性激素在蚕种生产上的应用初探

本试验利用体喷雌二醇和睾丸酮于雌、雄蚕蛾,观察外源性性激素对家蚕产卵速度、交配速度以及卵质量的影响。结果表明:性激素处理后,能显著提高蚕蛾产卵速度,投蛾3小时内的产卵量以雄激素处理雌蛾最显著,较对照组增加4.2倍(P<0.05),雌激素处理雌蛾则增加3.6倍(P<0.05);而雌、雄激素处理雄蛾则分别较对照组增加2.8倍和2.0倍(P>0.05)。结果还表明性激素处理使交配成对率显著提高,雌激素处理雌蛾,15分钟成对率达100%,雄激素处理雄蛾10分钟后基本都已成对,显著高于对照组;余二组亦有不同程度的提高。试验调查还表明性激素处理蚕蛾,所产卵的孵化率及蚁蚕的生命率与对照组无差异,说明性激素不影响蚕卵质量,并且具有降低不受精卵率的作用。     

蛹蛾期不同冷藏处理对桂蚕二号亲本产卵的影响

为明确家蚕原种生产中蛹蛾期最佳低温保护法,调查了桂蚕二号（8810·932）×（8711·7532）4个亲本在蛹期和蛾期冷藏对不受精卵率和良卵率的影响,结果表明：桂蚕二号各亲本品种在蛹期和蛾期不同冷藏处理,其不受精卵率和良卵率在处理间的差异都达到显著性水平。试验证实8810的雌蛾不宜冷藏;932在雌蛹触肢着色期不宜冷藏...     

不同成熟度雌蛾交配对产卵和受精的影响

2010年以来利用三个春季制种期对不同成熟度菁松雌蛾交配产卵情况及受精情况进行了试验调查。A、B、C所代表的三类不同成熟度的雌蛾,尽管所交配用的皓月雄蛾成熟新鲜度相近,交配时间相同,交配环境条件一致,但蚕卵产出率及不受精卵率相差较大。只有发育成熟的母蛾交配产卵,才能增加单蛾的产卵量,降低不受精卵率。     

不同的交配时间，产卵期的明暗与母蛾产卵快慢及产卵量的关系

对家蚕“两广二号”正交（芙·9×湘·7）品种的雌蛾在产卵期提供明暗两种处理的对比试验,结果：暗产卵的速度总是比明产卵的快且集中,如在交配5小时的黑暗条件下,产卵最快且集中,4小时内产卵量达87．61％,6小时内产卵量达97．89％;而明亮条件下,4小时内产卵40．72％,6小时内产卵83．10％。在较短的时间内集中产卵有利于提高蚕种的一日孵化率。另外,各处理在明、暗条件下,对单蛾产卵量、不受精卵率的发生影响不是很大,但不同的交配时间处理对卵量有显著的差异,对不受精卵的发生有极显著的差异。     

家蚕蛹期不同温度保护对产卵量及不受精卵的影响

以云蚕7、云蚕8为试验材料,调查分析蛹期不同温度保护对蚕种产质量的影响,蛹期遭遇28℃以上高温,会使不产卵母蛾、少产卵母蛾增多,不受精卵增加,良卵率降低,不受精卵率和生种百分率增高,影响蚕种产量和质量。     

冷藏雌雄蛾对雌蛾产卵的影响

通过对雌雄蛾冷藏不同时间的处理,调查雌蛾产卵情况,结果表明雄蛾冷藏3d内、雌蛾冷藏1d对蚕种和制种无显著影响,雌蛾冷藏2d不受精卵率、遗腹卵率都达到差异极显著水平。     

防僵粉消毒蛹体对蚕种生产的影响

用中国系统种夏芳原蚕蛹为材料,在化蛹后第6、7、8、9天分别用防僵粉(含有效氯2.5%)对蛹体进行消毒,调查其发蛾率、母蛾产卵量、良卵率,结果表明:用防僵粉消毒蛹体对发蛾率、母蛾产卵量、良卵率均有较大不良影响.     

桑蚕雌蛹后期冷藏处理的效果试验

通过桑蚕日系(7·湘)和中系(9·芙)的雌蛹后期不同冷藏时间与发蛾率、产卵量及不受精卵率关系的试验,结果表明:随着雌蛹冷藏天数的增加,有发蛾率逐渐降低、产卵量逐渐减少、不受精卵率逐渐增加的趋势,但日系蛹冷藏2天以内,中系冷藏3天以内不明显;日系冷藏3～6天,中系冷藏4～6天,这种趋势非常明显。     

产卵环境与母蛾干湿状态对不受精卵发生的影响

产卵环境湿度大,母蛾被蛾尿沾湿则两广二号反交种的不受精卵率增高;母蛾干燥,产卵环境干燥,则不受精卵率降低。     

产卵湿度环境对“两广二号”反交种不受精卵率的影响

产卵环境湿度大,母蛾被蛾尿沾湿,则“两广二号”反交种的不受精卵率增高;母蛾干燥,产卵环境干燥,则不受精卵率降低。     

Effect of temperature on transovarial transmission of Babesia bigemina (Smith and Kilborne, 1893) in Boophilus annulatus (Say, 1821)

The effect of the temperature on the transovarial passage of Babesia bigemina has been studied in female Boophilus annulatus during their oviposition. Kinetes of Babesia were present in eggs laid at the temperatures of 16, 20, 26, 28, 30 and 35 degrees C. The rate of infection was temperature dependent. It reached at least 50%, even at low temperatures. The average infection level at 26 and 30 degrees C was 270 kinetes per egg. However, between 20 and 35 degrees C the eggs laid during the first 3 days were parasite free. At 16 degrees C, no kinetes were detected during the first 13 days of oviposition.     

The life cycle of Rhipicephalus bursa Canestrini and Fanzago, 1877 (Acarina: ixodidae) under laboratory conditions

The biology of Rhipicephalus bursa has not been thoroughly studied. In the present study R. bursa was bred in the laboratory and its biology worked out.Larvae, nymphs and adult Rhipicephalus bursa ticks were fed on sheep and were held at 28+/-1 degrees C and 89+/-1% relative humidity (RH) in a darkened incubator. The average weight of engorged females was 0.676g (range 0.353-1.128). The average weight of eggs laid by females was 0.344g (range 0.146-0. 554g). The average number of eggs laid was 7527 (range 6263-8860) and this was significantly correlated with the weight of the females. The index of Reproduction Efficiency (number of eggs per g weight of female) was 8469.6. The index of Conversion Efficiency (weight of eggs per weight of female) was 0.5037.Peak daily oviposition, at an average of 840 eggs per female, occurred on the 6th day of oviposition. After Day 6, the rate declined steadily. The average duration of the preoviposition period was 5.1 days (range 4-7 days). The oviposition period averaged 16.5 days (range 12-21 days), and was significantly related to both the weight of the female and the number of eggs laid. The average pre-hatching period was 31.2 days (range 24-45 days). The average feeding time of larvae and nymphs of this two host tick was 15.2 days (range 14-18 days). Female ticks fed for 5.9 days on the average.Heavier nymphs produced females and a shorter premoult period was noted for lighter male nymphs. The males/females ratio was 1.38:1. The time taken to complete the life cycle was on average 142.45 days (range 99-254 days).     

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.     

野蚕越冬卵的孵化和年发生代数的研究

研究证实(1980—1984年),嘉湖平原野蚕年发生三代.越冬卵始孵期为四月中旬,盛期为六月中旬.但近半个世纪以来.很多人一直误认为四月中旬发生的野蚕是第一代,六月下旬发生的为“第二代”,事实上都是越冬卵孵化的幼虫.均为第一代.经测定,四月下旬越冬卵孵化率为0.15%,5月下旬为7.9%,6日20日为91%.本区野蚕产越冬卵最的早在9月17日,高峰期在11月上旬.结束期在12月14日,越冬卵产出越早,翌年卵孵期也早,孵化的早和迟之间可相差122天.野蚕越冬卵翌年孵化期长的原因.与秋冬产卵期长及桑园生态环境复杂有关.据室内4月24日越冬卵孵化的幼虫连续饲养,到第三代卵期恰与室外第二代卵期相重叠,说明自然界发生第四代是可能的,但真正存活率在1%以下.在防治措施上,以在越冬卵孵化高峰期(6月15—20日)施用0.1%敌敌畏.防效最好.     

Oviposition and incubation in Boophilus decoloratus (Koch, 1844) (Acarina: Ixodidae)

Studies on the duration of the oviposition and incubation periods of Boophilus decoloratus (Koch, 1844) revealed that these non-parasitic periods are temperature dependent, increase in temperature causing shortening of the periods. Humidity had no effect on duration of either the oviposition or the incubation periods. The relation between the mass of engorged female ticks and that of the eggs they produced was found to be linear. The viability of eggs produced during the first 13 days of oviposition (at 26 degrees C) was greater than that of eggs laid subsequently. The critical temperature for B. decoloratus eggs was found to be 42 degrees C and they were shown to be unable to take up water vapour from damp atmospheres. Both temperature and humidity affected the hatch of eggs. A simple model of the relations between the physical factors of the environment and the various biological phenomena studied has been given.     

数种驱虫药和化学药物对体内外鸡蛔虫产卵和虫卵发育的影响

为鉴定男性不育药和有些驱虫药对寄生蠕虫的不育作用,对培养在试管内的鸡蛔虫和卵胚,以及人工感染蛔虫的鸡分别进行了体内和体外试验。棉酚和硝基呋喃类的呋喃唑酮、呋喃西林、S_(73031)和S_(72055)均无抑制产卵和卵胚发育的作用,苯并咪唑类的丙硫咪唑、甲苯咪唑和噻苯咪唑以及吩噻嗪均有抑制产卵和卵胚发育的作用,它们的EMIC_(50)分别为0.006,1.326,0.029和0.052ppm。抑制产卵所需浓度远大于抑制卵胚发育所需浓度。吡喹酮和硫双二氯酚也不具有抑制产卵和卵胚成熟的作用。放线菌酮仅对试管内蛔虫有抑制产卵作用,但对体内蛔虫却无影响。     

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.     

Development of Hyalomma lusitanicum under laboratory conditions

At the constant temperature of 25 degrees C and relative humidity (RH) of 84%, the average pre-oviposition period of Hyalomma lusitanicum was 47 days, the oviposition lasted an average of 26 days and the total egg production was an average of 6320 per female. At 16 degrees C the females did not lay eggs at all, but those which survived for 1 year and were transferred thereafter to 25 degrees C and 84% RH laid viable eggs. At 35 degrees C, the oviposition was identical at all levels of RH tested (25, 62 and 93%). At 25 degrees C, the pre-oviposition period was shorter at 93% RH, and the number of eggs laid was fewer at 25% RH. The eggs hatched in 32-40 days, the hatching percentage being lower in batches of eggs laid at the beginning and at the end of the oviposition period. The larval and nymphal moultings were not influenced by the type of host. As the temperature increased, the pre-moult period became shorter. The engorged larvae were more sensitive to the low RH than the engorged nymphs, whose moulting percentage was always greater than 72 in all regimes. Low temperature and high humidity had a favourable effect on the survival of unfed nymphs. The female-to-male ratio was 1:2. Hyalomma lusitanicum always behaved as a 3-host tick. The adults did not engorge on rabbits. The female ticks engorged on calves weighed an average 543 mg. Ticks maintained at 25 degrees C and 84% RH and engorged on calves completed the life cycle in 138-196 days, which does not include the period of chitinization of about 30 days. More than half of this period was spent in egg laying and hatching.     

Effect of infection by Babesia spp. on the development and survival of free-living stages of Boophilus annulatus

Oviposition, egg hatching and survival of newly-hatched larvae of Boophilus annulatus were studied in relation to infection by Babesia species and different temperature regimens. Infection of female ticks by Babesia bigemina or B. bovis had no effect on the time elapsed between engorgement and oviposition. The duration of oviposition was shorter in infected females incubated at 25 degrees C or 35 degrees C and infected females laid fewer eggs than the controls. No larvae hatched at 16 degrees C. B. bigemina-infected eggs hatched more quickly than uninfected eggs at 35 degrees C. The hatching percentage of B. bigemina-infected eggs was reduced by 50% at an incubation temperature of 25 degrees C and by 75% at 35 degrees C. At 16 degrees C there was no difference in the duration of survival of infected and non-infected larvae but at 25 degrees C and 35 degrees C the mean survival period of infected larvae was significantly lower than those of controls.     

矮小型褐壳蛋鸡产蛋时间和间隔的统计分析

本文对８８０只纯系矮小型褐壳蛋鸡的产蛋时间进行了连续５天的观察,分析结果表明,矮小型褐壳蛋鸡的产蛋时间集中在上午１２时以前,并以９：００～１０：００期间产蛋最为密集,占全天产蛋的１９．５％。连产内第一枚蛋产出时间集中在上午（８９：３３％）,以７：００～９：００间产蛋最多（４９．７１％）;而最后一枚蛋产出时间集中在下午（７１．２０％）,以２：００～４：００间产蛋最多（３６．５８％）。矮小型褐壳蛋鸡连产内产蛋间隔范围为２２．３５～３１．１５小时,每枚蛋平均间隔高峰在２４小时（３６．０％）,群体平均产蛋间隔为２５．０８小时。相邻连产间间隔时间的变异范围很大,最短为３８．０小时,最长达１００．４５小时。