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目前生产所用的秋用蚕种 ,多为当年制种经冷藏、浸酸等技术处理后的冷藏浸酸种 ,其孵化率的高低 ,除蚕种本身的内在质量外 ,还与蚕种的冷藏保护、浸酸技术处理的效果密切相关。为探讨秋用蚕种的入库冷藏时期、浸酸与孵化成绩的关系。笔者于 2 0 0 2年对蚕种的冷藏保护、浸酸处理进行了试验和调查。现将试验及结果介绍如下。1 试验方法1 1 供试蚕品种菁松×皓月 (正反交 )、夏芳×秋白 (正反交 )。1 2 试验方法1 2 1 制种当日的蚕种 ,每个样抽取 0 .5张 ,按同品系、同品种、卵面基本一致的重复取样 ,共抽样 4 8个 (其中 :菁松×皓月 30… 相似文献
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室温浸酸早在1947年日本小针喜三郎首先在即时浸酸时采用。由于不需要加温装置,操作简便孵化良好,10余年来我所不论是春制蚕种还是早秋制蚕种;即时浸酸或冷藏浸酸;各种试验种或农村小批量用种都采用室温浸酸。现将多年来实践所得总结如下,以供参考。 相似文献
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<正>即时浸酸蚕种主要是用于夏蚕和早秋,近些年由于农村蚕桑生产的布局调整和有些品种上的需要,复式种不能满足生产需求,我们每年都做了一部分的即浸蚕种,5年我们共即浸蚕种63批次,10.44万余张蚕种,良卵 相似文献
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即时浸酸蚕种的冷藏时间,一般以3～5天为宜,7天为限,但在实际生产中往往要超过7天,或者更长时间,才能满足用种时间上的需要。1988年,为了解决中秋用种时间上的矛盾,我们对调入的长兴县龙华蚕种场生产的早早秋蚕种,采取了即时浸酸后冷藏18天,然后出库催青发给农村饲养,经调查表明:蚕种孵化齐,一日孵化率高,蚕的生长发育正常,产茧量与冷藏浸酸种无明显差异。 相似文献
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<正> 我省历年来冷藏浸酸种需要冷藏50天才能浸酸,即使是秋用品种也需冷藏40天,否则孵化率不高。由于农村出库时间基本一致,有时一天出库数量能达10万张之多,面对如此巨大的出库量,冷库往往难于承受,即使能按时出库浸酸.但在蚕种配发上难以做到品种之间、批次之间的搭配完美。针对生产中这一实际问题,我们在“短期冷藏种接触高温冲击浸酸试验”基础上,于1991年着手研究短期冷藏种(没有达到生产规定的冷藏日数)出库浸酸、浸酸后再冷藏试验。1992年我们又做了重复试验,取得了较好效果。现将试验结果整理如下。材料与方法1.供试品种:1991年、1992年均是采用宿迁场春繁秋用的苏5×苏6及反交。 相似文献
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提高早秋冷藏浸酸种孵化率的几点思考 总被引：1，自引：0，他引：1
早秋用冷藏浸酸种由于冷藏时间短、解除滞育不够充分等因素影响,容易出现胚子发育不一,孵化不齐的现象。因此,如何提高早秋冷藏浸酸种的孵化率,一直是各场及蚕种冷库十分重视的一个问题。2002年早秋期,嘉兴蚕种冷库共浸酸了嘉兴、王店两个场春期生产的6个批次蚕种,其中有3个批次的蚕种孵化率不够理想,有个别批次实用孵化率甚至不到90%,影响了蚕种的正常供应。经分析认为,影响浸酸种孵化率的因素是多方面、综合性的,并对如何提高早秋冷藏浸酸种孵化率进行了认真的试验总结。下面就影响早秋冷藏浸酸种孵化率的主要因素及改进措施谈几点看法。1… 相似文献
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目前"两广二号"品种即时浸酸种利用率日趋增加,而即时浸酸种存在实用孵化率高低不一,造成收蚁量不足,影响蚕农增收的现状。为探索"两广二号"品种即时浸酸与蚕种孵化率高低的关系,便于生产上安全使用,笔者于2010年春、夏进行了即时浸酸蚕种浸酸适期和浸酸时间长短的试验,总结出有利于提高实用孵化率的浸酸适期为大多数卵色呈淡黄色,少数是黄色;浸酸时间为5～6分钟,达到收蚁齐一、收蚁量足的目的。 相似文献
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夏秋期蚕种常采用即时侵酸的方法来满足生产的需要。即时浸酸是指在产卵后一定的时间内给蚕卵以浸酸处理,停止其滞育进程,使胚胎活性化,进而发育至孵化的方法,在生产上广泛应用。为保证即时浸酸蚕种质量,达到孵化齐一的目的,笔者认为必须把好制种关,掌握四个浸酸关键。一、严格把好制种关是保证即浸蚕种质量的基础在制种过程中,产卵时间的控制,分批投绒制种,产卵后至浸酸前的保护等各个环节的技术处理都会影响即时浸酸种的质量。因此,要加强制种环节中的各项技术措施,把好制种关。1．调节好产卵期温湿度产卵室温度以25℃为中心… 相似文献
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苏5、苏6原种黑种冷藏浸酸试验 总被引：1，自引：0，他引：1
蚕种生产上常因布局变化或入库原种存在质量问题等,需要增加入库时却已过了冷藏浸酸的入库适期。为使一代杂交种生产不受影响,可采用黑种冷藏方法作为应急措施。关于杂交种黑种冷藏浸酸研究,李伟清等已有报道[1]。笔者等于1999年秋期进行了原种黑种冷藏浸酸试验,探讨符合生产要求的较短冷藏期原种黑种冷藏浸酸的实用方法。1 材料与方法11 供试蚕品种1999年春制苏5、苏6原种。12 试验方法取苏5、苏6原种各20蛾,每个品种分设2组冷藏处理,每组10蛾,产卵后都用25℃保护。第1组苏5、苏6各10蛾于产卵后第7天入库,第2组苏5、苏6各10蛾于产卵后第… 相似文献
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<正>延长即时浸酸种浸酸后冷藏的有效期限,以利调节蚕种的供应时期,提高蚕种的使用率已是蚕种生产的成功技术了。但是,笔者通过蚕种冷藏多年的生产实践,就如何延长即时浸酸种浸酸前的冷藏抑制和浸酸后的乙胚子、丙胚子、丁胚子不同发育阶段的冷藏抑制技术谈几点体会。1掌握浸酸适期即时浸酸时期适当与否,对蚕种孵化及死卵发生有密切的关系,浸酸过早,易发生死卵;过迟,蚕卵的滞育性趋向稳定,会引起孵化不齐甚 相似文献
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本文概述了猪的毛色类型、猪的毛色遗传模式,着重综述了猪毛色基因分子基础的研究进展,指出存在问题并就未来发展方向做了思考。 相似文献
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魏静 《四川畜牧兽医学院学报》2009,(4):28-32
在现代法律秩序中,商会自治规范是制定法的基础和必要的补充,甚至在某些方面替代了制定法;商会自治规范主要包括商会组织规范、行为规范、惩罚规范以及争端解决规范等;其效力仅及于其内部成员;商会自治规范和制定法之间存在冲突,但也存在整合的基础。 相似文献
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Effects of size of ingestively masticated fragments of plant tissues on kinetics of digestion of NDF
Ingestively masticated fragments were collected and sized via sieving. Different sizes of esophageal masticate and ruminal digesta fragments, and ground fragments of larger masticated pieces were incubated in vitro, and undigested NDF remaining at intervals of up to 168 h of incubation was determined. The ruminal age-dependent time delay (tau) for onset of digestion of NDF was positively correlated (P < 0.004) with the mean sieve aperture estimated to retain 50% of the fragments between successive sieve apertures (MRA). Degradation rate of potentially degradable NDF (PDF) and level of indigestible NDF were not related (P > 0.10) to MRA of masticated and ground fragments. Estimates of tau were positively related to MRA, with slopes of bermudagrass < corn silage < ruminal fragments of corn silage. It was concluded that fragment size-, and consequently, ruminal age-dependent onset of PDF degradation of a mixture of different fragment sizes results in an age-dependent rate of degradation of the more rapidly degrading of two subentities of PDF. Models are proposed that assume a tau before onset of simultaneous degradation of PDF from two pools characterized as having gamma-modeled age-dependency and age-constant rates. The ruminal age-dependent pool seems to be associated with the faster-degrading pool, and its rate parameter increases with range in MRA in the population of fragments. Conceptually, the ruminal age-dependent rate parameter for PDF degradation seems to represent a composite of several effects: 1) effects of the size-dependent tau; 2) range in MRA of the population of ingestively masticated fragments; and 3) subentities of PDF that degrade via more rapid age-dependent rates compared with subentities of PDF that degrade via age-constant rates. The estimated fractional rates of ruminative comminution of ingestively masticated fragments (0.060 to 0.075/h) were of a magnitude similar to the mean fractional rates of PDF digestion (0.030 to 0.085/h), which implies that ruminative comminution may be first-limiting to fractional rate of PDF digestion. The in vivo roles of ingestive and ruminative mastication of fragments on PDF degradation must be considered in any kinetic system for estimating PDF digestion in the rumen. These results and others in the literature suggest that the rate of surface area exposure rather than intrinsic chemical attributes of PDF may be first-limiting to degradation rate of PDF in vivo. 相似文献
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乳酸杆菌作为益生菌广泛用于人和动物.本文综述了乳酸杆菌改善宿主健康的机制.乳酸杆菌可通过产生抗菌物质如乳酸、过氧化氢、细菌素,或者通过竞争营养或肠道黏附位点来抑制致病菌;通过诱导黏附素的分泌或阻止细胞凋亡而增强肠道的屏障功能,从而保护肠道.文章重点讨论了乳酸杆菌表面成分(表面蛋白、脂磷壁酸和肽聚糖)与肠道受体(C型凝集素受体、Toll样受体和Nod样受体),阐述了他们结合后启动免疫调节信号,调控肠道免疫功能以发挥改善健康作用的机制. 相似文献
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以国际标准强毒Ｒ株人工感染非免疫产蛋鸡,定时扑杀,分别从鼻窦、眶下孔、气管、肺、气囊、卵巢和输卵管分离ＭＧ,并收集感染鸡所产蛋分离ＭＧ。结果表明,人工感染４８小时后上、下呼吸道及肺已被全面感染,９６小时气囊已被感染,１２０小时输卵管已能分离到ＭＧ,卵巢始终分离不到ＭＧ。人工感染鸡自１４４小时便能在其所产蛋中分离出ＭＧ。药物治疗能在７２小时内消除感染,油乳剂苗则需２４天后逐渐降低蛋内ＭＧ分离率,药物卵内注射、种蛋药浴、高温处理均能杀死卵内ＭＧ,但以研制的种蛋浸泡剂药浴效果为最好。 相似文献
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REASONS FOR PERFORMING STUDY: Centesis of the bicipital bursa using an 8.9 cm long spinal needle has been reported but the alternative of employing a 3.8 cm long hypodermic needle requires validation. OBJECTIVE: To compare the efficacy of 2 different methods of centesis of the bicipital bursa and to evaluate the usefulness of ultrasonographic imaging to determine the location of solution administered when centesis of the bursa is attempted. METHODS: For Trial 1, 6 clinicians, who had no previous experience of centesis of the bicipital bursa, attempted to inject a solution composed of an aqueous radiopaque contrast medium and physiological saline solution (PSS) into the bicipital bursae of 2/12 horses using the previously described distal approach to inject one bursa and a proximal approach to inject the contralateral bursa. The bicipital tendon and bursa were examined ultrasonographically before and after injection; and both shoulders were examined radiographically to identify the location of the medium. In Trial 2, another 6 clinicians, also with no previous experience of centesis, repeated Trial 1, using 6 horses, but the radiopaque contrast medium was mixed with air instead of PSS. RESULTS: Accuracy of centesis using the proximal approach was 39% and that of the distal approach 28%. Ultrasonographic examination of the shoulder allowed the location of solution and air to be accurately predicted in all 12 shoulders examined. CONCLUSIONS: Clinicians who have had no previous experience performing centesis of the bicipital bursa are unlikely to be successful in centesis using either approach. Radiographic examination after injecting a radiopaque contrast medium may be necessary to assess the success of centesis especially if bursal fluid is not obtained during centesis. Injecting air along with the radiopaque contrast medium provides more accurate ultrasonographic confirmation of centesis and better radiographic definition than does injection without air. 相似文献