原种催青积温调查及两种催青法的比较试验

目前春期蚕种催青通常有二种方法,一为传统的常规催青法,原种催青采用此法;二为二段定温简化催青法,一代杂交种催青多采用此法。70年代未曾有过两种催青法比较试验的报导,自此以后一代杂交种春期催青就逐步采用简化催青法了。我省的现行蚕品种多是80年代育成的新品种,其原种是否可     

做好一代杂交蚕种催青的几点体会

我站的催青室蚕种发放面广 ,涉及 9个乡镇 30 0个行政村 ,既有水乡平原 ,又有丘陵山区 ,东西部在饲养规模、水平、操作习惯及观念上相差极大。蚕种催青发放工作既要照顾到地方特点 ,又要考虑到补催青工作和收蚁方便 ,还要确保一日孵化率高 ,因此催青技术处理和管理上要求较高。1　严格掌握温湿度标准1 1　春期催青温湿度的掌握 　春期一般第 11d发种。戊3 前 2 2℃ ,干湿差 2℃～ 3℃ ;戊3 后 2 5℃ ,干湿差 1℃～ 2℃。但在出库后第一天、第二天的温度 ,可以根据发种日期与胚子情况作适当调节 ,一般掌握 19℃～ 2 0℃ ,用此温度保护 ,能使…     

原种催青需要关注的几个问题

<正>原种催青是按照蚕种生产计划预定的饲育日期,将蚕种放在人为控制的环境中,遵循蚕卵胚子各发育阶段的生理要求和化性变化规律,给予合理的环境条件,使其顺利发育,并在预定日期齐一孵化的保护技术。原种催青比之普通种催青,在控制孵化日期和催青条件上更为重要。正确进行催青期温、湿、气、光的调节和其他技术处理,对提高蚕种的孵化率和孵化整齐度,具有较大作用。1调好起点胚子催青前,进行起点胚子的调整,是取得孵化齐一     

适时催青 合理饲养

1.确定催青适期春期催青适期我场历年来以桑树发育程度为主要依据,对现行多丝量品种,我们认为只要能采到收蚁叶,就可着手催青,几年来我场桑树发育调查情况如下:     

简化蚕种催青温度试验

蚕种场进行蚕种催青的目的,不仅是使蚕种能在预定日期收蚁、实用孵化率高,蚁体健康,而且要求蚕蛾产越年卵。一般种场春期采用高温感光法催青,即从丙_2起点胚子用68°F保护,以后根据胚子发育逐渐用70°F、72°F、75°F加温,至戊_3胚子起到孵化用77—79°F高温和每日18小时感光。而秋期催青,由于外温较高,蚕卵前期(丙_2—戊_2,下同)放在冷库低温室75°F保护,后期(戊_3—已_5,下同)则在自然高温保护,感光同春     

改善催青设施提高蚕种催青质量

<正>蚕种催青质量是蚕茧丰收的基础,性能良好的催青设施是提高蚕种催青一日孵化率的重要保证。德清县乾元催青室催青设施建造于20世纪80年代,近年来经常发生故障,已进入维修高峰期。2010年春期在农业局及经作站领导的支持下,对催青室进行了WS-CQ型温湿度智能仪表自动控制系统改造,改进了催青设施,为确保蚕种催青质量提供了有力保障。     

越年蚕种延期冷藏试验初报

本试验将原计划春制越年春用或秋制越年春用的一代杂交种,延期冷藏到夏季(第2期冷藏90d)出库催青、饲养,其实用孵化率、催青死卵率及1-2龄饲养成绩等主要指标与对照种比较没有显著差异。     

搞好蚕种催青 提高一日孵化率

蚕种催青是养蚕工作的前奏 ,是重要的起点 ,其质量不仅决定着蚕种的胚子发育整齐度 ,孵化整齐度 ,而且还关系到蚁体强健和蚕茧产质量。对如何搞好蚕种催青 ,笔者有以下几点体会。1　合理确定出库日期1 1　出库时间根据我市一年四期的养蚕布局 ,春期出库时间往往依据桑芽发育情况 ,同时参照本地往年出库的经验及气象特征。我市桑品种以育 71 -1和湖桑 3 2号为主 ,一般从育 71-1开放 6～ 7叶 ,湖桑 3 2号开放 4～ 5叶为出库适期。本地自 1 998年以来 ,出库具体时间为春期 4月 2 2日至 2 4日之间 ;夏蚕数量很少 ,一般为 6月 2 2日左右出库 ;中…     

蚕种催青阶段卵量减耗调查

<正> 蚕种自出库催青或浸酸处理后,保护在一定的温湿度环境中,其蚕卵胚子即继续发育。在蚕卵胚子发育过程中,由于卵内营养物和水份的逐渐消耗,卵量也随之减轻。为了了解蚕种催青阶段卵量减耗情况,我们于1987年秋期和1988年春期作了初步调查,现将调查情况简述如下:调查蚕种分为春用种、秋用冷浸种和即浸种,每种别各取一对交品种,每品种各取两个样本。调查卵量以各品种张种卵量为单位。首次秤量时间:春用种为出库当日上午;浸酸种为浸酸次日上午。终至秤量时间(?)转青80～90%(即催青室发种时)。春用种采用简化催青标准催青。秋用冷浸种采用78～80℉保护。逐日进行秤量,视其卵量减耗情况。根据初步调查结果表明:蚕种自出库催青或浸酸处理后,直至蚕卵转青80～90%止,春用种卵量减耗3.49%,张种卵量减少     

春用杂交种催青的体会

做好春用杂交种的催青工作,提高蚕种孵化率,增强蚁蚕体质,是养好春蚕的第一个环节,在催青实践中,深切体会到,根据蚕卵胚子的发育要求,催青的温度、湿度、空气、光线等环境条件调节合理与否与蚕种孵化率的高低有密切的关系。而催青温度对胚子的发育速度和蚁蚕体质的影响最显著。因此,正确地掌握温度的调节,对确定发种和收蚁日期,减少收蚁批次是很重要的。现在着重谈催青温度方面的几个问题。一、胚子在不同发育阶段所需积温的调查目前春用蚕品种有苏_5×苏_6、华合×东肥671及其反交。在起点胚子齐一,蚕种素质良好的基础上,我们调查了几个关键性胚     

松嫩平原假苇拂子茅无性系种群的年龄结构

假苇拂子茅是典型的无性系禾草,分蘖节存活时间最多为４年,根茎存活的时间最多为３年;１龄级分蘖株生产力最高,１龄级 物质贮存能力最大,放牧场和割草场假苇拂子茅无性系种群的分蘖株均为增长型的年龄级蘖的物质生产;放牧扰动对假苇拂子茅无性系种群各龄级要茎的养分贮藏均有不利影响。割草场和放牧场假苇拂子茅潜在无性系种群均属于增长型的年龄结构。     

Distribution of radioactive cesium in edible parts of cattle

After the disastrous incident of the Fukushima Daiichi Nuclear Power Station, various agricultural, livestock and fishery products have been inspected for radioactive contamination with cesium in Japan. In this study, radioactive cesium was measured in various edible parts of cattle to verify the current inspection method for cattle, in which the neck tissues are generally used as samples. Radioactive cesium concentration in the short plate, diaphragm, liver, lung, omasum, abomasum and small intestine were lower and sirloin, tenderloin, top round meat and tongue were higher than that in the neck. There was no significant difference between the other organs (heart, kidney, lumen and reticulum) and the neck. Ninety‐five percent upper tolerance limits of the relative concentration to the neck were 1.88 for sirloin, 1.74 for tenderloin, 1.87 for top round and 1.45 for tongue. These results suggest that a safety factor of 2 is recommended for the radioactivity inspection of cattle to prevent a marketing of meat with higher cesium than the legal limit. Re‐inspection should be conducted using another part of muscle, for example, top round, when suspicious levels of 50–100 Bq/kg are detected in the neck.     

Selection and interpretation of clinical pathology indicators of hepatic injury in preclinical studies

This position paper delineates the expert recommendations of the Regulatory Affairs Committee of the American Society for Veterinary Clinical Pathology for the use of preclinical, clinical pathology endpoints in assessment of the potential for drug-induced hepatic injury in animals and humans. Development of these guidelines has been based on current recommendations in the relevant preclinical and human clinical trial literature; they are intended to provide a method for consistent and rigorous interpretation of liver-specific data for the identification of hepatic injury in preclinical studies and potential liability for hepatic injury in human patients.     

鸡胚胎性病原茵多重PCR检测方法的建立

为建立同时检测禽波氏杆菌(Bordetella avium)、沙门氏茵(Salmonella)、大肠杆菌(Escherichia coli)和绿脓杆菌(Pseudomonas aeruginosa)4种导致鸡胚死亡病原菌的多重PCR方法,本研究根据B.aviun的ompA基因、Salmonella的invA基因、E.coli的phoA基因和P.aeruginosa的toxR基因序列,各设计一对特异性引物进行多重PCR反应,并对反应体系和条件进行优化.结果显示,4对引物分别扩增出597bp、724bp、372bp和278bp的目的条带;并且特异性强不与其他非目的茵发生反应.经优化B.aviun、P.aeruginosa和E.coli多重PCR检测灵敏度达到104cfu/mL,而Salmonella为103cfu/mL.本研究建立的多重PCR方法为相关病原茵的快速检测提供方法.     

Genotyping of groups of cows to improve genomic breeding values of new traits

Genotyping females and including them into the reference set for genomic predictions in dairy cattle is considered to provide gains in reliabilities of estimated breeding values for selection candidates. This should especially be true for low heritability traits. By the use of simulation, we extended a genomic reference set for an existing trait by including a fixed number of genotyped first‐crop daughters for one or two generations of reference sires. Moreover, we calculated results for the effects of a similar strategy in a situation where for a new trait the recording of phenotypes has recently started. For this case, we compared the effect of two different genotyping strategies: first, to phenotype cows but to genotype their sires only, and second, to collect phenotypes and genotypes on the same cows. We studied the effects on validation reliabilities and unbiasedness of predicted values for selection candidates. We found that by extending the reference set with genotyped daughters it is possible to increase the validation reliability of genomic breeding values. In the case of a new trait, it is always better to collect and use genotypes and phenotypes on the same animals instead of using only sire genotypes. We found that the benefits that can be achieved are sensitive to the sampling strategy used when selecting females for genotyping.     

马克思主义与中国新文学史的建构——以《〈中国新文学史〉教学大纲》为例

建国后，《〈中国新文学史〉教学大纲》第一次将中国新文学史作为一门学科确定下来，也是第一次将马克思主义与中国新文学史学科相结合，为20世纪50年代的文学史书写提供了一个范例。《大纲》在马克思主义指导下服从于新的意识形态，是毛泽东的政治、文艺思想在新文学研究领域的演绎。新文学史的“革命知识论”与阶级斗争话语模式也在《大纲》的指导下初步形成。     

Parasites of the stomach in donkeys of the highveld of Zimbabwe

Fourteen donkeys from a communal area of the Zimbabwean highveld were examined for stomach parasites during July and November of 1986 and January and April of 1987. All 14 animals were infected. Habronema muscae occurred in 12, Draschia megastoma in 11, H. majus in 9, Trichostrongylus axei in 9, Gasterophilus intestinalis in 14 and G. nasalis in 1 donkey. The lowest level of infection was in January for the helminths and in April for Gasterophilus larvae. The peak burdens of parasites were in July for Habronema spp. and in November for D. megastoma and Gasterophilus larvae. Infections with spirurid worms and Gasterophilus develop mainly from the middle of the rainy season to the beginning of the dry season (January to May/June). G. intestinalis seems to have an annual cycle.     

High-speed centrifugation of extender of freeze-thaw boar semen

In semen cryopreservation, egg yolk is still widely used as a non-penetrating cryoprotectant. Much has been developed in the search for alternatives for this biological product. This work aimed to evaluate the processed egg yolk through ultracentrifugation and/or sonication in the cryopreservation of swine semen. Twenty-seven semen doses were purchased from a commercial boar stud and processed for cryopreservation using egg yolk lactose 11% (control) extender, processed using two different methods: high-speed centrifugation and sonication. Then, they were submitted to freeze-thawing protocol and were assessed for kinematic and cell structural parameters. Samples in which extenders underwent centrifugation had better results in velocity parameters, meanwhile those that only sonication was performed had poorest results in this parameter. The preservation of the membrane and mitochondria structure had better results when the diluent was only centrifuged in comparison with the other treatments. Therefore, centrifugation of extender containing egg yolk is important for better cryopreservation of swine semen.     

新疆西昆仑山禾本科植物物种多样性特点

通过实地考察和植物标本的采集与鉴定,并结合相关文献资料的查阅,对新疆西昆仑山禾本科植物物种多样性特点进行了研究。结果表明,新疆西昆仑山的禾本科植物共计37属137种,分别占新疆禾本科植物属、种总数的52.11%和42.55%,属种丰富度比较高;其中发现该区新记录植物6种。本区禾本科植物特有现象不明显,属的组成以仅含1种的属(17属17种)和少种属(13属35种)为主,共计30属52种,分别占属、种总数的81.08%和37.96%;中型属(4属32种)和较大属(3属53种)共计7属85种,分别占属、种总数的18.92%和62.04%,在种级水平占据明显优势,是该区系的主体。区系地理成分有6个分布类型和4个变型,以温带分布及其变型为主。植物生活型以多年生草本(116种,占84.67%)为主,其次为一年生草本(21种,占15.33%)。生态型以中生植物(63种,占45.99%)和旱生植物(61种,占44.53%)为主,显示其与草原、草甸的密切关系,另有少量湿生植物(13种,占9.49%)。说明该地区比较适合禾本科多年生的旱生和中生植物生长,且该区系的禾本科植物地理成分类型与该区所处地理位置为温带较吻合。