喹胺醇饲料添加剂对肉鸡生长的影响

将160只安卡红羽肉鸡随机分为4组,分别添加不同剂量的喹胺醇,测定试鸡血浆中总蛋白、白蛋白以及肌肉中RNA、DNA的含量;于28日龄时进行消化代谢试验。结果表明:喹胺醇有促进肉鸡生长,增强蛋白同化的作用,有利于氮的利用;在基础日粮中以添加50 mg/kg喹胺醇效果最佳。     

饲料添加剂喹胺醇在肉鸡组织中的消除及残留研究

[目的]为肉鸡饲料中添加喹胺醇提供科学依据,为食品卫生安全方面提供一个可靠的依据。[方法]采用乙腈-乙酸乙酯(3/2,V/V)提取组织中的药物,反相高效色谱法测定组织中喹胺醇的浓度,对鸡多次口服(50 mg/kg,每12 h 1次,连用6次)喹胺醇在肝脏、肾脏及肌肉3种组织中的残留进行研究。[结果]鸡多次口服喹胺醇,第6次给药后18 h肌肉、肾脏、肝脏中药物的浓度为(123.18±5.48)、(111.99±14.20)(、104.89±3.22)μg/g,24 h后3种组织中均未检测到喹胺醇;消除半衰期分别为6.05、6.926、.30 h。若规定组织中喹胺醇浓度最高残留限量为1μg/g可食用,则休药期为2.7 d。[结论]饲料中添加喹胺醇后休药2.7 d的肉鸡方可食用。     

Studies on the Mutagenicity and Teratogenicity of Kuianchun and Its Potential Carcinogenicity Prediction

Kuianchun is a newly synthesized antibacterial and growth-promoting drug. This paper selected a battery of three short-term tests, including Ames test, micronucleus test and sperm abnormality test, to detect the mutagenicity of Kuianchun. The carcinogenicity prediction and battery selection method (CPBS method) was used to determine the probability of carcinogenicity of Kuianchun based upon the results of shortterm tests mentioned above. In addition, traditional teratogenic test was selected to study teratogenicity of Kuianchun. In Ames test, Kuianchun showed mutagenic for Salmonella typhimurium strains TA98 and TA100 in the absence and presence of microsomal metabolic activation system (S9-mix). However, the mutagenicity was reduced by the addition of S9-mix. In micronucleus test, Kuianchun was administered intra-peritoneally to male mouse 30 hours and 6 hours before they were killed respectively. The result indicated that there was no significant difference on the number of micronucleated polychromatic erythrocytes (PCEs) in the mouse bone marrow induced by Kuianchun compared with the negative contrast (50% DMSO) (P ＞ 0.05). In sperm abnormality test, Kuianchun was administered through a gastric incubation to male mouse as a suspension in 2% Tween-80. The dosage levels were 450, 750, 1000 and 1500mg/kg per day for 5 days. The result indicated that the percentage of abnormal sperms induced by Kuianchun was not significant compared with the negative contrast (P＞0.05). In traditional teratogenic test, Kuianchun was given orally to pregnant mouse at 1/30,1/20 and 1/15 LDs0 during 6 - 15days of pregnancy period (the LD50 = 9000mg/kg). No toxicity was found either on mother and embryo in mouse, and teratogenic effects were also not observed at all tested dosages. The probability of carcinogenicity of Kuianchun is 23.8 % (θ = 0.238). The result demonstrated that Kuianchun is a non-carcinogen.     

Studies on Mutagenicity and Teratogenicity of Sarafloxacin

Wistar rats and closed Kunming strain mice were selected to study the genetic toxicity of sarafloxacin. The results indicated that sarafloxacin had no significant toxic effect of an excreted mutagen in S. typhimurium strains, and did not induce significantly higher percentages of polyehromatic erythrocytes with micronuclei (MNPCE) in mice. No significant mutagenic activity was observed in dominant lethal assay.At 5 and 50mg/kg b.w. , sarafloxacin did not produce significant effects on the reproductive parameters of litters and fetal growth, and did not induce the teratogenic effects on fetuses. Sarafloxacin induced some toxic effects on body length and skeletal growth in fetuses of 500mg/kg b.w., but had no significant dose - response relationship among the administered dosages of sarafloxacin. The results of the genetic toxicology above indicated that no evidence showing sarafloxacin was mutagenic and potentially teratogenic for animals.     

沙拉沙星的致突变性和致畸性研究

 选用Ｗｉｓｔａｒ大鼠和昆明系小鼠对沙拉沙星的遗传毒性进行研究。试验结果显示，沙拉沙星在抑菌剂量之下对鼠伤寒沙门氏菌不产生致突变作用；沙拉沙星不引起小鼠骨髓有微核多染红细胞率增加；显性致死试验中，沙拉沙星试验结果为阴性；５和 ５０ｍｇ／ｋｇ ｂ．ｗ．剂量沙拉沙星对母鼠的生殖机能和胎鼠的生长发育无明显影响，对胎鼠不产生致畸作用，而 ５００ｍｇ／ｋｇ ｂ．ｗ．剂量沙拉沙星对胎鼠体长和骨骼发育有一定影响，但不存在剂量反应关系。上述结果表明，沙拉沙星无明显的致突变性和致畸性。     

吡啶酸铬的致突变性和生殖毒性研究

 选用Wistar大鼠和昆明系小鼠对吡啶酸铬的遗传毒性进行研究。结果表明 ,吡啶酸铬在抑菌剂量下对鼠伤寒沙门氏菌TA97、TA98、TA10 0和TA10 2不产生致突变作用 ;吡啶酸铬经口染毒剂量为 5～ 0 .5g·kg-1BW时不引起小鼠骨髓有微核多染红细胞率增加 ;吡啶酸铬对小鼠的显性致死试验结果为阴性 ;饲料中添加 2和 2 0mg·kg-1剂量吡啶酸铬对母鼠的生殖机能和胎鼠的生长发育无明显影响 ,对胎鼠不产生致畸作用 ,而 2 0 0mg·kg-1剂量吡啶酸铬对胎鼠骨骼发育有一定影响 ,但不存在剂量 反应关系。由此得出 ,吡啶酸铬无明显的致突变性和致畸性。     

五指毛桃的致突变性研究

[目的]研究五指毛桃（Ficus simplicissima Lour.）水提物的致突变性。[方法]应用微核试验,对五指毛桃水提液致小鼠肝细胞、睾丸生精细胞、骨髓嗜多染红细胞和外周血淋巴细胞微核形成率进行检测。[结果]五指毛桃各剂量组对小鼠肝细胞、睾丸生精细胞、骨髓嗜多染红细胞和外周血淋巴细胞微核形成率的影响,与阴性对照组在0.05水平上无差异,但与阳性对照组在0.01水平有差异;各剂量组之间在0.05水平上无差异。[结论]在该试验条件下,五指毛桃水提物不具有致突变性。     

林蛙卵油多不饱和脂肪酸的急性毒性及致突变性研究

[目的]研究林蛙卵油多不饱和脂肪酸的安全性.[方法]通过经口急性毒性试验、骨髓微核试验和精子畸形试验,研究林蛙卵油多不饱和脂肪酸的急性毒性及致突变性.[结果]林蛙卵油多不饱和脂肪酸对小鼠一般状态没有影响,试验过程中未见小鼠死亡及其他毒性表现.林蛙卵油多不饱和脂肪酸的最大耐受剂量大于60 g/kg体重(小鼠,经口).根据急性毒性的分级标准,林蛙卵油PUFAs属于无毒级物质,安全性较高.[结论]该林蛙卵油多不饱和脂肪酸为无毒级物质、无急性毒性和致突变性,且安全性好.     

家木小蠹在中国潜在适生区的CLIMEX预测及风险分析

家木小蠹是中北欧阔叶树常见害虫,近年有入侵加拿大的报道,我国已数次从进口欧洲原木中截获该虫。利用CLIMEX对家木小蠹在中国的潜在分布区进行预测,结果发现：辽宁、河北、河南、北京、天津、山东、山西、陕西、云南、贵州、四川、重庆、江苏、安徽、江西、福建、广东、广西、海南等省份均是家木小蠹的适生区。运用多指标综合评估法对家木小蠹在中国的潜在风险进行评估,得出其R值为214,是高风险有害生物。     

诱导多能干细胞(iPSCs)及其医疗应用的研究进展

诱导多能干细胞(induced pluripotent stem cells)的研究是现阶段生命科学领域的热点之一,它建立了一种全新的、相对易操作而较稳定的体细胞核重编程方法,在生物学基础研究和临床应用方面具有潜在的价值。然而,研究过程中发现iPS细胞存在诱导频率过低、致瘤性、临床应用安全等一系列问题。目前,iPS细胞的研究主要集中于诱导方法的优化、iPS细胞转化率的提高以及iPS细胞癌变风险的降低等方面,并且在多个领域取得了重大突破。文中主要综述了iPS细胞的研究历程、iPS细胞的最新研究进展及其在医疗领域的应用前景。     

基于产量潜力预测的我国小麦单产分析

从小麦光合生产潜力、历年单产演变趋势、农作制区划潜力3个方面分析了我国小麦单产不同时期最高增产幅度：光能利用率潜力、历年产量演变趋势外推潜力、AEZ（农业生态区划）模型计算的我国小麦单产潜力,指出我国不同时期小麦单产的最高年增幅为：1991年以前10%;1996年以前9%;2000年以前8%。任何高于以上增幅的小麦品种或栽培技术都只能是局部推广的或有统计误差的。这对指导我国小麦生产具有参考意义。