程中,三聚氰胺主要转移至乳清中。奶牛乳中、干酪或乳清中均未检出三聚氰酸。当奶牛每天摄入0.50 g三聚氰胺时,其排出方式为乳和乳清,可能引起人们对健康的关注。但只有摄入量为5和50 g/d时,干酪中三聚氰胺含量超过欧盟规定限量。本研究结果说明,三聚氰胺污染乳和乳制品也许既与直接污染有关,同时也与动物饲料掺假有关。     

三聚氰胺对肉鸡的亚慢性毒性研究

试验旨在研究三聚氰胺对肉鸡的亚慢性毒性。选取120只1日龄健康AA肉鸡,随机分成5组,第1组为对照组,第2~5组为试验组,分别饲喂含三聚氰胺0、40、120、360和1 080 mg/kg的饲料,试验期为60 d。结果表明,肉鸡摄入含三聚氰胺360 mg/kg和1 080 mg/kg的饲料,出现明显的中毒症状和死亡,肉鸡料重比、平均日增重极显著低于对照组(P0.01);血浆丙氨酸氨基转氨酶(ALT)和天门冬氨酸氨基转氨酶(AST)活性、血浆肌酐、尿酸含量以及肝脏和肾脏指数显著高于对照组(P0.05)。肉鸡摄入含三聚氰胺40 mg/kg和120 mg/kg的饲料,其生产性能、血液生化指标及脏器指数与对照组无明显差异(P0.05)。由此可见,肉鸡摄入饲料中三聚氰胺含量高于360 mg/kg可发生三聚氰胺中毒,中毒靶器官是肝脏和肾脏;饲料中三聚氰胺对肉鸡的无可见有害作用水平为120 mg/kg。     

大鼠体内三聚氰胺及其代谢物双波长HPLC检测方法的建立

建立双波长高效液相色谱法同时检测不同给药剂量组大鼠体内三聚氰胺、三聚氰酸和尿酸含量的方法。采用C18色谱柱,流动相为0.5mmol/L磷酸盐(pH 7.4)-甲醇(95∶5,V/V),流速1.0mL/min,检测波长三聚氰胺和三聚氰酸为213nm,尿酸为285nm,进样量10μL,柱温25℃。样品用0.6mol/L高氯酸沉淀蛋白质。结果表明,三聚氰胺、三聚氰酸、尿酸分别在0.10~1.00×10~2、0.50~1.00×10~2、0.20~1.00×10~2μg/mL范围内线性关系良好(r=0.999 9),最低检出限分别为2.50×10~(-2)、7.50×10~(-2)、3.00×10~(-2)μg/mL,平均回收率在90.99%~96.09%之间,相对标准偏差在0.84%~1.40%之间。该方法操作简便、灵敏度高、结果准确可靠,可用于动物体内三聚氰胺、三聚氰酸及尿酸同时检测和分析。     

三聚氰胺等4种物质的毒性比较研究

试验旨在通过细胞毒性试验、急性毒性试验对三聚氰胺及其类似物的毒性进行了初步研究。结果表明,三聚氰胺、三聚氰酸、双氰胺、单氰胺的半数抑制浓度（IC₅₀）分别为10.11、3.17、22.56、0.305 mg/ml,而三聚氰胺、三聚氰酸、双氰胺的半数致死量（LD₅₀）均大于5000 mg/kg,单氰胺的半数致死量（LD₅₀）小于500 mg/kg。表明三聚氰胺、三聚氰酸、双氰胺为微毒或基本无毒,单氰胺为高毒。     

原料乳及乳制品中三聚氰胺/三聚氰酸对动物和人类危害的研究

正三聚氰胺变成社会热点话题始于2007年美国宠物饲料致死猫犬事件和2008年三鹿奶粉事件。在回收的宠物食品、死亡动物的尿液结晶和肾脏细胞中都发现有三聚氰胺。近年来,国内外对三聚氰胺的研究取得了很大的进展,本文综述了饲料乳制品中三聚氰胺的代谢和中毒机制等方面的研究进展。三聚氰胺(Melamine)是一种三嗪类含氮杂环有机化合物,又称三胺、2,4,6-三氨基-1,3,5-三嗪、蜜胺、三聚氰酰胺、氰脲三酰胺,有3种同系物:三聚氰酸     

饲料中三聚氰胺ELISA检测方法的优化初探

饲料中三聚氰胺的检测方法有ELISA法、液相法、GC／MS法3种。ELISA法操作简便,检测速度快,但假阳性和假阴性高;液相法的假阳性较少．但分析速度慢．而且色谱峰的分离度受流动相的影响较为明显．导致定性与定量困难。GC／MS法的分析速度与液相法相当．其优点是准确率高,但仪器昂贵,检测成本高．过程烦琐。面对大批量样品检测．利用液相法和GC/MS法．想在短时间内得到检测结果,显然很困难。那么．能不能利用ELISA法。既能提高检测速度又能避免大量假阳性的出现呢？我们分别以BRAXIS试剂盒方法．使用其内制曲线和经确证不含三聚氰胺和三聚氰胺添加量为2mg／kg的浓缩饲料和配合饲料为阳性对照．以液相法的2mg／kg检测限为控制线,同时对100批次饲料产品进行了检测。并将筛选的三聚氰胺阳性样品进行GC,MS法确证。通过比较．探讨以类似待测样品成分、并经确证不含三聚氰胺的三聚氰胺添加样为阳性对照．以液相法的2mg／kg检测限为控制线．对样品中三聚氰胺快速测定的可行性。     

铜梁县畜牧兽医局严厉查处重庆市翰丰饲料有限公司涉嫌违法使用禁用饲料添加剂生产饲料行为

重庆市翰丰饲料有限公司,于08年12月25日在重庆市兽药饲料检测所三聚氰胺专项监测行动抽样检测中,其产品羽毛粉被检测出三聚氰胺含量为21.8 mg/kg,超过了国家规定限定值(《2 mg/kg).     

气相色谱-质谱法同时测定饲料中三聚氰胺和盐酸克伦特罗

建立了同时测定饲料中三聚氰胺和盐酸克伦特罗的固相萃取-气相色谱-质谱分析方法。饲料样品用乙腈和50 mmol/L稀盐酸提取,然后用乙酸乙酯液液萃取净化,水相经PCX固相萃取小柱净化后用含1%三甲基氯硅烷的BSTFA衍生,采用选择离子模式进行测定,三聚氰胺衍生物选择离子为213,285,327,342,盐酸克伦特罗衍生物选择离子为86,212,262,277,外标法定量,三聚氰胺和盐酸克伦特罗检出限分别为0.6μg/kg和2.4μg/kg。在添加浓度10～200μg/kg范围内,饲料中三聚氰胺和盐酸克伦特罗的回收率分别为81.3%～92.0%和70.8%～82.2%,批内RSD分别为2.6%～4.5%和2.7%～5.2%,批间RSD分别为3.8%～7.0%和5.4%～6.1%。衍生物的峰面积与样品浓度在0.01～0.50mg/L范围内呈良好的线性关系,线性回归系数均大于0.999。     

三聚氰胺及其三聚氰酸混合物对小鼠肝脏的损伤及损伤机理

试验采取检测各攻毒组小鼠肝脏受损情况、肝脏细胞凋亡及相关凋亡机制。结果显示,三聚氰胺及其三聚氰酸混合物对小鼠肝脏的损伤随着混合物剂量的上升呈量效关系,剂量越高损伤作用越严重,而三聚氰胺单独组和三聚氰酸单独组对小鼠肝脏无明显损伤作用。三聚氰胺与三聚氰酸混合物主要是通过诱导小鼠肝脏细胞凋亡而致肝组织损伤,Bax和caspase-3基因参与了三聚氰胺和三聚氰酸诱导小鼠肝细胞凋亡的调控。     

三聚氰胺及其与三聚氰酸联合毒性的研究进展

中国"三鹿奶粉事件"使得三聚氰胺受到国内外的广泛关注,近年来陆续报道了关于三聚氰胺及其与三聚氰酸的联合作用对人、鼠、鸡、猪等的毒性。作者就三聚氰胺和三聚氰酸的理化性质及其对人、鼠、鸡等的影响,以及三聚氰胺所导致的结石结构进行综述,为进一步研究提供参考。     

Assessment of melamine and cyanuric acid toxicity in cats.

The major pet food recall associated with acute renal failure in dogs and cats focused initially on melamine as the suspect toxicant. In the course of the investigation, cyanuric acid was identified in addition to melamine in the offending food. The purpose of this study was to characterize the toxicity potential of melamine, cyanuric acid, and a combination of melamine and cyanuric acid in cats. In this pilot study, melamine was added to the diet of 2 cats at 0.5% and 1%, respectively. Cyanuric acid was added to the diet of 1 cat at increasing doses of 0.2%, 0.5%, and 1% over the course of 10 days. Melamine and cyanuric acid were administered together at 0%, 0.2%, 0.5%, and 1% to 1 cat per dose group. No effect on renal function was observed in cats fed with melamine or cyanuric acid alone. Cats dosed with a combination were euthanized at 48 hours after dosing because of acute renal failure. Urine and touch impressions of kidneys from all cats dosed with the combination revealed the presence of fan-shaped, birefringent crystals. Histopathologic findings were limited to the kidneys and included crystals primarily within tubules of the distal nephron, severe renal interstitial edema, and hemorrhage at the corticomedullary junction. The kidneys contained estimated melamine concentrations of 496 to 734 mg/kg wet weight and estimated cyanuric acid concentrations of 487 to 690 mg/kg wet weight. The results demonstrate that the combination of melamine and cyanuric acid is responsible for acute renal failure in cats.     

Residue depletion of melamine and cyanuric acid in catfish and rainbow trout following oral administration

Reimschuessel, R., Evans, E., Andersen, W. C., Turnipseed, S. B., Karbiwnyk, C. M., Mayer, T. D., Nochetto, C., Rummel, N. G., Gieseker, C. M. Residue depletion of melamine and cyanuric acid in catfish and rainbow trout following oral administration. J. vet. Pharmacol. Therap. 33 , 172–182. The intentional addition of triazines such as melamine to animal feeds and the lack of information about residue accumulation in food animals caused global concerns for food safety during 2007 and 2008. We report the results of a good laboratory practices (GLP) study to determine melamine and cyanuric acid residues in catfish and trout filets harvested at 1, 3, 7, 14, 28, and 42 days after a single oral dose of 20 mg/kg body weight of melamine, cyanuric acid, or melamine and cyanuric acid together. Peak melamine concentrations were 12.73 mg/kg (ppm) in catfish (mean = 9.98), 12.26 mg/kg in trout (mean = 7.89) on day 1. Within 7 days (catfish) or 14 days (trout) residues were <2.5 mg/kg, a level in foods accepted by many risk assessors worldwide to be unlikely to pose health risks to consumers. Peak cyanuric acid residues also occurred on day 1, 0.68 mg/kg in catfish (mean = 0.46), 2.59 mg/kg in trout (mean = 0.86). Cyanuric acid muscle residues were <2.5 mg/kg by day 3. The half‐lives for melamine and cyanuric acid ranged between 1 and 4 days. Renal crystals formed in fish given both melamine and cyanuric acid, persisting for weeks after the single dose.     

Evaluation of the renal effects of experimental feeding of melamine and cyanuric acid to fish and pigs

OBJECTIVE: To determine whether renal crystals can be experimentally induced in animals fed melamine or the related triazine compound cyanuric acid, separately or in combination, and to compare experimentally induced crystals with those from a cat with triazine-related renal failure. ANIMALS: 75 fish (21 tilapia, 24 rainbow trout, 15 channel catfish, and 15 Atlantic salmon), 4 pigs, and 1 cat that was euthanatized because of renal failure. PROCEDURES: Fish and pigs were fed a target dosage of melamine (400 mg/kg), cyanuric acid (400 mg/kg), or melamine and cyanuric acid (400 mg of each compound/kg) daily for 3 days and were euthanatized 1, 3, 6, 10, or 14 days after administration ceased. Fresh, frozen, and formalin-fixed kidneys were examined for crystals. Edible tissues were collected for residue analysis. Crystals were examined for composition via Raman spectroscopy and hydrophilic-interaction liquid chromatography-tandem mass spectrometry. RESULTS: All animals fed the combination of melamine and cyanuric acid developed goldbrown renal crystals arranged in radial spheres (spherulites), similar to those detected in the cat. Spectral analyses of crystals from the cat, pigs, and fish were consistent with melamine-cyanurate complex crystals. Melamine and cyanuric acid residues were identified in edible tissues of fish. CONCLUSIONS AND CLINICAL RELEVANCE: Although melamine and cyanuric acid appeared to have low toxicity when administered separately, they induced extensive renal crystal formation when administered together. The subsequent renal failure may be similar to acute uric acid nephropathy in humans, in which crystal spherulites obstruct renal tubules.     

三聚氰胺及其同系物的毒理学研究进展

三聚氰胺有3种同系物,分别为三聚氰酸、三聚氰酸一酰胺和三聚氰酸二酰胺,均属于三嗪类含氮杂环有机化合物。"三聚氰胺"这个原本对一般人而言很陌生的物质,由于其带来的危害已经引起了全世界的重视。研究者们针对该类化合物的毒性进行了大量研究,并且已取得了较大进展,三聚氰胺及其同系物的肝脏、肾脏、神经细胞等毒性被陆续揭示出来。由于环境、包装及人为因素的影响,三聚氰胺及其同系物对人和动物的危害不容忽视,论文以近年来最新资料为基础,对三聚氰胺及其同系物的毒理学研究概况作以综述,以期为该类化合物的毒理学评价和监测提供参考。     

Depletion of melamine and cyanuric acid in kidney of catfish Ictalurus punctatus and trout Oncorhynchus mykiss

A risk assessment conducted in 2007 identified significant knowledge gaps about tissue residues of melamine and related triazine analogs such as cyanuric acid in animals that had eaten contaminated food. The USFDA subsequently designed studies to determine residue levels in muscle, serum, and kidneys of catfish and trout given a single gavage dose of 20 mg/kg body weight (BW) of melamine, cyanuric acid, or 20 mg/kg BW of both compounds simultaneously. Renal triazines were determined by LC‐MS/MS at postdose days 1, 3, 7, 14, 28 (and day 42 for trout). When dosed individually, melamine and cyanuric acid kidney residues depleted much faster than those in fish given both compounds together. Combined dose residue depletion was punctuated by extreme outliers due to the formation of persistent renal melamine cyanurate crystals.     

氯溴异氰尿酸及其复配药液对家蚕主要病原体的消毒效果试验

氯溴异氰尿酸是一种高效、广谱的内吸性杀菌剂。将氯溴异氰尿酸与磷酸三钠或碳酸钠复配成不同浓度药液,对家蚕主要病原体进行消毒试验。0.125 g/L氯溴异氰尿酸药液对白僵菌、黄曲霉菌可达到100%的消毒效果,但对家蚕核型多角体病毒(BmNPV)、家蚕质型多角体病毒(BmCPV)无消毒效果;在0.125 g/L氯溴异氰尿酸药液中添加10.0 g/L磷酸三钠或碳酸钠后,对BmNPV、BmCPV可达到100%的消毒效果。将磷酸三钠或碳酸钠添加到1.0 g/L氯溴异氰尿酸溶液中,对BmNPV、BmCPV具有100%消毒效果的最低添加浓度分别为1.0、0.5 g/L和2.0、1.0 g/L。氯溴异氰尿酸药液稳定,添加磷酸三钠或碳酸钠后的复配药液稳定性差,但添加磷酸三钠的稳定性优于添加碳酸钠的稳定性。综上初步认为,氯溴异氰尿酸与磷酸三钠混合的消毒药液可以应用于家蚕真菌病、病毒病主要病原的消毒,且药液宜现配现用。     

Clinicopathologic, histologic, and toxicologic findings in 70 cats inadvertently exposed to pet food contaminated with melamine and cyanuric acid

OBJECTIVE: To document clinicopathologic, histologic, and toxicologic findings in cats inadvertently exposed to pet food contaminated with melamine and cyanuric acid. DESIGN: Case series. ANIMALS: 70 cats from a single cattery inadvertently fed contaminated food that was the subject of a March 2007 recall. PROCEDURES: Clinical signs, clinicopathologic and histopathologic findings, and results of toxicologic analyses were recorded. RESULTS: Clinical signs were identified in 43 cats and included inappetence, vomiting, polyuria, polydipsia, and lethargy. Azotemia was documented in 38 of the 68 cats for which serum biochemical analyses were performed 7 to 11 days after consumption of the contaminated food. One cat died, and 13 were euthanized. Histologic examination of kidney specimens from 13 cats revealed intratubular crystalluria, tubular necrosis with regeneration, and subcapsular perivascular inflammation characterized by perivascular fibroplasia or fibrosis and inflammation with intravascular fibrin thrombi. Toxicologic analyses revealed melamine and cyanuric acid in samples of cat food, vomitus, urine, and kidneys. CONCLUSIONS AND CLINICAL RELEVANCE: In cats unintentionally fed pet food contaminated with melamine and cyanuric acid, the most consistent clinical and pathologic abnormalities were associated with the urinary tract, specifically tubular necrosis and crystalluria.     

Melamine residues in eggs of quails fed on diets containing different levels of melamine

1. An experiment was conducted to determine residual melamine concentrations in eggs of quail given diets containing different concentrations of melamine, and to estimate the time at which withdrawing melamine from the diet would result in undetectable concentrations in eggs. A total of 600 Japanese quails (Coturnix coturnix japonica) were randomly divided into 5 treatments, and given melamine at concentrations of 0, 2, 10, 50, and 100?mg/kg diet respectively for 30?d. From d 31 to 41, all quails were given a diet without melamine. Each diet was offered to 4 replicates (cages) of 30 quails each. On d 11, 13, 15, 17, 19, 21, 23, 25, 27, 29, 31, 33, 35, 37, 39, and 41, eggs were collected for the determination of melamine and cyanuric acid levels.

2. Throughout the 41?d experimental period, inclusion levels of melamine in the diets of quails had no significant effect on daily feed intake, egg production percentage, and feed efficiency. No detectable amount of cyanuric acid was found in all eggs. When the diets contained melamine at 2?mg/kg, the amounts of melamine in eggs were below the detection limit. During the entire 30?d exposure, the maximum melamine concentrations in eggs were 0·162, 0·998 and 1·784?mg/kg for the 10, 50 and 100?mg/kg treatment groups, respectively, which demonstrated a linear dose-response relationship.

3. Upon feeding a diet without melamine, the melamine concentration in eggs decreased rapidly. The time taken for the amounts of melamine to decline below the detection limit were 1, 5, and 5?d for quails fed on the diets containing melamine at 10, 50, and 100?mg/kg respectively.

4. Melamine is not metabolised into cyanuric acid in quails, and a positive relationship exists between the concentrations in feed and in eggs.