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131.
Schlenker G Müller W Birkelbach C Glatzel P 《Berliner und Münchener tier?rztliche Wochenschrift》1999,112(1):14-17
Together with the faecal and the urinary discharge of animals and humans natural and synthetic estrogenes are excreted into the environment. About their degradation in the environment only few facts are known. Their reduction is probably of microbial enzymatical nature. For looking into that question it was investigated by in-vitro-attempts whether Escherichia coli or Clostridium perfringens influence the estrone. Therefore estrone was incubated together with the microorganisms tested (experimental groups) and without those (control groups) in nutrient medium for these bacteria over 48 hours with 37 degrees C (aerobic) or 42 degrees C (anaerobic). For the executed procedure an enzyme immunoassay was used. It could be seen that E. coli does not show a provable effect on the estrone concentration under this conditions. Whereas C. perfringens might have a potency for the degradation of the hormone tested. The experiments shows that there exists obviously a difference between estrone and 4-pregnene-20 beta-o1-3-one in the same system of test. 相似文献
132.
胡自治 《国外畜牧学(草原与牧草)》1999,(1):1-3
南美洲有草地面积844.5万km^2,饲养着草食家畜4.2亿头,其中牛为2.62亿头。热带稀树草原、亚热带温带潘帕斯草原、温带半荒漠、热带荒漠、热带干燥疏林与灌丛、热带雨林区的人工草地是主要草地类型。巴西和阿根廷是南美洲两个重要的草地资源大国,分别有草地面积1.69亿hm^2和1.42亿hm^2。 相似文献
133.
亚洲的草地资源及其评价 总被引:3,自引:0,他引:3
胡自治 《国外畜牧学(草原与牧草)》1999,(4):1-5,27
亚洲有草地面积20.78亿hm^2。中国、俄罗斯(亚洲部分)、哈萨克斯坦和蒙古国是亚洲的4个草地资源大国,它们的草地面积都在1亿hm^2以上。亚洲的天然草地类型繁多,从资源的角度看,主要是热带稀树草原,亚热带荒漠,温带荒漠,温带草原,温带草甸,高寒草甸和冻原等。 相似文献
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近年来,美国蛋的平均消费量持续下降。部分原因是由于人们厌食早餐,生活方式的改变。可是,在很大程度上是由于人们认为食品中的胆固醇会引起冠心病,从而影响了蛋的消费。因此,任何降低蛋中胆固醇含量的方法,都有助于养禽业。美国和其他国家的许多学者,对降低蛋中胆固醇含量进行了大量研究,试用了多种化学制剂,认为丙丁酚〔4,4’—(异丙叉二硫)—双(2,6—二特丁基酚)〕对降低蛋中胆固醇含量最有效。为研究丙丁酚对蛋鸡生产性能及蛋中胆固醇的影响,作者把72只40周龄星杂蛋鸡养在个体笼内(30.5×45.7cm)。试验设6种日粮处理,每种日粮设2个重复,每重复6只鸡。 相似文献
138.
Martín-Burriel I Rodellar C Cañón J Cortés O Dunner S Landi V Martínez-Martínez A Gama LT Ginja C Penedo MC Sanz A Zaragoza P Delgado JV 《Journal of animal science》2011,89(4):893-906
In Iberia there are 51 officially recognized cattle breeds of which 15 are found in Portugal and 38 in Spain. We present here a comprehensive analysis of the genetic diversity and structure of Iberian cattle. Forty of these breeds were genotyped with 19 highly polymorphic microsatellite markers. Asturiana de los Valles displayed the greatest allelic diversity and Mallorquina the least. Unbiased heterozygosity values ranged from 0.596 to 0.787. The network based on Reynolds distances was star-shaped with few pairs of interrelated breeds and a clear cluster of 4 breeds (Alistana/Arouquesa/Marinhoa/Mirandesa). The analysis of the genetic structure of Iberian cattle indicated that the most probable number of population clusters included in the study would be 36. Distance results were supported by the STRUCTURE software indicating a relatively recent origin or possible crossbreeding or both between pairs or small groups of breeds. Five clusters included 2 different breeds (Betizu/Pirenaica, Morucha/Avile?a, Parda de Monta?a/Bruna de los Pirineos, Barros?/Cachena, and Toro de Lidia/Brava de Lide), 3 breeds (Berrenda en Negro, Negra Andaluza, and Mertolenga) were divided in 2 independent clusters each, and 2 breeds were considered admixed (Asturiana de los Valles and Berrenda en Colorado). Individual assignation to breeds was not possible in the 2 admixed breeds and the pair Parda de Monta?a/Bruna de los Pirineos. The relationship between Iberian cattle reflects their geographical origin rather than their morphotypes. Exceptions to this geographic clustering are most probably a consequence of crossbreeding with foreign breeds. The relative genetic isolation within their geographical origin, the consequent genetic drift, the adaptation to specific environment and production systems, and the influence of African and European cattle have contributed to the current genetic status of Iberian cattle, which are grouped according to their geographical origin. The greater degree of admixture observed in some breeds should be taken into account before using molecular markers for genetic assignment of individuals to breeds. 相似文献
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