稀土元素在动物营养中的作用

本文就稀土在动物营养中的作用,包括稀土通过其代谢沉积作用减少动物体内多种毒素,并通过参与动物代谢和调节其代谢环境而影响中间代谢过程等进行了综述。     

稀土及其螯合物在鸡上的研究应用

稀土元素是元素周期表中镧系元素及化学性质相似的钪、钇等17种元素的总称。国内外研究证明,稀土是一种生理活性物质,与动物营养代谢密切相关。稀土螯合物结合了稀土和与之螯合物质的特性,更能发挥稀土和螯合物各自的作用。随着对稀土研究的深入,其在畜牧生产中的应用必将发挥积极的作用。     

新型高效生物激活剂—稀土添加剂

稀土饲料添加剂是一种稀土有机化合物,主要由镧、铈、镨、钕等17种稀有元素所组成。将稀土加入饲料中喂养动物具有3大作用,首先稀土元素与动物体内必需元素之间存在着密切关系,能促进必需元素的消化吸收。同时在一定范围内有替代必需元素的作用。二是稀土通过提高体内酶的活性,使酶与     

稀土饲料添加剂在畜牧业中的应用

我国稀土资源丰富 ,其储量、产量均居世界之首 ,稀土应用涉及工业、农业、医疗、纺织等领域。稀土农业应用在我国稀土应用各领域中已经位居第三位 ,成为发展最快的领域之一 ,我国已经率先在国际上建立了稀土农用产业。近年来稀土在畜牧业中的推广应用步伐不断加快 ,在北京、内蒙古、湖南、江苏等地都有大规模应用。下面对稀土在畜牧业中的应用进行论述。1　稀土的作用机理1.1　稀土是动、植物必需微量元素吗 ?江西省工业卫生研究所对兔子饲喂适量稀土 ,进行亚慢性毒性饲养试验时 ,发现兔子增重速度加快、被毛光泽度及皮下脂肪厚度也提高 ,首…     

有机稀土料精饲喂产蛋鸡效果

稀土作为饲料添加剂的历史不长,但一系列应用研究已表明稀土可以促进畜禽生长,提高饲料报酬。尽管到目前为止对于稀土促进动物生长的作用机制还很不明了,但内蒙、甘肃等地已作了较大规模的推广性实验,有的甚至重复作了几年并取得了确实的效果。有试验表明,稀土的应用效果在一定程度上依赖于基础日粮,特别是其预混料的水平。几年来,养殖业中无论应用性研究或实际生产中采用的稀土大多为无机稀土、氧化稀土或硝酸稀土。张国思等(1991)的研究表明,有     

稀土元素在动物营养上的应用

我国稀土资源丰富,其储量、开采量均居世界首位,已广泛应用于工业、农业等领域。稀土元素作为动物饲料添加剂,可以促进畜禽生长、减少死亡率、增强免疫等生理作用,在动物营养中应用的前景广阔。论述了稀土资源的分布、添加剂的种类、作用机理以及在动物营养中的应用做一综述。     

稀土的生物化学效应及其在养殖业上的应用

稀土元素（haEalthElementS，简称RE）是斓系元素与抗、记何个元素的总称。稀土位于周期表中皿B族，因天然丰度低而得名。早在本世纪初，国外就有人研究了稀土的医药作用，30年代初苏联植物学家发现稀土对植物具有较强的生理活性。70年代后期，我国农学家和有关专家协同攻关，研究了稀土作为微肥施用对多种农作物的增产作用和使用技术。在稀土农用的启发下，研究人员对稀土的生物化学效应及其在养殖业的应用进行了大量的试验和研究，取得了令人瞩目的成绩。现已发现，稀土具有促进畜禽生长、提高生产水平和降低饲料消耗等作用。本文就稀…     

浅淡在饲料中添加稀土的效果

稀土是由稀土矿通过煅烧而成的，它包括化学元素周期表中镧系１４种元素，其中钪和钇在天然矿石中不单独存在。按原子序数可把稀土分成重稀土和轻稀土，目前常用的多为轻稀土，呈弱碱性，产品有硝酸稀土，氯化稀土、碳酸稀土和有机稀土。我国稀土资源十分丰富，是世界上储量最多的国家，为国外总储量的５倍多，主要分布在内蒙古、江西、湖南、广东和福建等省，矿物类型多、开采价值高，我省稀土矿位于与江西邻近的闽西，以钇、镧、钛为主，且为离子吸附型矿。１稀土元素对动物的作用：研究报道稀土是一种生理激活剂，可刺激动物体内的新陈代…     

鸡饲料中添加稀土化合物效果研究

<正> 稀土是镧系15种元素与钇、钪共17种金属元素的统称。由于这类元素具有特殊的活泼性而在冶金、电子、化工、光学、轻工等众多领域得到广泛应用。30年代以来,国外学者对稀土元素的生理活性曾做过一些研究。近20年,我国在稀土农用研究上有一系列突破,成功地将稀土应用于我国农业生产,为稀土的应用开辟了一个新领域。配合稀土农用进行的稀土毒理学研究,曾发现一些稀土元素对动物有一定的生理作用。80年代中后期陆续开始的稀土对畜、禽、鱼的作用研究都取得了可喜进展。本文报道的是稀土化合物应用于养鸡的研究结果。5年来通过小试、中试、示范试用等试验程序,肯定了稀土对肉仔鸡和产蛋鸡生产性能的影响,并确定了在饲料中的适宜添加剂量、饲喂方法及经济效益。     

添加稀土日粮饲养肉用仔鸡的效果

稀土是元素周期表中镧系及性质相近的钪、钇等17种金属元素的总称。其中铈48%、镧25%、钕16%、钐2%、镨5%,其他12种元素仅占4%。近年来,国内外研究工作者已经发现,稀土对提高动、植物产量有较好的作用。为了探讨稀土在肉用仔鸡中应用的可行性和增产效果,我们进行了本试验。     

微肥、稀土对苜蓿产量和品质的影响

在土壤瘠薄、盐碱较重的地段研究微肥、稀土对苜蓿产量及品质的影响,结果表明:喷施微肥及稀土对苜蓿有明显增产作用,200 g/kg稀土液产量最高,为16 708.40 kg/hm2,比对照高24.74%;施肥后粗蛋白含量明显提高,100 g/kg稀土液效果最好,两茬分别为22.14%、23.30%,比对照提高35.99%、30.75%;喷施微肥及稀土可增加苜蓿种植的经济效益,200 g/kg稀土液,净增收1 979.52元/hm2。     

稀土元素的肝脏蓄积性及毒性危害

综合论述了稀土元素在机体肝脏的蓄积性及其毒性效应,分析了稀土农业应用对生态环境和人群健康的危害.稀土元素被长期低剂量摄入,可在肝脏中蓄积,导致肝脏形态和病理组织变化、肝细胞损伤、肝代谢紊乱引起脂肪肝;高于2 mg·kg-1剂量的农用稀土(常乐)仍能通过胎盘屏障引起肝细胞和发育中的红细胞DNA损伤.     

Validity of specifically applied rare earth elements and compartmental models for estimating flux of undigested plant tissue residues through the gastrointestinal tract of ruminants

The validity of using rare earth elements as flow markers of undigested residues was evaluated by comparing mean gastrointestinal residence time (GMRT) of rare earths specifically applied to cottonseed hulls (CSH) to that of the indigestible fiber of CSH. Feces were collected from five lambs fed a mineral supplemented diet of CSH containing 52 g CP/kg DM and five lambs fed a CSH plus cottonseed meal diet (CSH+CSM) containing 123 g CP/kg DM. Rare earth elements (La, Yb, and Tb) specifically bound to CSH were included in the diet for a 5-d period and then deleted from the diet for a 3-d period. Following the last fecal collection, lambs were slaughtered for collection of digesta from segments of the gastrointestinal tract. Potentially indigestible NDF (PIF) was determined in diets and digesta from each segment of the gastrointestinal tract. Mean turnover rate, time delay, and GMRT for each rare earth element was estimated by fitting an age-dependent compartment model to profiles of markers appearing in the feces (compartmental model-marker method, CMM). The GMRT also was computed by the indigestible entity pool dilution method (IEPD) as grams of PIF in sampled segment/mean intake rate of PIF proceeding slaughter, g/h. The GMRT computed by the CMM and the IEPD methods did not significantly (P < 0.05) differ (99.6 vs 94.8 h and 58.9 vs 59.5 h for CMM vs IEPD and CSH and CSH+CSM diets, respectively). Regression of GMRT estimated for rare earths vs PIF yielded a highly significant regression (P = 0.001) with a regression coefficient of 0.94 +/- 0.016. It was concluded that rare earth elements applied to specific feeds are valid flow markers for the undigested residues derived from such marked feeds.     

稀土元素对动物及人的影响

稀土农用给中国农业带来巨大经济效益,已涵盖了农业、林业、渔业、牧业以及家畜(禽) 养殖业,对农业生态环境也造成潜在的负面影响,而稀土元素是否是动物的必需元素尚无定论。在稀土农用中应充分考虑其对环境与人体的影响。作者就目前稀土元素研究现状,稀土元素在饲料添加剂中的应用及获得的效果,以及对人体健康的影响进行了综述。     

RARE EARTH INTENSIFYING SCREENS FOR VETERINARY RADIOGRAPHY: AN EVALUATION OF TWO SYSTEMS

Two rare earth radiographic intensifying screen-film systems were compared with a calcium tungstate screen-film systems in a series of clinically oriented trials. The calcium tungstate screen-film system was subjectively judged to have the highest overall image quality, primarily because of its wide latitude. Several rare earth screen-film combinations produced radiographs of excellent diagnostic quality. In general, image quality was inversely related to screen-film speed, whereas radiation protection was directly related to screen-film speed. Medium-speed rare earth screen-film combinations resulted in reductios of scatter radiation on the order of 30 to 70 percent compared with the par-speed film combination. Recommendations are made regarding the use of specific rare earth intensifying screen-film combinations in small and large animal diagnostic radiography.     

Rare earth elements--a new generation of growth promoters for pigs?

The present study which includes two feeding experiments was performed to investigate a possible performance enhancing effect of rare earth elements (REF) in piglets. This performance enhancing effect has been described in the Chinese literature for a long time, however, it was never tested under "western conditions". In the first feeding experiment 72 piglets at a mean BW of 7.3 kg were allotted to a control and to 4 REE groups at different levels of lanthanum chloride or an REE mixture containing mainly chlorides of lanthanum, cerium and praseodymium. The experimental period lasted 5 weeks. Positive effects of REE were found on body weight gain as well as on feed conversion ratio of the piglets. Compared to the control group, the daily weight gain was improved by 2 to 5% and feed conversion was better by up to 7%. These effects were, however, not significant. In the second feeding experiment, piglets (mean BW 17.3 kg) were fed for 8 weeks with a similar REE mixture. Significant positive effects of REE were found on both body weight gain and on feed conversion ratio by 19% and 10%, respectively. This is the first time that a performance enhancing effect of REE in pigs under western feeding conditions has been shown. Since the use of antibiotics as growth promoters in animal feed has been restricted in the European Union recently, rare earth elements might be of interest as new, safe and inexpensive alternative performance enhancers.     

添加稀土对蛋鸡生产性能影响的研究

蛋鸡饲粮中添加300mg/kg、400mg/kg的有机稀土络合物，观察其对蛋鸡产蛋率、平均蛋重、采食量等的影响。结果表明：添加稀土能显著提高产蛋率，两试验组分别比对照组高出3.54和6.18个百分点；而对蛋重、采食量影响不大。     

蛋氨酸锌在反刍动物生产中的应用

锌是动物体内必需的微量元素,是生物学功能研究得最为深入的微量元素之一。蛋氨酸锌是20世纪70年代由美国首先研制成功的新型饲料添加剂。它是锌与蛋氨酸螯合态化合物,既是一种过瘤胃蛋白,也是接近于动物体内天然形态的微量元素补充剂。与无机锌饲料添加剂相比,不仅具有良好的化学稳定性和生化稳定性,而且能提高微量元素的生物利用率,显现出易消化吸收、抗干扰、毒性小、改善动物生产和繁殖性能、增强免疫功能等特点,是理想的反刍动物高效微量元素饲料添加剂。在生产中具有广阔的应用前景。     

微量元素在反刍动物生产中的应用

微量元素在反刍动物体内发挥着重要作用,作者阐述了微量元素在反刍动物体内的营养作用,以及其对反刍动物生产性能、繁殖性能和瘤胃微生物的影响。为合理补饲微量元素、调控瘤胃发酵、提高生产性能和繁殖性能提供参考依据。