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Earthworms form an important component of the soil biota in many soils and are very sensitive to various types of contaminants. Their protection may therefore provide a margin of safety for other fauna once comparative toxicological data are available. The effects oflead on growth, maturation, cocoon viability and cocoon production of the vermicomposting earthworm species Eisenia fetida were studied by exposing worms experimentally to a sublethal concentration of lead (2000 µg. g?1) for a period of 76 days. Growth rate as well as cocoon production were monitored every 14 days and cocoons were incubated to determine their hatching success. Lead content of worms was also analysed. Exposed worms grew noticably better and produced more cocoons than control worms. Cocoon viability was, however, affected detrimentally. It is concluded that, although lead is known to be toxic at higher concentrations, sublethal concentrations close to the predicted EC5a and NOEC-values have a stimulating or hormetic effect on growth and cocoon production. 相似文献
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To determine the full potential of the compost worm Eisenia fetida as waste processor and as source of protein, the life-cycle of this species had to be studied thoroughly. The development, growth and reproduction of Eisenia fetida were studied on cattle manure under favourable conditions of moisture, temperature and nutrition. Data were gathered over a period of 600 days. Apart from the life-cycle this study also indicated that this species can be reproductively active for more than 500 days. This is significantly longer than had previously been believed. Each cocoon produced a mean of 2,7 hatchlings after a mean incubation period of 23 days. These worms attained sexual maturity after 40 to 60 days and produced their first cocoons within four days after mating took place. 相似文献
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柞蚕多丝量新品种方山黄2号育成 总被引：1，自引：0，他引：1
以方山黄为亲本材料,采用系统选育法,经过5年10代的选择与培育,育成了柞蚕二代性、多丝量新品种方山黄2号。实验室秋茧平均茧层量1．49g,茧层率16.61％。农村中试成绩茧层率为15．65％,鲜茧出丝率9．42％,经过3年的生产鉴定,方山黄2号孵化率在95％以上,幼虫生命率97％以上,公斤卵产茧量比方山黄增产15％以上。 相似文献
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利用杂交育种及系统选择的方法,育成了具有中细纤度特色的4眠性家蚕新品种苏秀×春丰。经江苏省家蚕新品种实验室鉴定和农村生产试验表明,新品种孵化、眠起、上蔟齐一。实验室鉴定成绩为万蚕茧层量、万蚕产丝量分别比对照品种菁松×皓月提高1.02%和1.28%,茧丝品质性状也优于对照品种,其中茧丝长1525m,解舒丝长1186m,解舒率77.78%,茧丝纤度2.646dtex,洁净93.94分。新品种具有茧丝纤度细、茧丝长、茧丝纤度综合均方差小的特色,适合缫制细纤度高品位生丝。2010年4月该品种通过江苏省蚕品种审定委员会审定,可作为华东地区优质原料茧生产的实用家蚕品种。 相似文献
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根据长江流域夏秋季的气候特点,采用杂交、回交、系统分离、活蛹缫丝和多代高温多湿环境定向培育等育种方法,分别育成了中系蚕品种“浒花”和日系蚕品种“秋星”。两者都具有抗性强、丝量高、茧丝质优以及繁育容易等特点。其一代杂交种经多次实验室鉴定、农村生产鉴定、试养以及全国蚕品种审定结果表明:该新品种体质强健、孵化、眠起、老熟齐一,茧丝量高,茧层率22％;鲜毛茧出丝率15—16％,茧丝品质优良、解舒率74％,净度93分,茧丝纤度2.53/D,茧丝长超1000m。 相似文献
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菁松×皓月是生产上推广量最大的春用多丝量家蚕品种,根据家蚕茧荧光色的遗传机制,将该品种改育成具有蚕茧荧光显色判性性状的品种。对蚕茧有多种荧光显色的菁松通过系统分离方法,对蚕茧单一荧光显色的皓月通过杂交导入荧光伴性基因Fx及定向培育的方法,将2个品种均改育成雄蚕茧为黄荧光色、雌蚕茧为紫荧光色的品种,其荧光判性准确率达到100%。2个改育的品种暂命名为苏杰、豪胜。实验室饲养鉴定成绩表明改育品种杂交组合苏杰×豪胜的幼虫比菁松×皓月发育快,体质更强健,但全茧量略低;缫丝鉴定苏杰×豪胜的茧丝纤度2.686 dtex,洁净95.5分,茧丝长1 300 m以上,解舒率75%以上,并且生丝匀度好。改育品种杂交组合苏杰×豪胜的主要经济性状成绩与菁松×皓月相仿,在生产上推广应用可以达到雌雄蚕茧分别缫丝和提高蚕种制造鉴蛹工效的目的。 相似文献
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Michel Mathurin KAMDEM Albert NGAKOU Nicolas YANOU NJINTANG Patricks VOUA OTOMO 《Integrative zoology》2021,16(2):255-269
The ingestion of organic and mineral materials by earthworms is a prominent functional role that has profound consequences for the decomposition and stabilization of soil organic matter. To investigate the litter consumption of the African nightcrawler earthworm Eudrilus eugeniae under different tropical conditions, we used DNA barcoding to identify specimens of E. eugeniae collected from sites across the Adamawa region in Cameroon, and studied the influence of habitat suitability (soil properties), soil moisture, litter type, and population density on litter consumption. A total of four litter consumption experiments were carried out using soils collected from refuse disposal sites, agricultural lands, and savannahs dominated by the Mexican sunflower Tithonia diversifolia. The results revealed that litter consumption significantly increased in the refuse disposal and agricultural soils as opposed to the Mexican sunflower (T. diversifolia) soil, a cow dung enriched substrate, and a sterile soil horizon from the savannah (P < 0.05). The optimum moistures for litter consumption were between 24% and 50%. Litter type did not affect the consumption rate of the earthworms (P > 0.05). We observed a general positive density-dependent consumption with litter mass loss increasing with increasing density. Our results suggest that E. eugeniae has a strong direct effect on the decomposition of plant materials than expected from previous estimations, and that litter consumption rates are determined by several habitat components and population density. 相似文献
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对SM-1诱导3眠蚕茧(4·SM-1和3·SN-1)和对照区4眠蚕茧的解舒和茧丝物理性质进行比较研究的结果表明,4·SM-1,3·SM-1和对照区的茧丝乎均纤度分别为 1.29D、2.04D和2.59D,蚕丝纤度均方差不匀率分别为9%、12%和19%.随着茧丝纤度变细,扬氏模量和强度增加,但茧丝纤度小于1D时,强力有减小的趋势.从解既看.诱导的三眠蚕茧丝离解时,离解张力的变化幅度小.频率大,解舒率明显优于4眠蚕茧.根据上述性质可以认为,SM-1诱导3眠蚕茧是生产特别高匀度的细纤度生终以及特殊纤维的理想原料. 相似文献
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二化一放蚕区柞蚕杂交种呼伦贝尔一号的选育 总被引：1，自引：0，他引：1
采用系统分离和杂交育种方法,育成了适合二化一放蚕区(主要为高寒地区)放养的柞蚕四元杂交新品种呼伦贝尔一号。经小区试验和农村生产鉴定,主要经济性状均超过对照种,千粒茧重11.24 kg,茧层量1.28 g,平均每把产茧量1461.12 kg,分别比对照种提高8.91%、16.67%和39.87%;茧丝长1246.42 m,解舒丝长656.46 m,分别比对照种增长165.21 m和177.70 m。该品种具有强健好养、产量高、茧丝质优良和适应性强等特点。 相似文献
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Ellakany Hany F. Abuakkada Somaia S. Oda Samah S. El-Sayed Yasser Said 《Tropical animal health and production》2011,43(1):249-257
The present study was conducted to evaluate the adverse effects of an interaction between low levels of dietary aflatoxins
(AF) and Eimeria tenella infection on broiler chicks. A set of 1-day-old chicks were raised for 35 days in the following groups: a control group,
a group fed AF, a group fed AF and inoculated with E. tenella (AF + E.ten), and a group inoculated with E. tenella alone. AF in the contaminated diet were given at 200 ppb starting from the seventh day after hatching while E. tenella was inoculated at a dose of 5 × 104 sporulated oocysts per chick at the 14th day after hatching. Worsened performance traits and high mortality were all observed
in the treated birds, particularly the AF + E.ten group. Lesion scores and oocyst outputs were not different within groups. Chickens fed with AF had significantly increased
serum ALT and ALP activities as well as decreased albumin content. They also showed hepatomegaly, hepatocytic vacuolation
and necrosis, an atrophied bursa of Fabricius, and a thymus with tissue depletion. E. tenella-infected broilers displayed a significant reduction in packed cell volume, hemoglobin content and lymphocyte percentage,
and showed hemorrhagic typhlitis. The deficits in hepatic function and hematologic parameters as well as the gross pathological,
and histopathological changes, were more common and more severe in the group that was exposed to both aflatoxicosis and coccidiosis
than in the groups exposed to either treatment alone. Thus, the combination of aflatoxicosis and E. tenella infection may influence the course of coccidial infection due to additive effects. 相似文献
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家蚕限性褐圆斑品种实用化研究初报 总被引：1，自引：0，他引：1
以优良现行家蚕品种夏芳、871、317、873改良中系限性褐圆斑LC310,回交4代,再用顶交法测定配合力,组配了一对限性褐圆斑实用品种夏芳限×LN010。该品种中系为限性普斑,日系为限性褐圆斑,杂交种为限性褐圆斑,易于进行早期雌雄鉴别。鉴定结果表明其一代杂交种生产性能良好,雄蚕茧全茧量2.00 g,茧层量0.536 g,茧层率26.77%,万蚕收茧量18.99 kg,万蚕茧层量5.07 kg,死笼率1.47%;茧丝长1 324.58 m,解舒丝长1 018.86 m,解舒率76.92%,鲜茧出丝率22.91%。 相似文献
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An experimental investigation revealed that cocoon production by E. foetida (Oligochaeta) increased linearly with increase in temperature in the range 10 to 25 °C. Diurnally fluctuating temperature did not have a marked influence on total cocoon production at the temperature levels of 10, 15 and 25 °C. A highly significant difference in cocoon production occurred between a constant temperature of 20 °C and a mean temperature of 20 °C (which fluctuated diurnally between 12 and 28 °C). Maximum cocoon production was obtained at 25 °C with each worm producing a cocoon every second day. The investigation also showed that temperature does influence the number of hatchlings per cocoon. At a temperature of 25 °C fewer worms hatched per cocoon than at 20 °C. 相似文献
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家蚕荧光茧色的研究——Ⅰ.不同品种的荧光茧色 总被引：1，自引：0，他引：1
在紫外光的照射下,观察了348个品种品系的荧光茧色。结果:白茧品种(1)有白荧光、黄荧光、紫荧光及一些中间色的连续光潜。按系统比较白荧光茧的比率是日系>中系>欧系,黄荧光茧的比率是中系>日系>欧系,紫荧光茧的比率是欧系>中系=日系,按化性白荧光茧的比率是日一化>欧一化>多化>中一化四眠>日二化>中二化>中一化三眠,黄荧光茧的比率是中一化三眠>中二化>日二化>多化>中一化四眠>日一化>欧一化,紫荧光茧的比率是欧一化>日一化>中一化四眠>中一化三眠>多化>日二化>中二化。(2)雌雄茧荧光有明显差异,雄黄荧光茧多且强,雌茧紫荧光多。发现了5个品种雄茧基本上为黄荧光,雌茧为紫荧光。(3)荧光茧色与解舒有关系,解舒率与黄荧光茧呈正相关,与紫荧光茧呈负相关,不同的系统,化性则有所区别。有色茧基本上是黄荧光,也有个别品种茧出现白荧光或紫荧光。 相似文献