Ammonia and pH effects on some metabolic parameters and gill histology of silver catfish, Rhamdia quelen (Heptapteridae)

The aim of the present study was to assess the effect of ammonia exposure at different pH on survivorship and metabolic parameters in the liver, muscle and gill histology of silver catfish (Rhamdia quelen). The 96 h-LC50 of un-ionized ammonia (mg L^− 1) at pH 6.0, 7.5 and 8.2 were: 0.44 (C.I. 0.38–0.49), 1.45 (C.I. 1.25–1.65) and 2.09 (C.I. 1.85–2.36), respectively. Survival of juveniles exposed to different ammonia levels was altered by pH, and fish exposed to all ammonia levels and different pH showed muscle glucose, muscle and liver glycogen reduction. Liver glucose and muscle and liver lactate levels increased in all fish exposed to ammonia as compared to the control. Exposure to waterborne ammonia increased total ammonia levels in both tissues and also induced gill epithelium damages such as lamellar fusion and edema as compared with controls at different pH. Silver catfish exposed to pH 6.0 and different NH₃ levels presented significantly higher hepatic glucose and protein levels when compared to those maintained at low NH₃ levels. Juveniles exposed to NH₃ levels at pH 7.5 and 8.2 showed lower hepatic protein levels compared to those maintained at low NH₃ levels. These parameters are indicative of pH dependence on ammonia toxicity in silver catfish. The metabolic parameters and gill histology may be used as early indicators of ammonia toxicity in silver catfish.     

Determination of mortality in exploited freshwater pearl mussel (Margaritifera margaritifera) populations

Estimates of mortality, based on relative numbers of live mussels and empty shells observed were obtained for a sample of seven exploited Scottish freshwater pearl mussel (Margaritifera margaritifera) populations. Total mortality (Z) estimates ranged from 0.058 to 0.189 year⁻¹ and fishing mortality (F) estimates ranged from 0.005 to 0.129 year⁻¹. General trends of increasing Z and F with age were apparent. Pearl fishers generally targeted larger, older mussels. In one heavily exploited population, the Z and F estimates converged, indicating that most of the mortality in older mussels (>50 years) was due to the effects of destructive pearl fishing. Since a complete ban on pearl fishing was introduced in 1998, illegal pearl fishing has continued albeit at a reduced level.     

插片后珍珠蚌生长性状及其无核珍珠成珠率和大小

为研究MAP2K1 (MEK1) 基因在三角帆蚌 (Hyriopsis cumingii) 性别决定中的作用,采用cDNA末端快速克隆技术 (Rapid-amplification of cDNA ends, RACE) 克隆了MAP2K1基因序列,利用实时荧光定量分析比较MAP2K1基因在三角帆蚌6个组织 (性腺、闭壳肌、肝胰腺、鳃、外套膜、斧足)、早期发育阶段 (1—8月龄) 性腺和1—3龄雌雄性腺中的表达水平,利用原位杂交确定MAP2K1基因在2龄三角帆蚌性腺中的定位。结果显示,MAP2K1基因开放阅读框 (ORF) 长度为1 194 bp,编码397个氨基酸。MAP2K1基因在卵巢中高表达;早期发育阶段在2月龄表达量最高;1—3龄的表达结果显示,MAP2K1基因在卵巢中的表达量均高于同期精巢中的表达量 (P<0.05)。原位杂交结果显示,MAP2K1基因在雌性三角帆蚌的卵母细胞及卵子上有明显的杂交信号。RNAi结果显示,干扰MAP2K1基因的上游基因C-MOS后,下游基因MAP2K1在雌性中的表达下降了82.31%,在雄性中的表达下降了73.60%。推测MAP2K1基因可能参与三角帆蚌的卵巢发育过程,在三角帆蚌中属于偏雌性基因,其表达受C-MOS基因的影响。     

混合暴露条件下菲律宾蛤仔不同组织对几种重金属的富集与释放特征

应用双箱动力学模型模拟了菲律宾蛤仔在Pb、Zn、Cu、Cd、Cr、Hg和As 7种重金属混合暴露条件下,内脏团、鳃、斧足及基部和外套膜组织对重金属的生物富集与释放实验,并通过非线性拟合得到菲律宾蛤仔各组织对7种重金属的富集速率常数k1、排出速率常数k2、生物富集系数BCF、生物半衰期B1/2、富集平衡时生物体内重金属含量CAmax等动力学参数。结果表明,1)重金属在菲律宾蛤仔不同组织器官中的富集具有选择性,理论平衡状态下,Cu、Cd、As、Pd在各组织的含量分布(CAmax):内脏团斧足及基部鳃外套膜;Cr分布规律(CAmax):内脏团鳃斧足及基部外套膜;Hg分布规律(CAmax):斧足及基部外套膜鳃内脏团;Zn分布规律(CAmax):斧足及基部鳃外套膜内脏团。2)菲律宾蛤仔对不同重金属的富集系数存在显著差异(P0.05),对Cu富集程度最高,其富集系数范围为1514.0-4818.0;其次是Cd和Hg,富集系数范围分别为104.5-975.4,255.9-447.4;As、Cr、Pb、Zn离子在菲律宾蛤仔体内富集程度较低,其富集系数均在300以内。3)菲律宾蛤仔对重金属的释放能力较差,双箱动力学模型可较好地反映混合暴露条件下菲律宾蛤仔对重金属的富集特征,但不适合对其释放特征进行描述。     

北部湾钦州港近江牡蛎重金属污染分析

为近江牡蛎的食用安全及养殖环境监督管理提供科学依据,2015年7—11月在北部湾钦州港采集近江牡蛎样品,利用原子荧光光度计和原子吸收光谱仪测定近江牡蛎体内重金属含量,分析其污染程度。结果显示,调查海域牡蛎体内重金属平均含量从高到低依次为ZnCuCdCrAsPbHg,其中Zn、Cu含量较高,平均值分别为532.03、126.96 mg/kg。Cu参照《无公害食品水产品有毒有害物质限量》(NY 5073-2006),发现除了7月2号站样品未超标,其余样品均超标,超标率达89%。As参照《食品安全国家标准食品中污染物限量》(GB 2762-2012),发现总超标率为11%,仅7月3号站样品存在超标。Pb、Hg含量较低,其平均值分别为0.02、0.009 mg/kg。重金属富集系数揭示近江牡蛎对Zn、Cu、Cd、Cr富集严重。膳食暴露评估方法显示,重金属的膳食摄入量低于联合国粮食和农业组织的食品添加剂联合专家委员会(JECFA)推荐的暂定每周摄入量,钦州湾近江牡蛎属于安全食用范围。     

淮河橄榄蛏蚌繁殖类型与性腺发育观察

对淮河橄榄蛏蚌（Solenaia oleivora Heude）繁殖类型和性腺发育特征进行了系统的研究。结果表明,橄榄蛏蚌为短期孵育型,繁殖期从3月至6月初,3—5月为繁殖高峰期,发现的最小怀幼雌蚌为2⁺龄;雌蚌内外2对鳃丝均可作为育儿囊,属于外鳃类的四生型,一次怀幼数量在134.9万~402.1万只。以雌蚌怀幼为第一判断标准,并结合卵巢组织切片,确认中国橄榄蛏蚌为一个繁殖周期内多次排卵繁殖类型。雌雄生长未见显著差异。橄榄蛏蚌性腺发育可分为增殖期、生长期、成熟期、排放期及休止期5个时期,卵巢和精巢发育基本同步。组织切片和扫描电镜均显示,卵母细胞通过直径约5μm的卵柄与滤泡壁相连;早期卵母细胞（直径小于17 μm）表面无细胞膜,而后期卵母细胞（约40 μm）表面出现明显的卵黄膜。橄榄蛏蚌精子为鞭毛型,头颈部呈子弹头形,最宽约2 μm;受精卵表面存在明显的卵膜孔,直径约1 μm,表明精子不能通过卵膜孔全部进入卵母细胞而受精。本研究成果为实现橄榄蛏蚌的人工繁育及利用奠定了科学基础,并为其他珍稀濒危蚌类的繁育保护提供借鉴。     

Dietary potassium requirement of fingerling Indian major carp,Labeo rohita (Hamilton), based on growth parameters,gill Na+‐K+ ATPase activity,tissue mineralization and antioxidant activities

To quantify the dietary potassium requirement of fingerling Labeo rohita (6.2 ± 0.12 cm; 1.98 ± 0.06 g), seven purified experimental diets (350 g/kg crude protein and 16.72 kJ/g gross energy) with graded levels of potassium (0.32, 1.35, 2.41, 3.46, 6.48, 9.47 and 12.39 g/kg diet) were fed to triplicate groups of fishes at 08:00, 12:00 and 16:00 hr to apparent satiation for 8 weeks. Live weight gain (LWG; 671.46%), specific growth rate (3.65%/day), protein efficiency ratio (2.16), protein gain (PG; 2.41 g/fish) and feed conversion ratio (1.32) were found to be best in fish fed diet containing 3.46 g/kg potassium. Gill Na⁺‐K⁺ ATPase activity was also highest in fish fed diet with 3.46 g/kg potassium. Potassium content of whole‐body, vertebrae and scales increased significantly with the increase in dietary potassium level up to 6.48 g/kg. Significant changes were also noted in serum malondialdehyde content, superoxide dismutase, catalase, glutathione peroxidase and alkaline phosphatase activity. Based on the maximum live weight and protein gain observed in the present study, the inclusion of 3.55 g/kg potassium is recommended for developing potassium‐balanced commercial feeds for intensive culture of fingerling L. rohita.     

盐度对俄罗斯鲟幼鱼血清渗透压、离子含量及鳃丝 Na+/K+-ATP 酶活力的影响

研究了急性盐度胁迫对7月龄俄罗斯鲟(Acipenser gueldenstaedtii)幼鱼[体质量(86.1±18)g]鳃丝Na+/K+-ATP酶活力、血清渗透压和血清离子(Na+、K+、Cl-)的影响。结果表明:幼鱼从淡水直接转入盐度15、20、25水中,96h死亡率分别为72.22%、100%、100%,其他组(盐度0、5、10)无死亡。各盐度组96h血清渗透压、Na+、Cl-浓度随盐度升高而增加,且各盐度组显著高于对照组(P0.05),盐度15组最高,盐度5、10组间各指标不存在显著差异(P0.05)。盐度组血清K+离子在48h中较对照组均显著降低(P0.05),96h时有所回升但仍低于对照组,盐度15与盐度5、10相比血清K+离子有显著性差异(P0.05),盐度5、10之间无显著性差异(P0.05)。盐度组鳃丝Na+/K+-ATP酶活力呈先下降后上升变化,48h为最低,与对照组有显著性差异(P0.05),96h时盐度5、10组鳃丝Na+/K+-ATP酶活力与对照组及组间无显著差异(P0.05),盐度15与对照组及盐度5、10均有显著差异(P0.05)。96h幼鱼的等渗点为303.2mOsm·kg-1,相当于盐度10.06,而Na+及Cl-等离子点分别为146.1mmol·L-1和136.8mmol·L-1,分别相当于盐度9.02和8.95。与盐度15组相比,盐度10及其以下处理组各项检测指标变化幅度相对较小,在幼鱼渗透调节范围之内,盐度10中养殖15d后各项指标与淡水组差异较小,因此7月龄俄罗斯鲟幼鱼已具备在盐度10及以下的咸水中生活的能力,但不能耐受高于10的盐度。     

条石鲷鳃的组织发育及鳃上钠钾三磷酸腺苷酶活性的早期变化

为完善条石鲷的早期组织发育过程,探索条石鲷仔鱼早期高死亡率的内在发育机制,实验对鳃器官的早期发育进行观察,结果显示:条石鲷仔鱼在1日龄时出现鳃原基;2日龄,原始鳃弓形成;3日龄,鳃丝原基出现;6日龄,鳃丝两侧的扁平细胞向外突出而形成原始的鳃小叶,假鳃出现;7日龄,鳃小叶基部出现泌氯细胞;8日龄,泌氯细胞开始分泌蛋白样物质;14日龄,鳃的结构分化发育完善.钠钾三磷酸腺苷酶(Na+,K+-ATPase)的相对活性从胚胎分裂期不断增加,直至器官分化期.此后活性逐渐降低,并保持在一个较低的水平,直至9日龄活性才开始上升.而12日龄之后又不断下降,到14日龄降至最低值(0.246±0.126) U/g.此后急剧上升,到18日龄升至最高值(4.731±0.309) U/g.从20日龄起,Na+,K+-ATPase的相对活性保持稳定上升,直至本次实验结束.结果表明,Na+,K+-ATPase活性的变化与鳃组织,尤其是与泌氯细胞的发育密切相关,而且在其活性较低的阶段,条石鲷仔鱼的死亡率较高.     

草鱼的两种新型免疫球蛋白基因IgZ-2和IgM-IgZ

在草鱼中新发现的两种免疫球蛋白重链的cDNA和基因组序列,其中的一种IgZ命名为IgZ-2,以区别于已报道的IgZ,另一种只有两个恒定区,一个恒定区与IgM相似而另一个与IgZ相似,这一特征与已报道的鲤的IgM-IgZ相似,故同样称为IgM-IgZ。分泌型IgZ-2的cDNA序列包含1889bp,编码539个氨基酸,其3'编码区包含267bp,但缺乏5'非编码区及部分可变区序列。分泌型IgM-IgZ的cDNA全长为1316bp,编码361个氨基酸,其5'非编码区包含3bp,3'非编码区包含227bp。膜结合型IgM-IgZ由两个膜外显子与CH2中的一个剪切位点剪切而成。氨基酸序列比对结果显示IgZ-2和IgM-IgZ的恒定区存在保守的半胱氨酸。系统进化树分析显示,草鱼IgZ-2以较高的支持率与斑马鱼IgZ聚为一枝,再与草鱼IgZ、草鱼IgM-IgZ和鲤IgM-IgZ这一枝聚为一类。用半定量RT-PCR检测IgZ-2和IgM-IgZ在4条草鱼的器官/组织中的表达,发现分泌型IgZ-2、分泌型IgM-IgZ和膜结合型IgM-IgZ在4条鱼中的表达存在个体差异,但主要都在免疫器官中表达。     

鲢鳙混养对三角帆蚌生长和养殖水质影响的围隔实验

2008年4月23日—9月21日通过围隔实验,研究了不同鲢鳙混养比例对三角帆蚌生长及水化学指标的影响。实验中鲢鳙混养比例设置了6个水平,分别为0/0(对照组),100/0,70/30,50/50,30/70和0/100。实验开始和结束时测量三角帆蚌湿重,壳长和壳宽。每个月上下旬测量围隔水化学指标包括NO3N、NO2N、NH3N、TN、TP、PO4P和COD。实验结果表明,鲢鳙混养比例100/0的围隔蚌壳长相对生长率显著低于混养比例0/0,50/50和0/100的围隔(P<0.05),而不同混养比例下蚌的成活率、蚌壳宽及蚌重增长均无显著差异(P>0.05)。从水质来看,混养比例30/70围隔TP显著低于100/0(P<0.05),COD显著低于100/0及70/30(P<0.05),NH3N显著低于100/0(P<0.05)以及PO4P显著低于70/30(P<0.05)。因此,综合蚌生长及水质指标,混养比例30/70围隔对三角帆蚌养殖最有利。     

The present situation of freshwater crayfish, Astacus leptodactylus (Eschscholtz, 1823) in Turkey

The only native crayfish species in Turkey, Astacus leptodactylus, is widely distributed in lakes and ponds in many parts of the country. Its distribution area was considerably expanded in Turkey after 1985 because of its commercial importance and declined catches from traditional good fisheries. Although consumption of A. leptodactylus has always been very low in Turkey, it was exported to western Europe until 1986. Due to over-fishing, pollution and a disease (crayfish plague), the total production decreased dramatically to 200 from 5000 tonnes annually. In recent years (1991–1998), there has been a gradual increase in the production of crayfish in Turkey from 320 to 1500 tonnes, but plague is still present.     

半滑舌鳎Cs-UBE2D4基因的克隆、表达模式及启动子活性

泛素-蛋白酶体系统作为重要的蛋白质修饰途径,参与多个生物学过程,其中泛素结合酶E2作为关键酶可以决定泛素化对靶蛋白的影响。为了探究泛素结合酶E2在半滑舌鳎雌性性腺发育中的作用,本研究克隆了半滑舌鳎Cs-UBE2D4基因的开放阅读框ORF,检测了该基因在不同组织和不同发育阶段性腺中的表达模式;构建了其启动子报告基因载体(pGL3-Cs-UBE2D4)并进行了启动子活性分析。Cs-UBE2D4开放阅读框为360 bp,编码119个氨基酸,含有保守的泛素结合酶E2结构域。荧光定量PCR结果显示,Cs-UBE2D4在雌鱼的各组织中广泛表达,其中在卵巢和肝脏中表达量较高,而在雄鱼中几乎检测不到表达;在卵巢各发育阶段中,该基因的表达量从90日龄开始上调,6月龄达到峰值,之后开始下调,在1.5龄时表达量最低,在3龄时表达量有所回升,其中6月龄表达量为90日龄表达量的1.97倍。双荧光素酶活性检测结果显示,Cs-UBE2D4启动子具有较强的转录活性。本实验将为进一步开展Cs-UBE2D4基因对半滑舌鳎卵巢发育和性别调控相关机制的研究提供理论依据。     

The effects of different Ca2+ concentration fluctuation on the moulting,growth and energy budget of juvenile Litopenaeus vannamei (Boone)

A 40‐day experiment was conducted to investigate the effects of different Ca²⁺ concentration fluctuation on the moulting, growth and energy budget of juvenile Litopenaeus vannamei with an initial wet body weight of (1.20±0.01) g. The Ca²⁺ concentration of the control group C385 was 385 mg L^?1 throughout the experiment, while the Ca²⁺ concentration of the C591, C803, C1155 and C2380 groups periodically fluctuated from 385 to 591, 803, 1155 and 2380 mg L^?1 respectively. The moulting frequency (MF) of the shrimp in the Ca²⁺ concentration fluctuating groups was significantly higher than those in the control group (P<0.05). The specific growth rates (SGR_d) and feed intake of the shrimp in the C591 and C803 groups were significantly higher than those in other groups (P<0.05), but no significant differences in feed efficiency were found among all groups (P>0.05). The shrimp in C591 and C803 groups spent significantly less energy in respiration, while depositing significantly more energy for growth than those in other three groups (P<0.05). These results showed that proper Ca²⁺ concentration fluctuation could increase the MF and growth rate of the juvenile L. vannamei, and according to the regression formula made using SGR_d and range of Ca²⁺ concentration fluctuation, periodically enhanced Ca²⁺ concentration of 295 mg L^?1 in the seawater was suggested to be used in shrimp culture.     

许氏平鲉低氧耐受能力及血液学和鳃组织学变化

为探明许氏平鲉低氧耐受能力及低氧胁迫过程中其血液生理生化指标和鳃组织形态结构变化,本研究分析了许氏平鲉临界氧分压(Pcrit)和失去平衡点(LOE)时溶解氧含量,观察了低氧胁迫和恢复溶解氧过程中呼吸行为和呼吸频率的变化,分析了血液生理[红细胞数目(RBC),白细胞数目(WBC),血红蛋白(Hb),红细胞积压(HCT)]、生化[葡萄糖、皮质醇]指标以及鳃组织形态学和鳃组织气体交换率(PAGE)变化。结果显示,在温度18 ℃、盐度30,pH值7.85的条件下,许氏平鲉[(88.01±5.34) g] Pcrit和LOE溶解氧含量分别为(3.96±0.11)和(2.60±0.21) mg/L。随着水体中溶解氧含量下降,血浆皮质醇和葡萄糖分别在LOE和Pcrit达到最高。许氏平鲉血液RBC、Hb和HCT在LOE达到最高。低氧过程中,许氏平鲉呼吸频率和PAGE分别于Pcrit和LOE达到最高,且低氧导致许氏平鲉鳃小片长度(SLL)、间距(ID)、周长显著增加;鳃小片宽度(SLW)则随水中溶解氧含量下降而变窄,在LOE处达到最小值。许氏平鲉鳃小片末端膨大、基质肥大、增生比例在低氧过程中显著增加。恢复正常溶解氧24 h后,上述各项检测指标恢复正常,与对照组无显著差异。实验中对照组各项指标无显著变化。研究表明,许氏平鲉对水体低溶解氧变化反应敏感,低氧应激导致其血液生理生化相关指标和鳃小片形态发生显著改变,恢复正常溶解氧24 h后可以显著缓解低氧胁迫应激。相关结果为研究许氏平鲉低氧耐受生理调控机制和高效健康养殖提供了理论依据和技术支撑。     

Effects of Cu-exchanged montmorillonite on growth performance, microbial ecology and intestinal morphology of Nile tilapia (Oreochromis niloticus)

A total of 360 Nile tilapia at an average initial body weight of 3.9 g were randomly allocated to 4 treatments, each of which had three replicates of 30 fish/tank and used to investigate the effects of Cu²⁺-exchanged montmorillonite (Cu-MMT) on growth performance, microbial ecology of the skin, gill and intestine, and intestinal morphology. The dietary treatments were: 1) basal diet, 2) basal diet + 1.5 g/kg MMT, 3) basal diet + 30 mg/kg copper as CuSO₄ (equivalent to the copper in the Cu-MMT treatment group), or 4) basal diet + 1.5 g/kg Cu-MMT. The results showed that supplementation with Cu-MMT significantly improved growth performance as compared to control and fish fed with Cu-MMT had higher growth performance than those fed with MMT or CuSO₄. Supplementation with Cu-MMT reduced (P < 0.05) the total intestinal aerobic bacterial counts and affected the composition of intestinal microflora with a tendency of Aeromonas, Vibrio, Pseudomonas, Flavobacterium, Acinetobacter, Alcaligence, Enterobacteriaceae decreasing as compared with control. Measurements of villus and microvillus heights at different sites of the intestinal mucosa indicated that dietary addition of MMT or Cu-MMT improved intestinal mucosal morphology. However, the microbial ecology of the skin and gill was not affected by the addition of CuSO₄, MMT or Cu-MMT. Supplementation with CuSO₄ had no (P > 0.05) effect on the growth performance, microbial ecology and intestinal morphology. The results showed that Cu-MMT exhibited antibacterial activity in vivo and protected intestinal mucosa from invasion of pathogenic bacterium and toxins, resulting in a positive effect on the growth performance.     

急性氨氮胁迫对虎斑乌贼肝脏、鳃和脑组织结构的影响

为了探讨氨氮对虎斑乌贼器官组织结构的影响,以体质量为(13.80±0.65)g的幼虎斑乌贼为对象,研究了氨氮胁迫对其肝脏、鳃和脑组织结构的影响。根据96 h的LC50实验结果设计5个梯度(0、1、3、6和12 mg/L)进行96 h的氨氮胁迫后,利用光学显微镜和透射电子显微镜观察其肝脏、鳃和脑组织结构。结果显示,在相同浓度的氨氮胁迫下,虎斑乌贼不同组织器官之间损伤程度存在差异,其中肝脏损伤的程度最大,对氨氮胁迫表现最敏感,其次是鳃组织和脑组织,组织器官损伤程度与氨氮浓度呈现正相关。氨氮胁迫浓度越大或胁迫时间越长,肉眼观察发现肝脏颜色越鲜红,肿胀和易糜烂程度越明显,可通过肉眼观察肝脏颜色和肿胀程度初步判断机体氨中毒程度;氨氮胁迫后,对肝脏和鳃组织造成较为严重的损伤,可能是虎斑乌贼氨中毒致死的原因。当氨氮高于或等于6 mg/L时胁迫96 h后,通过显微观察发现肝小叶轮廓模糊不完整、排列不紧密和胞浆疏松透明,大量的细胞核溶解,细胞出现空泡化,肝血窦扩张;通过电镜观察发现细胞核皱缩变形、核仁消失、线粒体嵴紊乱、线粒体空泡化、线粒体外室肿胀,高尔基体数量减少;显微观察发现鳃组织的泌氯细胞和上皮细胞核溶解,细胞出现空泡化、排列紊乱,鳃丝肿胀淤血、轮廓模糊不完整,并出现坏死脱落和缺损;通过透射电镜观察,发现细胞核皱缩、核膜破损和细胞核裂解,线粒体出现了皱缩变形、空泡化和不完整破损现象;观察脑组织的神经团和视叶,未发现脑组织的细胞有显著损伤。     

盐度胁迫对三疣梭子蟹鳃Na+/K+-ATPase酶活的影响

通过钼蓝法测定三疣梭子蟹在3组实验盐度的胁迫过程中第2对和第6对鳃Na⁺/K⁺-ATPase酶活的变化,比较了3组实验盐度胁迫1 d时,鳃Na⁺/K⁺-ATPase的酶活大小。结果表明,在盐度胁迫初期,3组实验盐度下第2对和第6对鳃Na⁺/K⁺-ATPase的酶活下降;之后,各组实验盐度下第2对和第6对鳃Na⁺/K⁺-ATPase的酶活开始随胁迫时间增长而上升;最后,各组实验盐度下第2和第6对鳃Na⁺/K⁺-ATPase的酶活下降并趋于稳定。另外,胁迫1 d时,各组实验盐度下三疣梭子蟹前5对鳃Na⁺/K⁺-ATPase的酶活显著低于后3对鳃Na⁺/K⁺-ATPase的酶活。三疣梭子蟹对盐度变化的调节可分为被动应激期(酶活力下降)、主动调节期(酶活力逐渐上升)和适应期(酶活力稳定);三疣梭子蟹后3对鳃是离子转运、渗透压调节的主要部位。     

Electrical stimulation of spermatophore extrusion in the freshwater yabby (Cherax destructor)

A technique for collecting spermatophores from male yabbies (Cherax destructor) is described. This technique consists of applying an electrical stimulus of between 5 and 10 mA and 40–50 Hz around the coxa of the fifth walking leg, and was found to have a success rate of 76% in 100 males tested. Furthermore, this approach enabled the collection of spermatophores from intersex individuals, indicating that intersex animals have the ability to function as males.

Using this technique, it was shown that spermatophore development is correlated with water temperature and that it is possible to elicit spermatophores from males in the non-reproductive season simply by raising water temperatures. The ability to non-invasively collect spermatophores from yabbies will facilitate the development of artificial fertilization techniques in this species.     

钝缀锦蛤形态性状对活体质量的影响

基于钝缀锦蛤 (Tapes dorsatus) 规模化养殖面临的种苗供应问题,采用单因素对比实验法,开展了钝缀锦蛤苗种繁育关键技术研究,为其种苗大规模培育提供参考。结果表明：1) 在人工控温条件下,采用虾塘复合藻代替纯种单胞藻对亲本进行促熟,促熟率比对照组提高了282.6%。2) 通过升温加阴干诱导等一系列措施进行催产,亲贝催产率比对照组提高了50.9%。3) 通过添加益生菌构建有益微生态系统,育苗期间不换水,幼虫浮游期成活率、生长速度和稚贝育成率等指标均显著高于对照组。4) 采用立体采苗器结合池底进行立体附苗,稚贝育成率和单位面积产量分别提高了76.6%和76.5%。5) 按体质量5%上选的亲贝作为选育组,稚贝的壳长、体质量和稚贝育成率分别比对照组提高了6.67%、17.03%和8.43%;壳长和体质量变异系数分别降低了29.13%和55.29%;稚贝期壳长和体质量的现实遗传力“h²”分别达到0.65和0.72。采用研究建立的集成创新技术进行钝缀锦蛤人工育苗,可获得显著的经济效益,为实现种苗的规模化生产奠定了基础。