山东小尾寒羊研究概况

介绍了山东小尾寒羊的研究概况 ,主要内容包括该品种的繁殖性能、屠宰性能、杂交利用等方面的最新研究成果 ,比较全面地阐述了山东小尾寒羊的种质特性。     

Dietary Supplementation with Microencapsulated Lutein Improves Yolk Color and Lutein Content in Fresh and Cooked Eggs of Laying Hens

This study was conducted to compare the efficacy of diet supplemented with non-microencapsulated lutein (NL) and microencapsulated lutein (ML) in laying hens. A total of 270 Hy-line Brown laying hens (54 weeks old) were allocated to three groups with six replicates of 15 hens and were adapted to a wheat-soybean meal basal diet for two weeks. Next, the control birds were fed the basal diet, and the test birds were fed the basal diet supplemented with 600 mg/kg NL (12 mg/kg available lutein) or 90.1 mg/kg ML (10 mg/kg available lutein) for 35 days. Supplementation of lutein did not affect the productive performance of laying hens, but improved (P<0.05) the yolk color and red/green value (a*), with eggs from the ML group displaying improved color and a* values from the 15^th day of the experimental period. The blue/yellow value (b*) for the yolk showed an increase (P<0.05) through both NL and ML supplements. The yolk color of fried and boiled eggs and a* value of the yolk in fried eggs were improved (P<0.05) only through ML supplemented diet. Both NL and ML supplements resulted in lower (P<0.05) lightness and higher (P<0.05) a* values of yolk in boiled eggs, as well as higher (P<0.05) b* values in fried and boiled eggs. Yolk lutein content in fresh, fried, and boiled eggs was increased (P<0.05) in NL and ML groups with the latter being higher. In conclusion, ML improved yolk pigmentation and lutein retention in laying hens better than NL.     

抗生素对桑树外植体生长与分化的影响

试验比较了不同种类抗生素在不同浓度下对桑子叶、不定芽和新梢生长与分化的影响，结果显示：（１）培养基中卡那霉素浓度高于２０ｍｇ／Ｌ时．桑子叶不能形成不定芽；羧苄青霉素或头孢霉累大于４００ｍｇ／Ｌ时，子叶不定芽诱导率明显下降。（２）卡那霉素大于３０ｍｇ／Ｌ，羧苄青霉素或头孢霉累大于４００ｍｇ／Ｌ，不定芽抽茎受到明显抑制。（３）卡那霉素大于１０ｍｇ／Ｌ，羧苄青霉素或头孢霉素大于１００ｍｇ／Ｌ，桑树新梢难以形成根系。     

卡死克对草地天敌昆虫通缘步甲的影响

试验研究了卡死克对通缘步甲成虫的急性致死毒性及田间撒施卡死克毒饵后对其种群数量消长的影响。室内口腔灌喂250ppm浓度的卡死克药液2μl／头后的第1～15天，灌药组与灌清水组的存活率均在70～90％，统计结果无显著差异，说明药剂对该步甲元急性致死毒性。在毒饵撒施后的7～17天，采用陷阱诱捕法调查对通缘步甲田间种群数量的影响，结果表明：处理区与对照区的日均诱捕数量为28．3和28．5头，两区间的差异并不显著。卡死克既不杀伤草地上游猎捕食的通缘步甲又能有效控制蝗虫种群数量的增长，使其能够发挥控制害虫的作用。通缘步甲发生数量大，与蝗虫种群消长有跟随现象，是一种值得研究保护利用的优势天敌种类。     

嘉兴平原桑园土壤分类及肥力的调查

选择浙北嘉兴平原桑园代表性土壤，进行调查，研究其成因、分类及特性，并对高低产桑园土壤的理化性状进行化验分析，明确了嘉兴平原桑园土壤是历史上由人工堆迭而成，在分类系统上归属于潮湿土纲、正常潮湿土亚纲、潮土土类、暗潮土亚类、堆迭土土属，又分为粘质堆迭土、壤质堆迭土、粉质堆迭土３个土种。在统计众多土壤理化性状数据的基础上，暂拟本区高产桑园土壤１６项理化性状，作为本地区桑园地力建设的参考。     

Illustration of the maternal animal model used for genetic evaluation of beef cattle

National cattle evaluation programs for weaning weight in most beef breed associations involve implementation of the maternal animal model to predict direct and maternal EPD. With this model, direct breeding values are predicted for all animals with records or pedigree ties to animals with records, or both. Even though maternal genetic value is expressed only in animals that become dams, these effects are transmitted by all parents and inherited from parents by all animals, leading to maternal breeding values being predicted for all animals as well. A small example data set was simulated involving 12 parents, 8 nonparents, and 13 animals with weaning weight records. The pedigree was developed to include paternal and maternal half-sib families, full-sibs, and some inbreeding, similar to field populations of beef cattle. Assembly of the mixed model equations and solutions for the maternal animal model are illustrated explicitly to assist animal breeding students in their understanding of the properties of the maternal animal model and to explicitly implement the model. Model parameters and moments, fixed contemporary group solutions, adjustment of breeding values for merit of mates, interpretation of maternal permanent environmental effect solutions, and alternatives for the assembly of the equations are shown. This example should lead to increased student and producer understanding of genetic improvement programs for weaning weight in beef cattle.     

Eimeria tenella搭载科学卫星对虫体生物学特性影响的初探

为探讨微重力与太空辐射等因素对鸡球虫生物学特性的影响，我们首次将一株已孢化的柔嫩艾美耳球虫搭载于返回式科学试验卫星。卫星运行７天后返回地面。     

克伦特罗缓释药囊的制备,体外释药及对育肥猪生产性能的影响

选用可生物降的白氨酸，谷氨酸甲酯，谷氨酸三元聚物制成克伦特罗缓释药囊。体外释药研究所表明，药囊能保持长期缓慢恒速释药，释药速率随取合物中谷氨酸含量增多而增大，其中ＰＬＭＧＧ－２５的克伦特罗药囊释药时间为８０ｄ、稳态后每天释药量平均为１．２３ｍｇ／ｄ。     

An Example of Yak Paternity Assignment by Microsatellite Genotyping

12 cattle microsatellite DNA markers were used for establishing the paternity of 4 Datong Yak calves.The results indicated that paternity can be assigned by use of exclusion method directely when the mother is clearly known and data of all likely sires were obtained. The more the alleles of a locus possessed, the more effectively the paternity can be assigned. Not only the microsatellite DNA marker is a promising tool in establishment of yak detail pedigrees, but also can provide us information of reproductive efficiency of the bull(s) based on the numbers of calves it produced in the herd, which will be useful in speeding up the processes of yak genetics improvement.     

借鉴发达国家经验完善我国兽药残留控制法规体系

自20世纪80年代以来．食品安全性问题始终是世界范围内人们关注的焦点。兽药残留是影响动物源食品安全的主要因素之一。美国、欧盟等发达国家重视兽药及其他化学物的残留控制问题．制定了一系列有关兽药残留控制的法律法规．包括兽药的生产、销售和使用。确保动物源性食品的安全。我国这方面的法律法规尚不完善．很难保证动物源食品安全．影响了国内消费者的信心．损害了我国动物源食品在国际贸易中的信誉。