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孵化期间种蛋失重规律的研究 总被引：3，自引：0，他引：3
种蛋在孵化期间因营养物质的消化、水分的蒸发而失重。种蛋的失重率与出雏之间存在着复杂的关系。种蛋在孵化期间的失重率可因品种、孵化条件而改变。 Ｊｏｓｅｐｈ等（１９８８）认为种蛋的最佳失重率为１２％～１３％;杨长城等（１９８７认为番鸭种蛋在孵化期间的失重率为 １０％～１２％。耿照玉、王秀玲（１９９０）用海佩科肉用种蛋得出失重率为１２％～１３％,罗斯蛋用种蛋失重率为１３．６４％。笔者通过对伊莎褐种蛋在孵化期间失重率的研究探索了种蛋在孵化期间的失重规律。 一、材料和方法 １．实验材料 ＪＷ－１０８００型孵化… 相似文献
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张会刚 《河南畜牧兽医(综合版)》2007,28(3)
在孵化过程中种蛋的失重与气室变化会直接影响孵化率。而影响种蛋失重和气室变化的因素主要是孵化过程中的温度和湿度。为了提高种蛋的孵化率,通过试验探索藏鸡种蛋在孵化过程中的失重与气室变化符合胚胎发育的正常规律。在温度1～6天为37.58℃、7～14天为37.56℃、15～20天37.50℃、21天37.40℃;相对湿度1～6天为60.12%、7～14天为60.36%、15～20天61.12%、21天62.33%时,在整个孵化期中藏鸡种蛋的失重平均在11.58%,气室5～11天倾斜度逐渐增加,11～18天倾斜度比较明显,到了17～18天气室达到最大的倾斜度。 相似文献
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孵化期不同阶段对黄鬃鹅229枚种蛋进行称重,探讨孵化期种蛋失重规律及其与蛋重间的关系。结果表明：黄鬃鹅种蛋孵化期平均失重率为11．95％;0-7胚龄的相对失重率为2．51％;8～18胚龄失重速度增加,相对失重率达4．20％;孵化后期失重速度最快,19～28胚龄的相对失重率达5．74％;而孵化期各阶段蛋重与19—28胚龄相对失重率呈显著负相关（P〈0．05）,相关性随胚龄增加而增强,说明入孵蛋重对孵化后期失重率有影响;死胚蛋失重率较正常蛋显著偏高,但蛋重不是造成死胚蛋失重率偏高的根本原因。 相似文献
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孵化期不同阶段对黄鬃鹅229枚种蛋进行称重．探讨孵化期种蛋失重规律及其与蛋重间关系。结果表明：黄鬃鹅种蛋孵化期平均失重率为11．95％;0～7胚龄的相对失重率为2．51％;8～18胚龄失重速度增加,相对失重率达4．20％;孵化后期失重速度最快,19-28胚龄的相对失重率达5．74％;而孵化期各阶段蛋重与19-28胚龄相对失重率呈显著负相关（P〈0．05）,相关性随胚龄增加而增强,说明入孵蛋重对孵化后期失重率有影响;死胚蛋失重率较正常蛋显著偏高,但蛋重不是造成死胚蛋失重率偏高的根本原因。 相似文献
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藏鸡种蛋在孵化过程中的失重与气室变化符合胚胎发育的正常规律熏即温度1～6d为37.58℃、7～14d为37.56℃、15～20d为37.5℃、21d为37.4℃;相对湿度1～6d为60.12%、7～14d为60.36%、15～20d为61.12%、21d为62.33%时,在整个孵化期中藏鸡种蛋的失重平均在11.58%,气室5～11d倾斜度逐渐增加,11～18d倾斜度比较明显,到了17～18d气室达到最大的倾斜度。 相似文献
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控制种蛋在孵化期间的失水多少是取得最佳孵化成绩的一个必要条件，影响孵化期间种蛋水分失重的因素包括：孵化器湿度控制、孵化厅内湿度、季节、种鸡周龄、蛋重、蛋壳质量以及蛋壳孔隙率等，其中孵化器的相对湿度对种蛋水分失重的影响最大。孵化期间对种蛋定期称重是生产高质量雏鸡的一个很好的质量控制程序。一、相对湿度高对孵化的影响相对湿度高，１８天照蛋时气室小，气室最低边缘在蛋壳最粗处的上端。雏鸡肚子大，脐环愈合不良，雏鸡与蛋白粘连；因失水少，雏鸡出壳时用力较大，跗关节红肿。死胚蛋较多，啄壳部位偏上，因气室小，氧气… 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