水草和螺蛳对克氏原螯虾性腺发育的影响

本文对水草、螺蛳、水草+螺蛳三种投喂方式对克氏原螯虾性腺发育的影响进行了研究。结果显示,水草+螺蛳组的克氏原螯虾(雌虾体长9.5cm)的抱卵量826粒/尾,显著高于水草组、螺蛳组(P<0.05),成熟度5.95%、抱卵指数19.20粒/g、亲虾成活率89.66%、抱卵率79.31%,结果均高于投喂水草组或螺蛳组。显然,植物性和动物性饵料混合喂养更有利于促进克氏原螯虾雌虾性腺发育及提高亲虾的成活率。     

克氏原螯虾仿生态繁殖池布草技术研究

为研究克氏原螯虾仿生态繁殖池的布草技术,采用栽植品种相同、面积不同的水草和品种不同、面积相同的水草两种方式进行仿生态繁殖试验。结果表明,土池中栽植不同面积的水草与亲虾的成熟度、抱卵量、抱卵率和存活率间均呈极显著相关(R>R0.01);当亲虾的放养量为150 kg/667 m2,水草栽植面积占池塘面积的40%时,亲虾的成熟度、抱卵量、抱卵率和存活率均达到最大值。混合栽植水草与栽植单一种类的水草之间,克氏原螯虾亲虾的成熟度差异极显著(P<0.01),抱卵量、抱卵率、存活率均差异显著(P<0.05)。混合栽植水草优于栽植单一种类的水草。     

栖息环境对克氏原螯虾抱卵量的影响

6口池各放克氏原螯虾100尾,分别给予不同的栖息环境,对人工创造生态环境对克氏原螯虾抱卵量的影响进行了对比研究.结果认为池塘具备良好的土质洞穴环境可明显地提高克氏原螯虾的繁殖力.     

亲虾规格、隐蔽物、光照度及密度对克氏原螯虾繁殖效果的影响

按照正交试验设计原理,不考虑交互作用,选择L9(3～4)正交表,研究了亲虾规格、隐蔽物、光照度及放养密度4个因素对克氏原螯虾亲虾成活率、抱卵率、产卵量的影响,试验历时57d。研究结果表明,不同亲虾规格对抱卵量影响显著(P0.05),且规格为35～50g亲虾的平均抱卵量为489.8粒/尾,分别较25～30g、30～35g高20.8%、11.6%;不同隐蔽物种类对亲虾的成活率影响显著(P0.05),使用"水草+石棉瓦+砖块"作为隐蔽物,亲虾平均成活率为95.69%,分别较"水草+石棉瓦+PVC管"、"三角形栖息物"高9.6%、3.5%;光照度为50～500lx,亲虾的平均抱卵量为467.17粒/尾,高于其他两个光照度水平;放养密度为20尾/m2,亲虾的平均抱卵率为64.98%,高于其他两个密度水平。因此,亲虾规格为35～50g、隐蔽物种类为‘水草+石棉瓦+砖块’、光照度为50～500lx、放养密度为20尾/m2"组合有利于提高克氏原螯虾的繁殖效果。     

克氏原螯虾苗种规模化繁育技术

为解决克氏原螯虾苗种规模化供应短缺问题,以洪泽湖地区克氏原螯虾为研究对象,在研究、掌握本地区克氏原螯虾繁殖习性的基础上,设计并建设了由700 m2大棚产卵池和50 m2加温孵化温室及若干特制网箱组成的苗种规模化繁育设施.2007年9月分批次将16 443只成熟的克氏原螯虾亲虾放入大棚产卵池特制网箱,通过降低光照、微孔增氧、循环流水等措施,先后获得抱卵虾6 053只,平均抱卵率为45.7%;抱卵虾移入温室后,在控温、流水条件下孵化,获得了平均体长0.88 cm的稚虾76.9万尾,平均孵化率为81.1%.     

克氏原螯虾的食性、繁殖和栖息习性研究

2005年2月～2006年4月对长江中下游地区的湖南、湖北、江西、安徽、江苏和上海6省市克氏原螯虾的资源进行了调查和研究.结果表明,该虾昼伏夜出,白天隐藏在洞穴或水草丛中,晚上活动和觅食;尤其喜欢栖息在壤土与砂质土壤、水草较集中茂盛处、静水和缓流水体中,繁殖季节爱掘洞.年产卵1次,体长70～107mm的雌虾抱卵100～320粒.天然水域克氏原螯虾主要以马来眼子菜、金鱼藻、轮叶黑藻、高等植物碎片、菹草为食,不同生长阶段和不同地理区域,其主要食物存在一定差异.     

克氏原螯虾人工诱导工厂化繁育关键技术研究

为了优化克氏原螯虾人工诱导工厂化繁育的关键技术,利用玻璃缸和塑料温棚水泥池开展了克氏原螯虾人工诱导繁殖、抱卵虾孵化及幼苗对冬季低温条件耐受能力的研究。采用提前放养亲虾、强化培育、搭建三角形四隔层垒起隐蔽物、孵化网袋、培育丰年虫开口饵料及适时出苗等技术措施,进行了195 d的试验。试验结果,克氏原螯虾亲虾的培育成活率达73.59 %,抱卵率达76.11 %,平均每平方米育成体长1~2 cm的幼苗2 300尾,孵化后亲虾的成活率达93.7 %;克氏原螯虾雌雄亲本选自不同水域,对亲虾培育成活率的影响不显著(P＞0.05),但长江水系和淮河水系杂交组亲虾的抱卵率显著高于自交组(P＜0.05);体长1~2 cm和2~3 cm的克氏原螯虾幼苗拥有较强的耐低温能力,可以在室外水泥池、池塘等生境中安全越冬。     

克氏原螯虾抱卵与非抱卵孵化比较研究

在实验条件下观察了克氏原螯虾克氏原螯虾抱卵与非抱卵孵化过程。详细描述了两者卵色变化情况，并对抱卵原因进行了初步探讨。     

维生素C、E及高度不饱和脂肪酸交互作用对克氏原螯虾繁殖性能的影响

在室内,将体质量20~40g的克氏原螯虾饲养在50cm×40cm×40cm的水族箱中,投喂7种饲料:基础饲料(对照组,试验饲料1);基础饲料+0.5%维生素C+0.02%维生素E+8%高度不饱和脂肪酸(含6%秘鲁鱼油和2%大豆卵磷脂)(试验饲料2);基础饲料+0.5%维生素C+0.02%维生素E(试验饲料3);基础饲料+8%高度不饱和脂肪酸(试验饲料4);基础饲料+0.02%维生素E(试验饲料5);基础饲料+0.5%维生素C(试验饲料6);2#青虾全价颗粒饲料(粗蛋白≥30%)(试验饲料7),每组饲料设置3个重复,研究了在饲料中添加维生素C、E及高度不饱和脂肪酸对克氏原螯虾培育成活率、抱卵率、抱卵量及孵化率的影响。76d的繁育结果表明,7组试验饲料对克氏原螯虾亲虾的培育成活率影响不显著(P0.05)。试验饲料2组亲虾的抱卵率(75%)和孵化率(82.8%)最高,显著高于对照组(P0.05)。饲料2组、3组、5组、6组亲虾的相对抱卵量差异不明显(P0.05),显著高于饲料4组(仅添加高度不饱和脂肪酸)、1组(P0.05),添加维生素C、维生素E的饲料3组的亲虾相对抱卵量最高,亲虾平均抱卵18粒/g,仅添加高度不饱和脂肪酸的饲料4组,亲虾培育成活率及相对抱卵量较低。结果表明,维生素C、维生素E和高度不饱和脂肪酸具有交互作用,能提高克氏原螯虾的繁殖性能。     

克氏原螯虾工厂化繁育技术研究

为了探索克氏原螯虾工厂化育苗技术,2008年利用室内水泥池中进行了克氏原螯虾的人工繁育试验,取得了初步的成功,亲虾培育成活率84.3%;交配抱卵率81.6%;受精卵经孵化出苗率71.9%;平均每立方水体出苗数5593尾;平均每只亲虾出苗125尾;每只抱卵虾出苗182尾.     

Sex reversal in Nile tilapia (Oreochromis niloticus Linnaeus) by androgen immersion

Two experiments were conducted to investigate the efficacy of three androgens applied through immersion treatments on the sex ratio of Nile tilapia (Oreochromis niloticus L.) fry. In experiment 1, 14 days post‐hatching (DPH) larvae were exposed to a single immersion treatment in 17α‐methyltestosterone (MT), 17α‐methyldihydrotestosterone (MDHT) or 17α‐ethynyltestosterone (ET) at 200, 600 and 1800 μg L^?1 over 4 h (130 larvae per treatment). In experiment 2, Nile tilapia larvae were exposed to the higher androgen concentration (1800 μg L^?1) applied as either a single immersion (14 DPH) or double immersion (10 and 14 DPH) over 4 h (125 larvae per treatment). Change in sex proportion within each experiment as well as between experiments was analysed by the chi‐square test. In experiment 1, MT, MDHT and ET were equally effective in significantly increasing the proportion of males when applied at 1800 μg L^?1 (86.0%, 90.0% and 86.7% respectively). At 200 μg L^?1 none of the androgens altered sex ratio. At 600 μg L^?1, only MDHT slightly, but significantly skewed the sex ratio towards males (73.0%). In experiment 2, a single immersion treatment at 14 DPH (1800 μg L^?1) significantly increased the proportion of males, but at this time the response was significantly hormone dependent (MDHT, 100.0%; MT, 91.6%; ET, 76.9%). When compared with a single immersion, two‐immersion treatments significantly increased the proportion of males in the MT‐treated group (from 91.6% to 98.3%), decreased the proportion of males in the MDHT group (from 100.0% to 93.4%) and had no significant effect the ET‐treated group (change from 76.9% to 82.5%). The overall comparison of the sex ratio among same treatments from different experiments (a single immersion in 1800 μg L^?1) was not significantly different.     

克氏原螯虾的适宜蛋氨酸需求量

文章通过观察人工养殖环境下,克氏原螯虾 (Procambarus clarkiaii) 在堆积的竹筒和PVC管2种类型洞穴中的分布情况,分析比较了克氏原螯虾对2种洞穴的选择适应性和空间分布占比规律,不同洞穴内外的雌雄比例分布规律,及单一洞穴内虾的数量分布及雌雄比例规律。实验结果表明,克氏原螯虾喜栖息躲藏于洞穴中 (A组83.47%,B组89.87%),尤其喜栖息躲藏于竹筒洞穴中[B组竹筒 (71.80%)和PVC管 (11.63%)]。垂直摆放洞穴的上下位置会影响克氏原螯虾分布,克氏原螯虾更喜欢在中下层和下层洞穴中躲藏,其分布数量由下而上依次降低。克氏原螯虾具有一雄多雌同居一穴的现象,不同垂直空间雌雄分布比例没有明显规律,但雌雄比最高分别出现在A组的最下层 (3.43∶1) 和B组竹筒洞穴的最上层 (2.86∶1)。

     

Induced triploidy in the European clam, Ruditapes decussates (L.), and performance of triploid larvae

Abstract. For the first time, effective treatments using cytochalasin B were developed to induce triploidy in the European clam, Ruditapes decussatus (L.). The percentage of triploid embryos was assessed by karyological or image analysis. Two treatments (0·5 or 1 mg of cytochatasin B (CB) per ml of dimethyisulfoxide in 1 litre of sea water) were applied at different times after fertilization (10 to 25min), for two different periods (15 and 20min). Best results were obtained for a CB concentration of 1 mg/1. When treatment was applied 15min after fertilization for a 20min period, 94% and 95% of triploid embyros were obtained in two repeated experiments. At metamorphosis, the treated larvae appeared to be no smaller than the control larvae in all experiments. However, in general, significantly higher mortalities for CB-treated batches were found when compared with the untreated batch.     

哈氏弧菌外膜蛋白与溶藻弧菌脂多糖偶联疫苗的效果研究

采用十二烷基肌氨酸钠法提取哈氏弧菌(Vibrio harveyi)SpGY020601株的外膜蛋白(OMPC),采用酚水法提取溶藻弧菌(Vibrio alginolyticus)EpGS021001株的脂多糖(LPS).通过碳化二亚铵(EDC)介导的缩合反应,将哈氏弧菌的OMPC与溶藻弧菌的LPS偶联.OMPC-LPS偶联物、未偶联的哈氏弧菌OMPC、溶藻弧菌LPS、哈氏弧菌OMPC和溶藻弧菌LPS的简单混合物以及生理盐水按相同程序免疫卵形鲳鲹(Trachinotus cvatus).检测血清溶菌酶活性、血清抗体微量凝集反应结果显示,卵型鲳鲹经OMPC-LPS偶联物、OMPC、LPS以及二者的简单混合物免疫后,各免疫组间血清溶菌酶活性没有显著差异(P＞0.05),但均显著高于生理盐水对照组(P＜0.05);OMPC-LPS偶联物免疫组的血清抗溶藻弧菌EpGS021001抗体效价较单纯溶藻弧菌LPS免疫组、简单混合物免疫组出现得早,抗体滴度高;与此类似,OMPC-LPS偶联组中抗哈氏弧菌SpGY020601的血清抗体效价较单纯哈氏弧菌OMPC组、简单混合组出现得早,抗体滴度高,且持续时间长;对EpGS021001、SpGY020601的攻击,OMPC-LPS偶联物免疫组的保护率分别为85%和95%,高于单纯溶藻弧菌LPS免疫组的70%、单纯哈氏弧菌OMPC免疫组的75%,也高于简单混合物免疫组的80%和82.5%.     

3种微生物制剂调控工厂化对虾养殖水质的研究

研究了地衣芽孢杆菌(Bacillus licheniformis,BL)、荚膜红假单胞菌(Rhodopseudomonas capsulate,RC)和乳酸杆菌(Lactobacillusspp.,LB)对凡纳滨对虾(Litopenaeus vannamei)工厂化养殖水质的影响。结果表明,施用不同微生物制剂组合,其作用效果各不相同。各组微生物制剂均能降低水体中氨氮,地衣芽孢杆菌 荚膜红假单胞菌(G1)组、地衣芽孢杆菌 荚膜红假单胞菌(G2)和地衣芽孢杆菌 乳酸杆菌(G3)组NH4 的相对降解率为62%、63%和65%;前21d,G2组降低NH4 效果最明显,相对降解率为79%。在降低NO2-方面,G1组的效果较好,相对降解率为46%;但各处理组对于PO34-、COD均无显著效果。相对而言,G1组改善养殖水质的效果最好。实验中微生物制剂的不同施用频率对水质的净化没有明显的差别。各项水质指标均随养殖时间的推移呈现不断上升的趋势。     

Virulence of a chimeric recombinant infectious haematopoietic necrosis virus expressing the spring viraemia of carp virus glycoprotein in salmonid and cyprinid fish

Infectious haematopoietic necrosis virus (IHNV) and spring viraemia of carp virus (SVCV) are both rhabdoviruses of fish, listed as notifiable disease agents by the World Organization for Animal Health. Recombinant rhabdoviruses with heterologous gene substitutions have been engineered to study genetic determinants and assess the potential of these recombinant viruses for vaccine development. A recombinant IHNV (rIHNV), containing the full‐length genome of a European IHNV strain, was modified by deleting the glycoprotein (G) gene and replacing it with a European SVCV G‐gene to make the rIHNV‐Gsvcv. The chimeric rIHNV‐Gsvcv level of virulence in rainbow trout, common carp and koi was assessed, and its ability to induce a protective immune response in surviving koi against wild‐type SVCV infection was tested. The rIHNV‐Gsvcv infection of trout led to high mortality, ranging from 78% to 92.5%, after immersion. In contrast, no deaths occurred in juvenile common carp after infection with rIHNV‐Gsvcv by either immersion or intraperitoneal (IP) injection. Similarly, koi infected with rIHNV‐Gsvcv via IP injection had little to no mortality (≤9%). Koi that survived initial infection with a high dose of recombinant virus rIHNV‐Gsvcv were protected against a virulent SVCV challenge resulting in a high relative per cent survival of 82.5%.     

大鲵人工繁殖技术初步研究

利用长200m、宽5．2m、高4．5m的山洞,在6m^2和0．48m^2的养殖池中用石板材和鹅卵石搭设人工洞穴,以人工养殖的Ⅴ-Ⅶ龄的子二代大鲵作为亲体开展人工繁殖研究。亲鲵培育水温19．0～20．5℃,pH7．2—7．3,DO5．8～7．4mg／L,光照〈300Lux;催产选择在7月上旬进行。激素选用LRH-A2＋HCG,剂量LRH—A2 10-20ug／kg＋HCG1000～2000IU／kg,雌雄同剂量。一次性腹腔注射;受精卵孵化温度18～18．5℃,pH7．2～7．3,DO6．0—8．0mg／L,光照〈100Lux。2010年7月催产雌鲵26尾,雄鲵24尾,催产后第4d,4尾雌鲵产卵3800粒,获受精卵962粒,受精率25．32％。受精卵经35—38d的孵化,共孵出稚鲵172尾,孵化率为17．88％。     

Soy protein concentrate as a substitute for fish meal in diets for juvenile Acanthopagrus schlegelii: effects on growth,phosphorus discharge and digestive enzyme activity

The current high demand and cost of fish meal (FM) necessities the evaluation of alternative plant protein ingredients in diets of farmed marine fish. A 56‐day feeding trial was performed to study the effects of replacement of FM with soy protein concentrate (SPC) in diets of Acanthopagrus schlegelii. Diets were prepared at levels of 0%, 30%, 47.5%, 65%, 82.5% and 100% SPC, respectively, replacing FM. The results indicated no significant differences (p > .05) in % weight gain (WG) and specific growth rate of fish fed S30% to S82.5% diets compared with the control diet while, further inclusion at 100% significantly depressed growth performance. SPC inclusion and phytase supplementation significantly affected the phosphorous discharge (P‐load) showing lowest value (3.83 ± 0.53 g/kg WG) in S100% compared to control (14.79 ± 0.37 g/kg WG) and in fish fed S30% diet (13.24 ± 0.89 g/kg WG) (p < .05). The results of this study showed that FM could be substituted up to 82.5% by SPC in the diet of Acanthopagrus schlegelii fingerlings (5.53 ± 0.12 g) without any adverse effects. Phytase supplementation SPC based diets could be effective in reducing the phosphorus load in the aquatic culture environment.     

紫海胆人工育苗技术的研究

为比较紫海胆不同家系间幼体生长发育的差异,实验构建了9个紫海胆全同胞家系,比较了其受精率、孵化率、幼体存活率、变态率、开口率、幼胆生长、性腺发育和消化道微生物组成。方差分析表明,各个家系的受精率均在95%以上,无显著性差异,而其他指标在不同家系间均存在显著性差异。孵化率、早期幼体存活率、晚期幼体存活率、变态率和开口率最高的家系分别为3号 (58%)、1号 (83%)、4号 (90%)、2号 (75%)和9号 (100%),最低的家系分别为6号 (0%)、3号 (42%)、2号(76%)、9号 (6%)和5号 (24.5%)。幼胆生长速率最快是3号家系为146%;最慢的是5号家系为76%。3号家系在实验结束时性腺发育明显;而其他家系性腺未见发育。3号家系的消化道微生物中拟杆菌门丰度较高,变形菌门丰度低;生长速率较慢的5号家系则与之相反。研究结果表明,紫海胆不同家系间的生产性状存在差异,具有选育改良的潜力,实验为紫海胆良种培育积累了相关数据。

     

Effect of dietary inulin and oligosaccharides as prebiotics for weaning turbot, Psetta maxima (Linnaeus, C. 1758)

Preliminary experiments were undertaken to investigate the effect of dietary inulin (Raftiline ST), oligofructose (Raftilose P95) and lactosucrose on the growth and intestinal bacteria of the marine carnivorous turbot, Psetta maxima. Turbot larvae were weaned on compound diets containing 2% Rafiline ST, 2% Raftilose P95 or 2% lactosucrose; 2% cellulose was the carbon source in the control group. The final mean weight of the group weaned with Raftilose P95 was significantly higher than those observed with the other diets. The bacterial load was highly variable in weaning turbot, especially with respect to the putative Vibrio spp. growing on TCBS agar which, in general, seemed to be dominant. Of the total load of bacterial isolates from turbot weaned on oligofructose, 14% consisted of a strain of Bacillus spp. This strain could use Raftilose P95 as a single source of carbon, and it might play a role in the beneficial effect of oligofructose on turbot growth, since Bacillus spp. have been documented as probiotics in fish.