即时浸酸蚕种冷藏期限的研究

新九×7532、9·芙×7·湘蚕种即时浸酸后置于有NaCl溶液的缸中保护,冷藏时间90天,实用孵化率保持在88％以上,冷藏至120天,其实用孵化率仍不低于85％。9·芙×7·湘蚕种即浸后冷藏至140天的养蚕结果,孵化率为80％左右,稚蚕发育不够齐一,全茧量、茧层量、茧层率略低于正常冷藏的蚕种。对即浸冷藏期不同的蚕卵进行生化分析,粗脂肪、山梨醇和蛋白质含量均随着冷藏天数增加而下降,但降幅均低于常规冷藏的蚕种。     

提高冷藏浸酸蚕种质量的措施

<正>冷藏浸酸工作是蚕种生产、经营活动中不可或缺的重要环节,既是蚕种成品化的过程,又在一定程度上影响蚕种质量。冷藏浸酸工作季节性强、技术处理复杂,工作中稍有疏忽不慎,会造成蚕种孵化不齐、孵化率降低,给种场和农村蚕茧生产带来损失。随着蚕种冷藏浸酸技术的进步,最近十多年来,江苏秋用冷藏浸酸种的孵化率一直稳定在较高水平,平均实用孵化率达到98％以上,基本达到了蚕农满意,种场放心。实践证明,目前蚕种冷藏浸酸技术符合江苏蚕桑生产的实际,能满足蚕种的有效供应。     

春夏兼用蚕种冷藏方法的探讨

本文介绍了一种新的春制春、夏兼用种的冷藏试验方法，有利于孵化率的提高和简化入库手续，提高蚕种生产的安全性。     

冷藏浸酸种再冷藏的试验

冷藏浸酸种浸酸后再冷藏处理,目前生产中规定,最长不超出7天,为研究再冷藏7天以上对蚕种的影响,经两年试验发现,中间温度保持6小时以上,再冷藏7～25天,蚕种实用孵化率一般都在97％以上,死卵率最高不到1％。并据蚁蚕饥饿死亡调查结果分析,冷藏后对幼虫的饲养成绩不会有大的影响。     

冷藏浸酸种提前出库的可行性试验

本试验研究了冷藏浸酸种提前出库的可行性。结果认为：冷藏浸酸种冷藏60天后是可以出库的，2日实用孵化率可达90％以上。在浸酸时应恰当的加大刺激量，以提高蚕种孵化率。     

冷藏浸酸种提前出库浸酸的试验

本试验通过对预定冷藏100日的蚕种,设定冷藏55日、60日、65日、70日、75日、80日、85日、90日、95日、100日(对照)后分别出库,并用三种盐酸标准浸酸,进行常规催青,调查实用孵化率,试验结果表明:比预定出库日期提前30日～35日的蚕种,可提高提前出库蚕种的实用孵化率,实用孵化率达到90%以上,在生产上对调剂蚕种具有现实意义。     

严格管理 加快改造——提高冷浸种日浸酸量和质量

<正>目前蚕种生产和用种矛盾日益突出,主要表现在两个方面:一是蚕种安全冷藏浸酸日期,与农村用种日期,时间非常接近,中秋用种浸酸速度跟不上;二是农村中秋蚕种质量事故时有发生,孵化率不稳定.针对这些特点,我们进行了积极大胆的探索,深化改革,加强管理,加快技术改造,把好蚕种入库、冷藏、浸酸、配发关,在提高日浸酸量和质量上下功夫,经过3年的摸索,日浸酸量提高到4万多张,基本满足了中秋用种的需要,质量也明显的提高,1994年农村中秋蚕种孵化率在97%以上,其余的孵化率都在95%以上.我们的做法主要有以下几个方面:     

提高早秋冷藏浸酸种孵化率的几点思考

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…     

9·芙赤豆色卵的入库冷藏期限与浸酸孵化效果的关联分析

将产后经过72h的9·芙、芙·9蚕卵入库冷藏,在冷藏经过15～60天期间,可依冷藏时间的长短采取不同的浸酸时间让其孵化;冷藏15天的浸酸7～9min,冷藏45～60天的浸酸3～5min,实用孵化率可达到95%以上。冷藏超过60天后,蚕种直接出库催青便可孵化。经过120～135天冷藏的蚕种,孵化率仍保持在95%以上,但冷藏期超过150天,孵化率开始下降并出现死卵。     

关于复式冷藏蚕种冷藏期限与孵化率的关系

<正> 我省越年蚕种根据蚕种供需情况,大部分采用中间补正冷藏法,作为春用种;另外,将一部分秋制种采用复式冷藏法,作为夏用种。近十年来,为便于蚕种计划调度,以减少蚕种损失,还将部分复式冷藏种推迟至7月甚至8月上旬出库,作为早秋用种。但由于冷藏期延长,影响孵化率,冷藏期越长,孵化率越低。为了进一步探讨不同冷藏期限对复式种各品种孵化率的影响,我们对现行5对品种作了调查,每品种分若干样本,每个样本秤蚕卵1克,从5月25日起至9月5日止,每品种间隔10天出库1个样本,置于25～27.5℃中保护。然后逐次调查各品种的实用孵化率和普通孵化率(由于两     

Factors related to shell deaths during artificial incubation of ostrich eggs

The ostrich industry experiences a high rate of embryonic mortalities during artificial incubation of eggs. Embryonic deaths were studied from data recorded on 37,740 fertile eggs incubated artificially during the 1998-2005 breeding seasons. Roughly 10,000 eggs that sustained embryonic mortalities were classified according to the stage and nature of death, i.e. before 21 days of incubation, after 21 days of incubation, deaths after pipping and rotten eggs. Although infection may have played a role in approximately 1300 rotten eggs, no detailed knowledge of the pathogens involved was available. The remainder of deaths could not be related to pathogens and the deaths were thus generally referred to as non-infectious. The overall level of embryonic mortality in all the eggs studied was 28.5 %. Overall embryonic mortality was affected by incubator, with higher levels (57.0 %) found in eggs incubated in an African Incubator and also in eggs that were transferred between incubators during incubation (38.1%). Overall embryonic mortality also increased in eggs produced by older females. Eggs produced in the autumn had the highest level of embryonic mortality at 53.6 %, whereas eggs produced in the winter had a marginally higher level of embryonic mortalities of 29.2 % compared with eggs produced during summer (27.4 %). Eggs produced by South African (SA) Black males crossed to Zimbabwean Blue females had high levels of embryonic losses of 45.7 %. The embryonic mortality of eggs produced by SA Blacks or Zimbabwean Blue breeding birds subjected to pure breeding was similar at approximately 33-34 %, but embryonic mortality was improved in eggs produced by Zimbabwean Blue males crossed to SA Black females (27 %). Embryonic mortality was increased in eggs that were set directly (32.0 %) or subjected to longer than 6 days of storage (43.5 %). Embryonic mortality was affected by year. The results that were obtained will assist in determining non-infectious factors that have a negative effect on hatching success. Steps can thus be taken to eliminate such factors that may compromise hatching success.     

Effects of setting eggs small end up on hatchability and posthatching performance of broilers

1. Hatchability of fertile eggs incubated with their small ends up (SEU) was 16 to 27% lower than for eggs set with their large ends up (LEU). In addition, the SEU position produced more nonviable chicks. 2. There were no differences in post-hatching performance between the two incubation treatments. 3. A survey in a commercial hatchery revealed that the frequencies of eggs set upside down by mistake varied from 0.3% to 3.4%. The setting of eggs upside down was attributed not to difficulties in distinguishing the large and small ends of the eggs but to human error. A decrease in the number of Grade-A chicks of about 0.2% was observed for every 1% of eggs set upside down, suggesting it may be of economic importance to ensure that the eggs are set properly with their large ends up.     

The overwintering of Fasciola hepatica eggs under semi-arid and temperate Mediterranean climate (Madrid, Spain).

In this experimental work, conducted over two consecutive years (1988 and 1989), we have analyzed the overwintering possibilities of Fasciola hepatica eggs deposited in winter in a semi-arid and temperate Mediterranean area (Madrid, Spain). Eggs did not survive for more than a week in faeces at environmental moisture conditions. In contrast, over a 75% of the eggs maintained in permanently wet faeces survived winter temperatures, showing no high mortality until important thermic increment from June. The success of overwintering was higher in eggs arrested in wet faeces than included in water (55% "versus" 20% of hatching in spring), and it was unrelated to the deposition time (excretion in early or late winter). The hatching period of overwintered eggs started in May, at the same time as those excreted in early spring. Therefore, overwintering of eggs will have an effect on the level but not on the start of the spring contamination with miracidia. The dry winters of this semi-arid area greatly restrict the overwintering eggs contamination to soils next to streams, ponds or irrigation channels.     

全国桑蚕一代杂交种质量调查及行业标准实施评价Ⅰ.春用一代杂交种总体质量及评价

连续 5年对全国主产省 (市、区 )的蚕种进行了质量监督抽检 ,检验结果表明 :我国春用桑蚕一代杂交种总体质量良好 ,蚕种质量逐年稳步上升。分析桑蚕一代杂交种总体质量及各指标的测试成绩后认为 :散卵种良卵率≥ 97%、杂交率≥ 95 %、病卵率 <0 15 %的指标比较合理 ,而平附种良卵率≥ 90 %的指标偏低 ,可提高到 94 %～95 % ;实用孵化率≥ 90 %的指标偏低 ,可提高到 92 %以上 ;良卵 (粒 )数指标可改为规定下限 ,如每盒蚕种不少于多少粒 ,允许有不同的卵量 ;蚕种外观包装的标签上还可添加注册商标、执行标准、良卵 (粒 )数 ,春用种须标明出库日期、夏秋用种还须标明浸酸日期等。     

全国桑蚕一代杂交种质量调查及行业标准实施评价Ⅱ.良卵率、良卵数调查及评价

依据 1999- 2 0 0 3年监督抽查春用桑蚕一代杂交种质量的检验结果 ,分析良卵率和良卵数质量指标的测试成绩认为 :散卵种良卵率≥ 97%的指标比较合理 ,而平附种良卵率≥ 90 %的指标偏低 ,可提高到 94 %～ 95 % ;良卵数 (粒 ) /盒 (张 )连续 5年合格率都在 5 0 %以下 ,说明这一指标不适合目前的生产情况 ,可考虑将这一指标改为规定下限 ,允许有不同的卵量。     

生物保健型蛋白饲料对蛋品质影响的试验研究

选择320日龄海兰褐蛋鸡234只,共分A(对照组)、B、C3个处理组,采用生物保健型蛋白饲料(SBD)代替蛋鸡日粮中的部分豆饼,通过56d的饲喂试验。结果表明:用3%生物保健型蛋白饲料代替日粮中3%的豆饼时,平均蛋重、产蛋率、破软蛋率、采食量都与对照组无显著差异(P>0.05);用5%生物保健型蛋白饲料取代饲粮中5%的豆饼时,平均蛋重、破软蛋率、与对照组无显著差异(P>0.05),但产蛋率、采食量与对照组相比均有下降(P>0.01),在蛋的品质方面未产生不良影响,只是C组的蛋黄颜色比A、B组偏黄,铜(Cu)的含量偏高。由此可见采用生物保健型蛋白饲料代替蛋鸡日粮中3%的豆饼,效果最佳。     

Egg shell colour is affected by laying cage design

1. When laying hens are stressed some retain their eggs in the shell gland beyond the normal time of laying and this can result in the deposition of extra-cuticular calcium which makes brown eggs appear paler. 2. Three different types of enriched modified cage were compared: the location where eggs were laid was recorded and shell colour was measured using a reflectometer. 3. In 2 types of cage with enclosed nest boxes more eggs (80%) were laid in the nests than in a design with nest hollows in the open part of the cage (41%). 4. The eggs from the cages with enclosed nests were darker (had less extraneous calcium) than those with open nest hollows. This implies that in the designs with nest boxes fewer eggs had been retained and the hens may have been less stressed. 5. The results support previous evidence that to reduce stress and improve welfare it is desirable to provide enclosed nest sites for caged laying hens.     

Development in culture of the chick embryo from cleavage to hatch

1. Early uterine embryos were obtained from hens by induced oviposition 7.5-8.0 h after the preceding egg was laid. They were cultured in vitro and then in recipient shells to hatch. As controls, embryos from freshly laid eggs were cultured in recipient shells to hatch. 2. For embryos cultured from uterine eggs, the hatch rate was 22.5%, and for embryos cultured from laid eggs, the hatch rate was 62.5%. 3. The weight of the chicks hatched from culture was about 60% of the weight of the preceding egg, or donor egg. Male and female chicks reached maturity and have produced viable offsprings. 4. The results show that it is possible to grow chick embryos in culture from the early cleavage stage (stage II) to hatch. They extend earlier findings on the culture of embryos from the blastoderm stage (Stage X) to hatch. The technique provides a basis for investigations on chick embryo cryopreservation.     

家蚕有滞育多化性品种滞育卵复式冷藏继代法的研究

利用上年中秋制种的滞育卵经复式冷藏处理,到当年夏蚕期饲养,夏制种再经中秋蚕期饲养,进行了有滞育多化性品种的省力保种试验.夏蚕期其生命力较对照组低1.2%~1.9%,生种率上升16.0%,差异达显著程度.中秋蚕期生命力高1.0%,生种率低0.9%,完全恢复正常.重复试验,结果一致.有滞育多化性品种用滞育卵复式冷藏处理一年二次省力保种是可行的.     

Characteristics of oviposition patterns of turkey hens and the influence of different wavelengths of light

1. Characteristics of individual oviposition patterns of turkey breeder hens were determined for 160 d of photostimulation with fluorescent blue, green or red light and with incandescent light. 2. In all treatments most eggs were laid during the afternoon and evening. The maximum frequency occurred at 14.00 to 15.00 h (8 to 9 h after light onset); about 15% of all eggs were laid in the dark period. 3. The hourly oviposition distribution remained unchanged and was specific to individual hens throughout the study period. However, it was highly variable between hens, ranging from highly dispersed to tightly clustered. 4. The total number of clutches per hen did not differ between treatments and eggs were laid in relatively short clutches; 65% were of two eggs or fewer, 30% of three to 5 eggs and only 5% of 6 eggs or more. 5. The oviposition time of the first egg in a clutch was very variable; however, oviposition time became more clustered and uniform as the position of the egg in a clutch increased. 6. Mean time of lay, mean interval between eggs and total lag time were not influenced by light treatment. Mean interval was about 27 h for all eggs and was not influenced by clutch size. 7. Light quality at the intensity used in this study did not appear to play an important role in oviposition patterns of turkey hens.