三聚氰胺在鸭蛋中的沉积和消除规律的研究

本试验旨在研究日粮中添加不同水平的三聚氰胺(melamine,MEL)在鸭蛋中的沉积和消除规律.选用体重为(1.66±0.16)kg和产蛋率为(75.15±3.29)%的19周龄健康金定产蛋鸭756只,随机分成7个处理,每个处理设6个重复,每个重复18只.7种试验日粮的MEL添加水平分别为:0、1、2、5、25、50和100 mg/kg.各处理分别连续饲喂含不同水平MEL的日粮21 d(沉积试验),随后改喂基础日粮21 d(消除试验),试验期共42 d.于沉积和消除试验的第1～11天、第13天、第15天、第17天和第21天分别测定鸭蛋可食部分中的MEL和三聚氰酸(cy-anuric acid,CYA)含量.结果表明,0～5 mg/kg的4个处理之间鸭蛋中MEL含量差异不显著(P>0.05),25～100 mg/kg的3个处理之间差异极显著(P<0.01),且均极显著高于0～5 mg/kg的4个处理(P<0.01);鸭蛋MEL含量(Y,mg/kg)与日粮MEL添加水平(X,mg/kg)的关系方程为:y=0.0121X+0.0165(R2=0.9994),MEL由日粮到鸭蛋中的生物富集系数为0.0121;通过鸭蛋排出的MEL(Y,mg/d)与蛋鸭摄人的MEL(X,mg/d)拟合的曲线为:Y=0.2618X+0.0947(R2=0.9999),MEL由蛋鸭到鸭蛋的母体转移系数为0.2618.日粮MEL添加水平越高,鸭蛋中的消除半衰期越短,完全消除需要的时间越长;5、25、50和100 mg/kg处理鸭蛋中的MEL含量(Y,mg/kg)随时间(X,d)消除方程分别为:Y=0.0802X-0.747(R2=0.7775)、Y=0.3268X-1.1608(R2=0.9871)、Y=0.5912X-1.3403(R2=0.9922)和Y=1.2004X-1.3956(R2=0.9883),根据上述方程计算各处理鸭蛋中MEL完全消除时间分别为3.48、7.81、9.31和14.61 d;鸭蛋中未检测到CYA.结果显示,MEL在产蛋鸭日粮中浓度越高,其鸭蛋中沉积最越大,消除时间越长.     

体外培养法研究三聚氰胺的降解规律及其对瘤胃发酵参数的影响

本试验采用体外培养法研究三聚氰胺(Melamine,MEL)对瘤胃发酵参数的影响。MEL的添加水平分别为0、2、10、50、250和1 250mg·L-1,培养时间分别为0、1、2、4、6、8、12、24和48h,测定了培养液中MEL的浓度变化,总挥发性脂肪酸(TVFA)、乙酸、丙酸、丁酸、戊酸、异丁酸、异戊酸含量和NH3-N浓度。结果表明:MEL在瘤胃液中培养48h没有被降解(P>0.05),添加MEL降低了干物质降解率(DMD)(P<0.05),提高了丁酸的摩尔比例(P<0.05),MEL为1 250mg·L-1时会降低丙酸摩尔比例(P<0.05),提高了乙∶丙酸比值(P<0.05)。MEL抑制瘤胃微生物生长,不能作为瘤胃微生物非蛋白氮来源。     

三聚氰胺对肉鸡毒性作用分析

本试验旨在通过研究三聚氰胺(MEL)对肉鸡生长性能、血清生化指标和肝肾病理学的影响,分析其对肉鸡的毒性作用.试验选用1 920只1日龄科宝肉仔鸡,随机分为6个处理,分别饲喂添加0、2、10、30、50和100 mg/kg MEL的饲粮,每个处理10个重复,每个重复32只肉鸡.试验期42 d.结果表明,饲粮中添加MEL对...     

三聚氰胺在肉鸡体内的消化代谢及其对饲粮养分利用率和流通速率的影响

本研究旨在通过2个试验探讨三聚氰胺(MEL)在肉鸡体内的消化代谢及其对饲粮养分利用率和流通速率的影响.试验1旨在考察MEL在肉鸡体内的表观排泄率和表现回肠消化率.选用240只1日龄健康的科宝雏鸡,设2个组,分别在饲粮中添加0和100 mg/kg MEL,每组6个重复,每个重复20只鸡,分别在15～21 d和36～42 ...     

褪黑素对羊生殖调控的研究进展

褪黑素(Melatonin,MEL/MLT/MT)是由松果体分泌的一种吲哚类激素,化学名称为N-乙酰-5-甲氧基色胺(N-ac-etyl-5-methoxytryptomine)国外在20世纪60年代就人工合成MEL,随后采用放免法、受体分析法、酶免法及分子生物学技术应用,使MLT的生理功能、受体分布、作用机制、生物合成及对生殖的调控机理等方面取得了较大的研究进展,MEL在畜牧业以及医学领域的应用也日益广泛.     

三聚氰胺和三聚氰酸对蛋鸡毒性效应的研究

本试验旨在探讨饲粮中单独添加三聚氰胺(melanmine,MEL)或与三聚氰酸(cyanuric acid,CYA)合用对蛋鸡健康的影响.将126只78周龄罗曼粉壳蛋鸡随机分为7个组,每组9个重复,每个重复2只鸡.组1为对照组,饲喂基础饲粮;组2～4分别饲喂在基础饲粮中添加MEL 5、15和30 mg/kg的饲粮,组5...     

关于上海华联制药厂甲氨蝶呤药物损害事件的思考

[编者按] 2007年,上海华联制药厂甲氨蝶呤药物损害事件曝光,国家药品监督管理局依法注销其多个产品批准文号,同时相关责任人已被公安机关刑事拘留,并将被依法追究刑事责任.该事件与2006年"齐二药"、"欣弗"事件一道,在医药界引起了轩然大波.     

饲粮中三聚氰胺对乳成分的影响及其在牛奶中的残留规律

本试验旨在研究饲粮中三聚氰胺对泌乳奶牛干物质采食量、产奶量和乳成分的影响,并探讨饲粮中三聚氰胺在牛奶中的残留规律。试验选择9头泌乳中期[泌乳日龄(DIM)为(160±21)d]的中国荷斯坦奶牛,随机分成3组,分别饲喂添加0.1%(MEL1组)、0.5%(MEL2组)和1.0%(MEL3组)三聚氰胺的饲粮(干物质基础)。试验期28 d。结果表明,饲粮添加三聚氰胺对奶牛干物质采食量、产奶量、乳脂、乳蛋白和乳糖含量无显著影响(P>0.05);但乳中尿素含量随着三聚氰胺添加量的增加显著升高(P<0.05)。乳中三聚氰胺含量随添加量的增加而显著增加(P<0.05),在MEL1、MEL2和MEL3这3个组的含量分别为5.48、28.32和51.96mg/L,乳中三聚氰胺产量分别为66.00、420.05和745.20 mg/d。饲粮中三聚氰胺向乳中转化的效率在3个组间无显著差异(P>0.05),平均转化率为(0.51±0.10)%。在停喂三聚氰胺后牛奶中三聚氰胺含量迅速降低,在停喂后第3天三聚氰胺残留量均低于0.05 mg/L。综合本试验结果可知,泌乳奶牛日粮添加三聚氰胺可显著提高牛奶中三聚氰胺残留量,但对奶牛干物质采食量、产奶量和乳成分无显著影响。     

浅谈降低畜产品质量安全隐患的对策

随着人们生活水平的提高,肉、蛋、奶等畜产品已经成为人们餐桌上重要的组成部分.但近几年,全国范围内出现了一系列有关畜产品质量安全的违法案件,如:2003年以来,"瘦肉精"中毒事件时有发生;2006年发生"红心鸭蛋"、"多宝鱼"事件;2008年发生了"三鹿"婴幼儿奶粉事件等.畜产品质量安全问题,逐步引起了公众及国际社会的广泛关注.我结合本职工作,就如何采取措施,降低畜产品质量安全隐患,谈一下自己的见解.     

褪黑激素在短光照影响KAP基因表达中的作用研究

为了研究短光照对和田羊血浆褪黑激素(MEL)浓度和皮肤KAP基因表达的影响以及MEL浓度与KAP基因之间的相关性,试验以健康的12只和田公羊为研究对象,采用ELISA和半定量RT-PCR等方法检测血浆MEL浓度及KAP3.1、KAP7和KAP8三种基因的mRNA表达量并对其进行相关性分析。结果表明:KAP3.1、KAP7和KAP8的mRNA表达量呈昼低夜高的变化趋势;血浆MEL浓度的变化与KAP3.1、KAP7和KAP8基因的mRNA表达量具有相似的变化趋势;MEL浓度与KAP3.1、KAP8 mRNA表达之间存在显著相关性(P0.05),MEL浓度与KAP7 mRNA表达之间不存在显著相关性(P0.05)。说明短光照可能通过MEL浓度而影响KAP3.1、KAP8基因的表达,从而影响和田羊绒毛的生长和品质。     

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。     

动物性食品中三聚氰胺研究进展

动物性食品中三聚氰胺的检出,引起了全世界广泛的关注,因此动物性食品中三聚氰胺的检测方法的研究成为了关注的热点问题.论文综述了三聚氰胺的代谢、毒性、检测以及国内外检测方法的研究进展.     

我国乳品安全监管体系及法规框架研究

我国乳品工业在近三十年来在获得迅速发展的同时也暴露出众多问题.在2008年发生“三聚氰胺事件”后,我国加快了对食品安全法规的制、修订,尤其是对于乳制品的各项管理措施逐步趋于完善.文章从监管体系和法规框架的角度对国内及进口乳制品的监管现状进行阐述,指出当前监管模式下奶源监管仍存在问题,国家和社会团体在此方面有待发挥更大的作用,为更好的促进乳业的健康发展提供相关建议.同时指出在当前复杂多变的食品安全局势下,监管工作面临着巨大的挑战,逐步构建以政府为主导、社会力量为补充的多元化监管体系,或将是我国食品安全体系改革的一条重要思路.     

关于苜蓿产业发展对粮食安全影响的政治经济学思考

“三聚氰胺”事件后,国内对于优质奶产品的需求骤升,苜蓿（Medicago spp.）作为“牧草之王”,苜蓿产业作为“牛奶生产的第一车间”,愈加受到人们的关注。同时,也又一次引发人们对国内牧草产业如何发展的思考。本研究基于国家粮食安全和综合效益的视角下,在探讨粮食安全和食物安全的实质内涵以及奶产业素质提升的必要条件的基础上,重点实证分析了苜蓿产业发展对粮食安全的影响,并就未来如何发展苜蓿产业提出了自己的看法和见解,以期为我国苜蓿产业和奶业的发展提供参考。     

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.     

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.     

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。     

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.     

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.     

三聚氰胺对小白鼠亚慢性毒性

将80只昆明小白鼠随机分为4组（每组20只）：空白对照组（Ⅰ组）、三聚氰胺高剂量组（300mg／kg）（Ⅱ组）、三聚氰胺中剂量组（150mg／kg）（Ⅲ组）和三聚氰胺低刺量组（37．5mg／kg）（Ⅳ组）,试验周期为30d。试验期内观察小白鼠一般情况、体质量变化及食物利用率。结果显示：三聚氰胺染毒组小鼠体增重缓慢,食物利用率极显著降低（P〈0．01）;Ⅱ、11组小鼠血清ALT、AST、BUN、Cr和UA值显著高于Ⅰ组（P〈O．05）,Ca和P显著低于Ⅰ组（P〈0．05）;Ⅱ组小鼠肝、肾指数显著高于I组（P〈0．05）,Ⅱ、Ⅲ组脾指数显著低于Ⅰ组（P〈o．05）;Ⅱ、Ⅲ组小鼠肺、肝、脾、肾及膀胱有病理变化。结果表明,三聚氰胺亚慢性毒性会影响动物生长,造成肺、肝、肾及脾损害。