不同酸溶解体系下饲料用膨润土中铬的测定     

陆梅  李宏 《西北农业学报》2022,(4):407-412

旨在研究有效溶解饲料添加剂中三氧化二铬、硫酸铬等难溶物的方法,克服铬测定结果偏低的问题.试验选取饲料用膨润土试样,分别采用硝酸常温溶解体系、盐酸热溶解体系、盐酸—溴酸钾溶液热溶解体系3种方法进行样品前处理,利用火焰原子吸收分光光度计进行铬含量测定,分析比较3种处理体系对饲料用膨润土中铬测定结果的影响,择优选出盐酸—溴酸...  相似文献   

Determination of reaction rate parameters for the acid copper chromate fixation reactions on oak (Quercus castaneifolia C. A. Mey) sapwood     

Mohsen Sheikholeslami  Antonio Pizzi  Ahmad Mirshokraie 《Wood material science & engineering》2018,13(1):1-6

Acid copper chromate fixation reactions on oak (Quercus castaneifolia C. A. Mey) sapwood were characterized by at least two distinguished reaction periods which differ in their kinetic behavior, particularly reaction rate. In this research, chemical rate equation parameters were studied in detail as a function of chromium fixation time. Theoretically, the kinetic data were distinguished between the adsorption and reduction reactions and consequently, the rate parameters were determined for each stage distinctly. The obtained results showed that at the investigated thermal range (25–33°C), almost for every 3°C increase in temperature the reaction duration has decreased 20.4?min for the first reaction period and 78?min for the second reaction period. Besides that, in all sample replications, up to 58.3% of hydrogen ions function at the reduction reactions of the initial period, demonstrating that acidity (H⁺ ions) has a major effect on reaction rate constant. Accordingly, adsorption reactions of the hexavalent chromium at the starting point follow a pseudo-first-order kinetic reaction. Different to the adsorption reaction the Cr^VI reduction reaction is exothermic with a measured exothermal energy of 48.2?kJ/mol.  相似文献   

Direct embryotoxicity of chromium (III) exposure during preimplantation development     

Yuhe TIAN  Qisheng ZHU  Jiayu YUAN  Robert KNEEPKENS  Yuan YUE  Chao ZHANG 《The Journal of reproduction and development》2021,67(4):283

Chromium in its trivalent form (chromium (III)) is an essential component of a balanced diet, and its deficiency disturbs glucose and lipid metabolism in humans and animals. The prevailing view is that chromium (III) is notably less toxic than chromium (VI), which is genotoxic and carcinogenic. Thus, the biotransformation of environmental chromium (VI) to chromium (III) is a promising and environmentally friendly detoxification method. However, increasing evidence suggests that chromium (III) induces considerable cytotoxicity. However, the toxicity of chromium (III) to early embryos remains largely unknown. In the present study, we used in vitro fertilization (IVF) to produce mouse embryos and identified the direct embryotoxicity of chromium (III). On exposure to high concentrations of CrCl₃, blastocyst formation almost completely failed and a large proportion of embryos were arrested at the 2- to 4-cell stage. At low concentrations of CrCl₃, IVF embryos showed a significant decrease in blastocyst formation, reduced total cell numbers, aberrant lineage differentiation, increased oxidative stress, and apoptosis. We also found that chromium (III) exposure during the preimplantation stage, even at low concentrations, led to impaired post-implantation development. Thus, our study substantiates the direct embryotoxicity of chromium (III) during preimplantation development and prolonged impairment of development potential. The results further highlight the potential adverse effects of chromium (III) on public reproductive health with respect to increased environmental enrichment of and dietary supplementation with chromium (III) complexes.  相似文献   

吡啶甲酸铬对产蛋鸡的生物安全性评价     

王钢  孙效名  廖秀冬  张丽阳  吕林  兰云贤  罗绪刚 《动物营养学报》2017,29(1)

本试验旨在研究饲粮添加不同水平吡啶甲酸铬对北京红商品产蛋鸡产蛋性能、血液生理生化指标、器官发育和主要脏器组织病理学变化的影响,进而评价吡啶甲酸铬对产蛋鸡的生物安全性。试验采用单因子完全随机设计,选用360只23周龄北京红商品产蛋鸡,按产蛋率和体重一致的原则随机分为4个组,每个组6个重复,每个重复15只鸡。各组分别在玉米-豆粕型基础饲粮中添加0、0.6、4.0和6.0 mg/kg(以铬计)的吡啶甲酸铬。预试期21 d,正试期70 d。结果表明:1)饲粮铬添加水平对试验全期产蛋鸡产蛋性能和器官指数无显著影响(P0.05)。2)饲粮铬添加水平除显著提高试验第35天产蛋鸡血浆谷草转氨酶活性(P0.05)外,对其他血浆生化指标和血液常规生理指标均无显著影响(P0.05)。3)饲粮铬添加水平对产蛋鸡主要内脏器官的发育均无明显影响,同时均未观测到产蛋鸡的心脏、肝脏、肾脏、卵巢和输卵管组织出现明显的病理学变化。以上结果表明,产蛋鸡玉米-豆粕型饲粮中吡啶甲酸铬的推荐添加水平为0.6 mg/kg时,具有10倍的安全系数,即饲粮中以吡啶甲酸铬形式添加6.0 mg/kg铬对产蛋鸡是安全的。  相似文献   

吡啶羧酸铬对高密度应激下肉仔鸡血清脂类的影响     

刘显军  陈静  石娇  边连全 《中国家禽》2006,28(1):16-18

在144只试验肉仔鸡日粮中添加5种水平的吡啶羧酸铬,另设一组对照组,研究吡啶羧酸铬对高密度应激下肉仔鸡血清脂类的影响。结果表明:高密度应激显著提高了血清中总脂、游离脂肪酸和胆固醇含量(P<0.05),而吡啶羧酸铬能有效地提高肉仔鸡的抗应激能力。与对照组相比,添加0.5～1mg/kg吡啶羧酸铬明显缓解由于应激而造成的血清脂类显著变化,其血总脂、游离脂肪酸和胆固醇含量显著低于对照组(P<0.05)。  相似文献   

不同形式铬对SD大鼠生长性能、胴体组成和血清生化指标的影响     

辜良英  许梓荣  查龙应  王敏奇 《动物营养学报》2007,19(3):258-263

本文旨在研究纳米铬和吡啶羧酸铬对SD大鼠生长性能、胴体组成及血清生化指标的影响。试验以30只平均体重为(80±5)g的SD雄性大鼠为研究对象,随机分为3组,每组10只。对照组饲喂基础日粮,试验1、2组分别在基础日粮中以吡啶羧酸铬和纳米铬的形式添加300μg/kg铬,预试期7d,试验期36d。试验结果表明:(1)纳米铬处理使SD大鼠的日增重和饲料利用率分别提高了12.68%(P<0.05)和32.92%(P<0.05);吡啶铬处理有提高大鼠日增重和饲料利用率的趋势(P>0.05);(2)纳米铬处理使SD大鼠瘦肉重增加了15.11%(P<0.05),脂肪率降低了24.42%(P<0.05);吡啶铬处理使大鼠瘦肉重增加了18.76%(P<0.05);(3)纳米铬处理使SD大鼠血清中胰岛素、葡萄糖、尿素氮和甘油三酯水平较对照组分别降低了45.38%(P<0.05)、31.84%(P<0.05)、48.75%(P<0.05)和38.46%(P<0.05);吡啶铬处理则使大鼠血清尿素氮浓度较对照组降低了57.62%(P<0.05),高密度脂蛋白浓度升高了26.15%(P<0.05)。因此,纳米铬能够促进大鼠生长,改善胴体组成。  相似文献   

补铬对断奶仔猪代谢、免疫功能和生产性能的影响   总被引：2，自引：1，他引：2  

代建国  党姗  金刚  钟志平  陆伟  王燕 《畜牧与兽医》2007,39(3):16-19

选择(32±2)日龄、平均体重为(8.24±0.85)kg的三元杂交(杜×长×大)仔猪108头,随机分为3个处理,分别饲喂基础日粮、基础日粮添加甲基吡啶铬(C r3+含量200μg/kg)和基础日粮添加酵母铬(C r3+含量200μg/kg)3种日粮。试验持续4周,猪只自由采食和饮水。结果表明,日粮补铬对仔猪血浆铬、尿素氮、葡萄糖、甘油三酯、总蛋白、球蛋白、白蛋白等含量无显著影响(P>0.05);对卵清蛋白抗体效价、猪瘟(SFV)抗体效价以及经植物凝集素(PHA)刺激后皮褶厚度(DST)的变化无显著影响(P>0.05);对仔猪平均日增重(ADG)、平均日采食量(ADFI)和饲料转化效率(FCR)也均无显著影响(P>0.05)。结果提示,尚不能确定在生产实践中添加铬对仔猪免疫和生产性能的促进作用。  相似文献   

Phytoaccumulation of chromium by some multipurpose-tree seedlings     

Arun K.?ShankerEmail author  V.?Ravichandran  G.?Pathmanabhan 《Agroforestry Systems》2005,64(1):83-87

A pot culture experiment was conducted in green house to study the potential of chromium (Cr) phytoaccumulatory capabilities of four promising agroforestry tree species viz., Albizia amara, Casuarina equisetifolia, Tectona grandis, and Leucaena luecocephala. Possibility of enhancement of Cr uptake by chemical (citric acid) and biological vesicular arbuscular mycorrhizal fungi (VAM) amendments were also tried. Biologically stable speciation of Cr trivalent (Cr(III) and hexavalent Cr(VI) were used. Cr(VI) was more toxic to the tree growth in terms of collar diameter (CD) increment in all the tree species than Cr(III). In general, roots accumulated more Cr than shoots in all the tree species. There was more than 10 fold increase in root Cr content in comparison with shoot Cr content in all the trees at all the concentration of Cr and all sources of Cr. Citric acid significantly increased the Cr content in the tissues of roots in all the species under both speciation of Cr. The highest increase in Cr content brought by 20 mM citric acid addition was in A. amara. Unlike citric acid, VAM treatment did not bring about a significant increase in the Cr content of all the tree species studied. Results suggest that Albizia amara is a potential Cr accumulator with citric acid as soil amendment. The potential of this tree as a Cr phytoaccumulator may be investigated in long-term studies.  相似文献   

东北主要绿化树种对大气重金属污染物吸收能力的研究   总被引：3，自引：0，他引：3  

穆立蔷  孙海燕祝宁 《林业研究》2004,15(1):73-76

本文于2003年9月到10月在哈尔滨市主要街道采集和分析主要绿化树种的树叶，研究测定了东北主要的24种乔木树种和6种灌木树种对大气重金属污染物铅、镉、铬、汞的吸收能力。结果表明：绿化树种对铅、镉、铬、汞具有一定的吸收能力，并依污染物和树种的不同而有明显差异；根据不同树种对不同大气重金属污染物吸收量的差异将其各分为三级，其中吸铅量高的树种有白桦、垂枝榆和京桃等；吸镉量高的树种有小黑杨、钻天杨、银中杨和旱柳等；吸铬量高的树种有黄菠萝、紫丁香、旱柳、黑皮油松、红皮云杉、京桃、榆叶梅和糖槭等；吸汞量高的树种有榆叶梅、蒙古栎、旱柳、接骨木、野梨和华北绣线菊等。本研究为在不同大气重金属污染条件下选择不同绿化树种提供了科学依据。表4参11。  相似文献   

重金属铬对金鱼的毒性效应及鳃的组织学影响   总被引：1，自引：0，他引：1  

雷忻  杜团  廉振民  延志莲  白重炎 《水生态学杂志》2009,30(5):71-74

为了探讨重金属铬 (chromium, Cr) 对鱼类的毒性效应,为环境质量评价及环境监测提供可靠的科学依据。以金鱼 (Carassius auratus) 为受试动物,采用单因子急性毒性实验法及显微观察法,检测了Cr 对金鱼急性毒性作用以及鳃的组织学变化,并统计半数致死浓度 (Median lethal concentration, LC50 )和安全浓度 (SC)。结果表明：Cr 的24h, 48h, 72h, 96h的半致死浓度 (LC50) 分别为387.1 mg/L、370.9 mg/L、281.9 mg/L、200.2 mg/L,安全浓度 (Safe concentration, SC) 为102.176 mg/L。组织切片结果显示：Cr 使鳃小叶细胞脱落,鳃小叶变细。Cr 为中等偏高毒性的重金属污染物,对金鱼的毒性作用是随着体内积累的浓度增加而增强,并可造成鳃组织的严重受损。  相似文献