家蚕春用品种研究现状及展望

家蚕新品种的选育和应用是蚕丝业科技进步的核心因素,春用蚕品种研究则是这个核心的重点。本文就国内外家蚕春用品种研究的历史、现状及发展方向进行阐述,希望对我国当前的蚕育种工作有所帮助。     

Maternal behaviour and performance in first-parity outdoor sows

When sows and their litters are kept outdoors, much of the responsibility for the litter is shifted from the herdsman to the sow compared to when the sows are kept indoors. Therefore, the maternal ability, including maternal behaviour, is believed to be important in outdoor piglet production. The aim of this study was to describe maternal traits in conventionally bred first-parity sows kept outdoors. Nursing behaviour, sow activity, sow body reserves, litter size and piglet growth were studied in 40 first-parity sows during a seven week long lactation. The sows were kept in groups outdoors. Sow activity (lying down or active) and nursing behaviour (nursing frequency, nursing duration and nursing terminator) were recorded on videotapes at four days post partum (pp) and directly observed at four and six weeks pp. Cross suckling was observed at four and six weeks pp. Sows were weighed and measured for backfat depth five days before farrowing, two weeks pp and at weaning seven weeks pp. Piglets were weighed at four days pp, at two weeks pp and at weaning. We concluded that sow nursing behaviour and activity are individual characteristics repeatable within sows' late lactation. Less active sows are more available for suckling. Light and thin sows have an earlier and more progressed weaning process than heavier, fatter sows. A significant positive relation was found between sow appetite in early lactation and piglet growth until weaning. Sow nursing behaviour is not important for piglet growth when sows and piglets are held in groups, piglets have access to sow feed and piglets are weaned as late as at seven weeks of age.     

夏秋用双限性家蚕品种1303×1302的选育

选用限性基础材料,采用连续回交的育种方法,育成了夏秋用双限性家蚕品种1303、1302。新品种经高温多湿定向选育,抗逆性强,健康好养,万蚕产茧量18.39 kg,茧丝长1180.5 m、解舒丝长968.8 m、解舒率82.04%,鲜茧出丝率17.92%,洁净96.0分。新品种具有可利用幼虫斑纹区分雌雄的特性,可作为生产优质蚕种和雌雄分缫茧丝的专用蚕品种。2005年该品种通过四川省家蚕品种审定委员会审定。     

Effect of restricted suckling on milk yield,milk composition and udder health in cows and behaviour and weight gain in calves,in dual-purpose cattle in the tropics

The study was conducted to evaluate the effects of restricted suckling (RS) in dual-purpose cows and calves compared to artificial rearing (AR). Twelve Holstein-Zebu cows with calves were assigned to each treatment. Cows were milked once daily in the morning with calves present to stimulate milk let-down. RS calves suckled 30 min after milking and 30 min in the afternoon, whereas AR calves were milk-fed from nipple bottles. The daily saleable milk yield was higher in RS than in AR cows (p < 0.01; 7.44 vs 6.50 kg/day), whereas RS cows had lower milk-fat content (p < 0.001). AR cows had higher California Mastitis Test scores (p < 0.001) and lower lactose content (p < 0.001) compared to RS cows, which indicates an improved udder health in RS cows. AR calves displayed more ‘cross-suck’ during suckling/milk feeding (p < 0.001) and during observations of general behaviour (p < 0.05), and more ‘lick and sniff interior’ during milking (p < 0.05) and suckling/milk feeding (p < 0.01), compared to RS calves. During observations of general behaviour the RS calves were more often observed to ‘walk’ (p < 0.01) and ‘lick self’ (p < 0.05) and less frequently to ‘eat concentrate’ (p < 0.05) than AR calves. Results support the hypothesis that RS increases milk yield, influences milk composition and improves udder health in cows, and decreases abnormal sucking in calves.     

桑蚕春用品种贵蚕2号的选育

采用双测交育种方法,育成了强健优质春用蚕品种贵蚕二号（827·渝5×826·渝3）,系四元杂交种。经多次鉴定、农村饲养、试繁结果表明：该品种体质强健好养,制种性能好,茧大而匀,茧丝质良好,综合经济性状优良,四龄万蚕收茧量23．03kg,四龄万蚕茧层量5．86kg,茧成率25．43％,茧丝长1446m,解舒丝长1253m,鲜毛茧出丝率19．93％,净度96．88分。适宜贵州省春季用种．     

卤虫去壳卵在河蟹育苗中应用的研究

本文比较了卤虫去壳卵、无节幼体和人工合成饵料在河蟹育苗中■Ⅲ～■Ⅴ期的饵料效果,探讨了卤虫去壳卵替代无节幼体在河蟹育苗中应用的可能性。     

Relationship between nutritional and rearing parameters of Octopus maya juveniles fed with different rations of crab paste

To study the effect of feed ration on rearing and nutritional conditions of Octopus maya juveniles (7–10 days old), two groups of octopuses were fed on 10% and 30% rations, using a crab paste agglutinated with gelatine, when compared to another control group fed ad libitum on crab muscle tissue. The agglutinated diet was well accepted by the octopuses at this early stage. When considered together, the marginally higher survival of the 30% group and probably higher levels of the other rearing performance parameters (growth and feeding rate) indicate that this feed ration is more adequate than a 10% feed ration for rearing O. maya under these conditions. Octopuses fed 30% also generally showed higher total energy per gram of arm tissue and oxygen consumption, as well as different proteolytic activity. In addition, the mentioned nutritional differences influenced by the feed ration were found to be statistically correlated to the promoted growth and the end survival and feeding rates.     

斑鳜的人工繁殖与苗种培育试验

2005-2006年,进行了斑鳜的人工繁殖和苗种培育试验.试验结果表明,催产斑鳜亲鱼18组,雌鱼平均体质量380 g.催产率83%;获受精卵10.85万粒,受精率75%;获水花6.62万尾,孵化率61%.水花于水泥池中养至平均全长2.0cm 苗种成活率72%;平均全长2.0 cm苗种养至平均全长5.0 cm苗种成活率88.5%,1334 m<'2>池塘放养平均全长2.0锄苗种6200尾,经93 d养殖,收获鱼种4371尾,平均全长12.66 cm.平均体质量32.39 g,养殖成活率70.5%.     

笼养高邮鸭常规蛋品质测定与分析

本试验中选取了230日龄笼养高邮鸭所产鸭蛋50只,测定其蛋重、蛋形指数、蛋壳强度、哈氏单位、鸭蛋比重、蛋壳厚度和蛋黄颜色等,其值分别为76．5g,1．36,5．0kg／cm^2,73．8,1．091g／cm^3,0．43mm,8．60,显示其具有较好的品质。结果显示：从蛋品质方面考虑,蛋鸭笼养是可行的。     

养殖密度对克氏原螯虾幼虾生长、摄食和饵料利用影响

以体重(0.015±0.004)g克氏原螯虾(Procambarus clarkii)幼虾为研究对象,研究了50、100、300、600、900尾/m25种养殖密度对克氏原螯虾幼虾生长、摄食和饲料利用的影响,实验周期为30 d。结果显示:克氏原螯虾幼虾的体长、特定生长率、平均日增重、存活率和蜕壳率都随养殖密度的增大而减小,其中日增重由(0.007±0.002)g下降为(0.002±0.001)g,蜕壳率由(100±0.000)%下降为(37.222±3.928)%,降幅明显;体长、体重变动系数随养殖密度的增大而增大。每组个体的平均摄食量和摄食率均与养殖密度成反比。此结果表明养殖密度的增大总体来说不利于克氏原螯虾幼虾的生长和摄食。在饲料利用方面,饵料转化率在各养殖密度组之间无明显差异;蛋白质特定生长率、脂肪特定生长率和脂肪储积率随养殖密度增大呈减小趋势,蛋白质储积率呈增大趋势。