Effects of Harvest Period on the Production of White River Crayfish,Procambarus acutus acutus

Abstract

Crayfish harvest was initiated at a cool water temperature (15°C) and warm water temperature (20°C) from culture ponds (0.1 ha) with a resident population of white river crayfish, Procambarus acutus acutus.Crayfish were harvested for 24 days for a total of 1,977 trap-days/ha (March 9-May 12, 2000 from the cool-harvest treatment and May 5-June 15, 2000 from the warm-harvest treatment). The mean total length (TL) and production of harvested white river crayfish (WRC) was similar between treatments. The population structures of WRC from the cool and warm periods of harvest were substantially different; large WRC (≤100 mm TL) from the cool-harvest period were 3.1 times more abundant than large WRC during the warm-harvest period. A similar number of small WRC were harvested from the two treatments; however, those small WRC harvested during the warm period was significantly longer than the small WRC during the cool-harvest period. The estimated large WRC biomass contribution to the total harvest from the cool-harvest period was 37% in comparison to 15% during the warm-harvest period. The estimated dollar value of the production during the cool-harvest period was 40% more than that from the warm-harvest period.     

不同地区克氏原螯虾群体的形态差异分析

运用3种多元统计方法,对江苏、安徽、山东和湖北4个不同地区克氏原螯虾（Procambarus clarkii）野生群体的13个形态比例参数进行比较研究。聚类分析结果显示,山东和江苏2个克氏原螯虾群体之间的形态最为接近,而与湖北和安徽群体间趋异程度逐渐增大。主成分分析中,雌性群体贡献率分别是主成分1为46.104%、主成...     

亚硝酸盐和硫化物对克氏原螯虾幼虾的毒性效应研究

采用静水法生物测试,研究了亚硝酸盐(NO2--N)和硫化物(S2-)对克氏原螯虾(Procambarus clarkii)幼虾急性毒性效应。实验结果表明,克氏原螯虾幼虾的死亡率随着NO2--N和S2-浓度的升高和暴露时间的延长而显著上升。NO2--N对克氏原螯虾幼虾24、48、72、96h的半致死浓度(LC50)分别为108.09、90.08、73.02、69.74mg/L。S2-对克氏原螯虾幼虾24、48、72、96h的半致死浓度(LC50)分别为12.96、9.57、7.62、4.63mg/L。克氏原螯虾幼虾对NO2--N和S2-的安全浓度(SC)分别为6.97mg/L和0.46mg/L,为相应渔业水质标准的35倍和2.3倍,说明克氏原螯虾对NO2--N和S2-的毒性具有一定的耐受力,且对NO2--N的耐受能力强于S2-。     

稻虾综合种养水稻品种筛选研究进展

稻虾（克氏原螯虾）综合种养是推进水稻绿色生产的重要方式,促进了水稻产业的提质增效,有利于水稻产业转型升级。近年来,稻虾综合种养在全国多地迅速推广,但当前稻虾还存在种养产量和效益不稳、稻虾种养技术亟待优化、尤其是优质高产抗倒水稻品种较为缺乏的问题。已有研究者针对稻虾连作或共生种养条件下的水稻品种选用开展了各有侧重的研究。本文阐述了目前稻虾种养下水稻品种筛选的研究进展,探讨了不同稻虾种养模式对水稻品种特性的要求,提出了今后稻虾种养品种选育和筛选应用的发展方向,可为提高稻虾综合种养质量和效益提供参考。     

Dietary calcium requirement of red swamp crayfish (Procambarus clarkia)

To investigate dietary calcium requirement of red swamp crayfish (Procambarus clarkia), six semi‐purified diets were formulated to contain different concentrations of calcium (2.7(control group), 6.1, 11.9, 17.6, 23.5 and 29.1 g/kg calcium). Each diet was hand‐fed to triplicate of 15 crayfish with average initial body weight (6.22 ± 0.87) g for 8 weeks. The results showed that weight gain rate (WGR) significantly increased and feed conversion ratio (FCR) significantly decreased from 11.9 to 23.5 g/kg groups (p < .05). Protease activities in intestine and hepatopancreas and parathyroid hormone concentrations in serum significantly decreased with increasing dietary calcium levels (p < .05), while calcium and phosphorus contents in exoskeleton, calcium content in muscle and calcitonin concentrations in serum significantly increased (p < .05). The activities of lipase and amylase in intestine and hepatopancreas, serum alkaline phosphatase and total vitamin D concentrations in serum had significant increase as dietary calcium content increased up to 11.9–17.6 g/kg (p < .05). The inorganic phosphorus content in 29.1 g/kg group was significantly lower than those in other groups (p < .05). Broken‐line model analysis based on WGR and quadratic curve model analysis based on FCR showed that optimal dietary calcium requirement of red swamp crayfish ranged from 12.7 to 17.1 g/kg.     

克氏原螯虾黑鳃上一种木贼镰刀菌的分离鉴定

在患黑鳃病的克氏原螯虾鳃上分离到1株菌落呈淡米黄色的真菌菌株,经纯化培养、形态学观察和DNA测序,确定该菌株为木贼镰刀菌(Fusarium equiseti)。文章对木贼镰刀菌进行了种的形态描述、图片及与近似种区别的讨论。该真菌在克氏原螯虾上属于首次报道。研究菌种现保存于江苏农林职业技术学院生物工程技术中心真菌研究室,菌株编号为NLHf-3。     

不同地区克氏原螯虾遗传多样性的AFLP分析

利用AFLP分子标记技术对中国随州、济南、宁波和常熟4个地区克氏原螯虾(Procambarus clarkii)野生群体的遗传多样性进行了研究。结果表明,5对选择性引物在4个群体120个个体中,共扩增出276个位点,多态位点241个;4个群体的杂合度分别为0.200 9、0.200 9、0.228 2、0.143 7,Shannon’s指数分别为0.292 9、0.292 9、0.339 9、0.213 9,可见4个克氏原螯虾群体均具有丰富的遗传多样性。分子变异分析结果显示,39.76%的遗传变异由群体间贡献,60.24%的变异分布于群体内个体之间,遗传分化指数FST=0.397 65(P<0.01),说明4个群体存在较明显的遗传分化。利用MEGA3.0软件构建的UPGMA系统进化树显示随州、济南群体差异小,可聚为一类,宁波、常熟群体各为一类。     

蛋白质、维生素E和Se对克氏原螯虾性腺发育的影响

[目的]分析饲料中添加蛋白质、维生素E和Se对克氏原螯虾繁殖发育的影响。[方法]通过L9(34)正交试验,研究蛋白质、维生素E和Se对克氏原螯虾雌虾性腺发育、抱卵量、抱卵指数和抱卵率的影响。[结果]在最优组合中,VE为主要因素,其次为蛋白质和Se;最优水平为0.05%VE、28.9%蛋白质和1 mg/kg Se。[结论]VE和Se的组合对克氏原螯虾性腺发育、抱卵量的增加、抱卵指数的增大和抱卵率的提高等具有补偿与协同作用。     

Reproduction efficiency of the crayfish Procambarus acanthophorus in relation to size and diet

Reproductive efficiency of the largest individuals and a random group of broodstock of crayfish Procambarus acanthophorus was measured using two commercial shrimp feeds, Feed 1 (F1) broodstocks (40%/9% protein/lipids) and Feed 2 (F2) growth-out (35%/7% protein/lipids). An experimental design of four treatments with two replicates was used. Females were labeled with elastomers to determine the time between spawning and number of offspring per treatment. The number of ovigerous females in the largest individuals fed F2 (58) was significantly higher than ovigerous females in the control group fed F1 (30).The number of young crayfish per female produced in the largest individuals (173 ± 71.6) treatment was significantly higher than the crayfish produced in the control group (86.6 ± 42.6). The average interval between spawns, regardless of diet, in the largest females was 2.9 months and 2.6 months in control group females.     

克氏原螯虾染色体及其核型

染色体是遗传物质的载体,是研究细胞遗传学的基础,为研究克氏原螯虾染色体及其核型,实验以性未成熟雄性个体的精巢为材料,采用低渗和空气干燥常规方法制备细胞分裂中期染色体标本,研究了克氏原螯虾染色体及核型。Giemsa和DAPI染色后在显微镜下观察到清晰的精母细胞减数分裂中期二价体和精原细胞有丝分裂中期染色体时相。对减数分裂中期二价体及有丝分裂中期染色体进行了数目上的统计。结果显示,克氏原螯虾二倍与单倍染色体数目分别为2N=188和N=94。由于有丝分裂染色体形状微小,核型分析困难,故选取减数分裂中期二价体,根据长度及着丝点位置对其进行了初步核型分析,核型公式为N=55M+22(SM,ST)+17T,未发现异形性染色体。