南海北部黄鳍金枪鱼幼鱼和成鱼鳃的组织学比较研究

本研究运用光学显微镜、扫描电镜以及透射电镜技术研究了南海北部黄鳍金枪鱼(Thunnus albacares)幼鱼和成鱼鳃的显微组织结构、鳃表面超微结构和鳃小片内部超微结构特点。结果表明, 黄鳍金枪鱼鳃丝顶端弯曲, 鳃弓、 鳃丝和鳃耙表面具有不同类型的细胞。表面超微结构研究显示黄鳍金枪鱼的鳃具有高的片层密度、独特的斜向血流模式以及鳃的融合特性, 幼鱼和成鱼鳃结构之间存在显著不同。鳃小片内部超微结构研究显示鳃扁平上皮细胞覆盖于鳃丝和鳃小片表面, 顶端存在微绒毛或微脊结构, 相对幼鱼, 成鱼具有高的细胞质密度; 离子细胞主要分布于鳃小片以及鳃小片基部, 幼鱼离子细胞顶端开口为微绒毛, 成鱼为小坑状。本研究阐明了黄鳍金枪鱼幼鱼和成鱼鳃的组织结构, 丰富了黄鳍金枪鱼鳃的基础生物学资料, 为研究高速游泳鱼类鳃的形态特征与其高速游泳习性之间的关系提供了参考。     

盐度对条石鲷幼鱼Na+/K+-ATP酶活力的影响

研究了盐度变化对条石鲷幼鱼鳃、肾脏和肝脏中Na⁺/K⁺-ATP酶活力的影响。经不同盐度(8、18、28、38、48)的处理,条石鲷幼鱼3种组织Na⁺/K⁺-ATP酶活力均受到不同程度的影响。经低盐度(8和18)处理的幼鱼鳃Na⁺/K⁺-ATP酶活力在前6 h略微增加,然后逐渐降低,在处理24 h时下降到最低,之后又开始增加。经高盐度(38和48)处理时,鳃中Na⁺/K⁺-ATP酶活力在前6 h有所降低,然后迅速升高,并在处理24 h时达到最大,之后酶活力逐渐降低,并在处理96 h后与对照组无显著性差异(P>0.05)。所有盐度处理组幼鱼肾脏Na⁺/K⁺-ATP酶活力在处理开始6 h均稍有增加,而从处理6 h开始降低,在处理24 h下降到最低,此后酶活力又呈现增加的趋势。在盐度为8的处理组中,肝脏Na⁺/K⁺-ATP酶活力与肾脏中变化趋势相似,而其它3组则逐渐降低,在处理24 h时达到最低,之后又逐渐增加。结果表明,条石鲷幼鱼适盐范围广,具有较强的渗透压调节能力。3种组织的Na⁺/K⁺-ATP酶活力酶活性在盐度为18～38的范围内变化不明显,而在8和48的盐度下变化较大,最终酶活力均高于对照组。与肾脏相比,盐度变化对鳃和肝脏Na⁺/K⁺-ATP酶活力的影响较大。     

菲胁迫对红鳍笛鲷急、慢性毒性效应的研究

为了解海洋菲污染对海洋水产经济鱼类的毒性及致毒机理,在实验室条件下采用半静态毒性实验研究了菲对红鳍笛鲷的96 h急性毒性,同时分析和比较了不同浓度(10.0、50.0、250.0μg/L)菲胁迫96 h后红鳍笛鲷肝脏、鳃中超氧化物歧化酶(SOD)活力,丙二醛(MDA)含量以及脑组织中乙酰胆碱脂酶(AChE)活力的变化。结果表明,菲对红鳍笛鲷幼鱼的24、48和96 h半致死浓度(LC50)分别为4.65、3.46和3.17 mg/L,安全浓度为0.317 mg/L。在整个胁迫过程中,低浓度(10.0μg/L)菲可诱导红鳍笛鲷肝脏和鳃组织SOD活力显著性升高(P<0.05);随着浓度升高,50.0和250.0μg/L浓度组肝脏SOD活力呈抑制-诱导的波动变化,鳃SOD活力的变化则呈抑制-诱导-抑制的趋势。随着菲曝露时间延长,各浓度组红鳍笛鲷肝脏和鳃组织的MDA含量明显升高;脑组织中AChE活力表现为先升高后降低的的趋势。结果提示,菲对红鳍笛鲷具有很强的毒性,可在96 h内通过氧化损伤途径对机体产生毒性作用,鉴于SOD、MDA、AChE指标对菲的高度敏感特点,可以用其作为生物标志物来指示多环芳烃类污染物对水生生物的...     

星康吉鳗形态性状与体重的通径分析及生长曲线拟合

为探明星康吉鳗（Conger myriaster）形态性状和体重的关系，测定了体重（Y）及全长（X₁）、肛长（X₂）、尾长（X₃）、头长（X₄）、吻长（X₅）、眼径（X₆）、眼后头长（X₇）、背鳍前长（X₈）、躯干长（X₉）、头宽（X₁₀）、眼间距（X₁₁）等11个形态性状，通过相关分析、通径分析、回归分析等方法研究了形态性状对体重的影响；通过曲线拟合获得4个形态性状与体重的最佳拟合模型。结果表明，星康吉鳗各形态性状之间以及形态性状与体重之间均呈极显著正相关关系（P< 0.01）。相关分析发现肛长（X₂）与体重的相关系数最大（0.970）；通径分析发现肛长（X₂）对体重的直接作用最大（0.450），头宽（X₁₀）通过肛长（X₂）对体重的间接作用最大（0.431）；决定系数分析发现，肛长（X₂）对体重的直接决定系数最大（0.203），肛长（X₂）和头宽（X₁₀）的共同决定系数最大（0.172）。形态性状（X）与体重（Y）的多元回归方程为Y=-113.859+6.481X₂+49.213X₆+11.514X₇+20.145X₁₀（R²=0.954）。星康吉鳗肛长（X₂）、眼后头长（X₇）、头宽（X₁₀）与体重的最佳拟合模型为指数函数，模型方程分别为Y=1.466e^0.287X、Y=1.435e^1.328X、Y=1.970e^1.974X，眼径（X₆）与体重的最佳拟合模型为线性，方程为Y=-77.460+222.093X。结论认为，在星康吉鳗选育时，应以肛长（X₂）和头宽（X₁₀）为主要选择性状，以眼径（X₆）和眼后头长（X₇）为辅助选择性状。     

四角蛤蜊形态性状对重量性状的影响效果分析

以随机选取的123只野生四角蛤蜊为材料,对其形态性状(壳长X₁、壳高X₂、壳宽X₃)和重量性状(活体质量Y、软体质量Z)进行了测量,然后运用相关分析、通径分析和回归分析等分析方法研究形态性状对重量性状的影响。结果表明,5个数量性状间的相关系数均达到极显著水平(P<0.01)。形态性状对活体质量和软体质量的直接影响依次为壳宽>壳长>壳高。壳宽是影响活体质量和软体质量的主要因素,其决定系数分别为0.302 5和0.224 7。多元回归分析建立了估计活体质量、软体质量的最优回归方程:Y=-19.537+0.244X₁+0.266X₂+0.732X₃、Z=-2.456+0.035X₁+0.035X₂+0.089X₃。     

强壮箭虫摄食生态的实验研究

实验研究了强壮箭虫对几种食物的摄食选择性和几种生态因子对其摄食率的影响，以及摄食的昼夜节律。结果表明，强壮箭虫首先选食蒙古裸腹，其次哲水蚤，再其次猛水蚤，不摄食褶皱臂尾轮虫。食物密度、温度和盐度对其摄食率均有极显著的影响，其关系式分别 为（1）Y =-0.0394X^{2+1.5861X-4.0500(R2=0.9235)，（2）Y=-0.0514X2+1.3238X+7.3833(R2=0.9510) ，（3）Y=-0.0275X2+1.3992X-6.3571(R2=0.9041)。摄食的最适食物密度为每升100个裸腹（生物量15～20 mg·L-1），摄食率为11.9 ind·d-1；摄食的最适水温为12.9 ℃，摄食率15.9 ind·d-1；摄食的最适盐度为25.4，摄食率为11.4 ind·d-1。强壮箭虫在夜间或弱光条件下，摄食较为强烈，早晨8点到12点摄食率最低，午后4点到8点达到摄食高峰。}     

邻苯二甲酸二丁酯对红鳍笛鲷幼鱼的胁迫效应

为了探讨邻苯二甲酸二丁酯(DBP)对红鳍笛鲷(Lutjanus erythropterus)幼鱼的胁迫效应,于DBP暴露后0、6、12、24、48和96 h时检测红鳍笛鲷鳃、肝和脑组织中超氧化物歧化酶(SOD)、丙二醛(MDA)和乙酰胆碱酯酶(AChE)活性。结果表明,DBP对红鳍笛鲷的24 h、48 h和96 h LC50分别为7.10 mg/L、6.98 mg/L和6.66 mg/L,安全质量浓度为2.04 mg/L。随着浓度增加,鳃组织中的SOD酶活性表现为先升高后下降,具有明显的时间效应;肝组织中的SOD酶活性在0.5 mg/L和2.0 mg/L浓度组交替表现为升高和降低,与对照组比较有显著性差异(P<0.05);而0.125 mg/L浓度组肝SOD没有明显变化。鳃组织中MDA含量在DBP暴露6 h后显著性增加(P<0.05),之后随时间延长而下降;DBP暴露6 h和12 h后,0.5 mg/L和2.0 mg/L浓度组肝组织中的MDA含量都显著升高(P<0.05),之后随时间延长MDA含量下降并趋于稳定。与对照组比较,DBP暴露48 h后,红鳍笛鲷脑组织中AChE酶活性显著升高(P<0.01),96 ...     

聚维酮碘、硫酸铜及氯氰菊酯对漠斑牙鲆幼鱼的急性毒性试验

研究了聚维酮碘、硫酸铜、高效氯氰菊酯三种药物在一定条件下对漠斑牙鲆幼鱼(70日龄)的毒性效应。结果表明:聚维酮碘的安全浓度为4.062g/mL;24h半致死浓度为55.296 mg/L,48h半致死浓度为34.560mg/L。硫酸铜的安全浓度为0.667mg/L,24h半致死浓度为2.812mg/L,48h半致死浓度为2.600mg/L。高效氯氰菊酯的安全浓度为0.079μg/L,24h半致死浓度为7.112μg/L,48h半致死浓度为2.371μg/L。     

壬基酚对1月龄泥鳅的急性毒性及鳃、肝脏组织学损伤研究

为了研究壬基酚(Nonylphenol,NP)对淡水鱼类幼鱼的急性毒性及相关组织的损伤效应,选取平均体质量6.0 g、平均体长9.2 cm的1月龄泥鳅(Misgurnus anguillicaudatus)为受试材料,检测壬基酚对幼鱼的急性毒性效应,按等对数间距法,将NP设置为1.69、1.95、2.25、2.60、3.00 mg/L共计5个浓度处理组进行急性毒性实验,同时设置空白对照组,每组设3个平行样,每个样投放10条泥鳅,观察NP对泥鳅鳃、肝脏组织结构的损伤变化,并统计半致死浓度和安全浓度。结果表明,壬基酚对1月龄泥鳅24、48、72、96 h的半致死质量浓度分别为3.722、2.939、2.466、2.175 mg/L,安全浓度为0.550 mg/L。组织学切片观察显示,壬基酚高浓度处理使泥鳅鳃小片细胞脱落严重,鳃小片变细;泥鳅肝脏细胞出现空泡、肿大、核脱落等现象,细胞间隙变大,边界模糊。实验表明,壬基酚属于高毒性酚类污染物,对1月龄泥鳅的毒性作用随着暴露浓度增加、作用时间的延长而增强,在高剂量暴露下可造成泥鳅鳃和肝脏组织的严重损伤。     

铜对细鳞鲑幼鱼鳃和肝组织的急性毒性

在水温(16±0.5)℃下,采用静水实验法研究不同浓度的铜离子对体质量(35.8±9.6)g的细鳞鲑Brachymystaxlenok幼鱼鳃和肝脏的急性毒性,铜离子浓度为24h半致死浓度(LC_(50))的1/4倍、1/2倍,及1倍。结果表明:铜胁迫初期细鳞鲑幼鱼的鳃充血而颜色而变暗,后期鳃血管和细胞病变,颜色变浅。鳃丝先弯曲,然后溃烂,最后脱落;肝脏出血、肿大,切片显示肝脏细胞空泡化,后期可以看到坏死的细胞核。铜离子对细鳞鲑幼鱼的鳃和肝脏组织有明显的破坏作用,是铜急性中毒致死的原因之一。     

Acute responses of juvenile cobia Rachycentron canadum (Linnaeus 1766) to acid stress

Fish are potentially submitted to water acidification when reared in recirculating aquaculture systems. This study evaluated the responses of juvenile cobia Rachycentron canadum after acute exposure to acid water. Juvenile cobia (12.6 ± 0.5 g; 14.2 ± 0.2 cm) were acutely exposed to four pH levels (7.9 (control), 6.5, 6.0, and 5.5). After 24 h of exposure to different pH values, fish were sampled for physiological and histopathological evaluation. Acid water affected physiological parameters and induced morphological histopathologies on gill and skin of juvenile cobia, and these effects were more conspicuous with decreasing pH values. Acid stress induced blood acidosis in juvenile cobia, coupled to a decrease in bicarbonate (HCO₃^?) and saturated O₂ (sO₂) in fish blood. On the other hand, haematocrit, haemoglobin and glucose concentration increased their values (P < 0.01) comparing to control level. Hyperplasia with completely fusion of secondary lamella was observed in all pH treatments (6.5. 6.0 and 5.5), while telangiectasia and proliferation of chloride cells were present for fish exposed to pH 6.0 and 5.5. In skin hyperplasia and hypertrophy of mucous cells, necrosis of these cells for fish exposed to pH 6.0 and 5.5 was observed. The results of this study demonstrate that acute acid water exposition affected physiology and histopathology in juvenile cobia, especially at pH values below 6.5. Accordingly, particular attention must be given to pH during cobia reared in recirculating aquaculture.     

不同时期牙鲆形态性状对体重影响的通径分析及曲线拟合研究

以8月龄与14月龄的养殖牙鲆(Paralichthys olivaceus)为研究对象,分别测定体重(Y)和22个形态性状,对各性状进行相关分析,并建立多元回归方程,对各形态性状对体重的影响效果进行通径分析。分别以进入回归方程的各形态性状作为自变量,体重为因变量进行曲线模型拟合,筛选最优拟合模型。结果显示:(1)在不同生长阶段,相同形态性状与体重的相关性存在差异。(2)8月龄阶段,X_(18)(腹鳍基部到背鳍终点的直线距离)、X_4(体宽)和X_(11)(背鳍起点到臀鳍起点的直线距离)对体重的通径系数达到极显著水平(P0.01),14月龄阶段,X_(18),X_(14)(背鳍终点到臀鳍终点的直线距离)和X_9(尾柄长)对体重的通径系数达到显著水平(P0.05),由此可知,不同生长阶段,影响体重的形态性状不尽相同。8月龄和14月龄牙鲆形态性状对体重的多元回归方程分别为:Y=-119.541+7.191X_(18)+10.135X_4+7.197X_(11);Y=-484.931+31.959X_(18)+81.928X_(14)-17.899X_9。(3)8月龄阶段,将回归模型中的3个自变量分别与体重进行模型拟合,最优拟合模型均为线性模型,分别为:Y=-117.866+15.724X_(18);Y=-94.579+24.763X_4;Y=-100.602+33.184X_(11);14月龄阶段,将回归模型中的3个形态性状分别与体重进行模型拟合,最优拟合模型均为幂函数模型,分别为:Y=0.036X_(18)~(3.063);Y=0.095X_(14)~(2.587);Y=62.249X_9~(1.584)。本次研究表明,在牙鲆的不同生长时期,影响体重的主要形态性状不同,两阶段适用的最优拟合模型也不同,这为牙鲆不同时期的选择育种工作提供了理论依据。     

Extraction Optimization for Phlorotannin Recovery from the Edible Brown Seaweed Ecklonia Cava

Phlorotannins, marine polyphenols from the brown seaweeds, are a promising biologically active substance. This study aimed to optimize the extraction conditions for phlorotannin recovery from the brown seaweed Ecklonia cava using response surface methodology. Ethanol concentration (X₁, %), extraction temperature (X₂, °C), and extraction time (X₃, h) were chosen as independent variables. The dependent variables were total phlorotannin content (TPhC; Y₁) and yield of phlorotannins (Y₂). Estimated optimal conditions were as follows: TPhC (Y₁): X₁ = 95%, X₂ = 80°C, X₃ = 22.8 h, and yield of phlorotannins (Y₂): X₁ = 88.3%, X₂ = 80°C, X₃ = 24 h. Predicted values of dependent variables under each optimal condition were TPhC (Y₁) = 570.2 mg phloroglucinol equivalents/g (mg PGE/g, dry basis) and yield of phlorotannins (Y₂) = 7.8% and were similar to the experimental values. In addition, content of dieckol, which is known as an indicator of phlorotannin products, was measured. Dieckol contents of the phlorotannin extracts with the highest (565.7 mg PGE/g) and lowest (315.4 mg PGE/g) TPhC were 49.1 and 34.4 mg/g (dry basis), respectively.     

Effect of Lead on Survival,Osmoregulation, and Histological Changes of the Gills of the White Shrimp,Litopenaeus vannamei,Boone, 1931

The purpose of this study was to evaluate the acute toxicity of lead for different life stages of shrimp, Litopenaeus vannamei, and to determine the effect of its sublethal concentrations on osmoregulatory capacity (OC) as well as the possible histological alteration in the gills of juvenile shrimp. The 24‐, 48‐, and 96‐h LC₅₀ values for lead to L. vannamei increased progressively with increasing life stage, from nauplii < zoeae < mysis < postlarvae < juvenile. After 15‐d exposure to 3.25, 6.50, and 9.75 mg Pb/L, the OC values of exposed shrimp were reduced by 39, 73, and 157%, respectively compared to control animals. Compared to controls, the lead concentrations in gill tissues increased significantly by 127,500, 137,500, and 141,000% in shrimps exposed to 3.25, 6.50, and 9.75 mg Pb/L, respectively. After lead exposure, hemocytic congestion in efferent vessels and multiple hyperplasia were observed in gill filaments, resulting in narrowed hemolymphatic lacuna. The histopathological effects increased with increasing Pb concentration.     

Parasites, pathological conditions and mortality in QX-resistant and wild-caught Sydney rock oysters, Saccostrea glomerata

Differences in the survival of QX-resistant fifth generation (QXR₅) and wild-caught (Wild-Caught) Sydney rock oysters were assessed over the QX-disease risk period in the Pimpama River, SE Queensland. Cumulative mortality of Wild-Caught oysters (31.7%) was significantly greater than QXR₅ oysters (0.0%) over the 118 days of the experiment. PCR and histological results showed that Wild-Caught oyster did not die from QX disease. Histology revealed oysters were infected with disseminating hemocytic neoplasia, a Steinhausia-like infection, a Rickettsia-like organism infecting epithelial cells of the gill, digenean flukes encysted in the gonadal tissue and a gill response to an unknown toxin. The cause of mortality is attributed to disseminating hemocytic neoplasia.     

An evaluation of phytase for Channel catfish (Ictalurus punctatus) fed all plant‐protein diet: Growth performance,nutrient utilization and P equivalency value

This study evaluated the effect and phosphorus equivalency value of dietary microbial phytase based on growth performance and nutrient utilization of Channel catfish (Ictalurus punctatus). An all plant‐protein basal diet containing 7.9 g/kg total Phosphorus (P) (Phytate P of 4.5 g/kg) was supplemented with graded levels 0, 300, 500, 1,000, 1,500 and 2,000 U phytase/kg of diet or with 3, 5, 8, 12 g/kg of Ca(H₂PO₄)₂, namely with 0.7, 1.2, 2.0, 3.09 g/kg P as Ca(H₂PO₄)₂. Triplicate groups of Channel catfish (Ictalurus punctatus) juveniles (initial weight, 1.70 ± 0.04 g) were fed the experiment diets for 90 days. The results indicated that dietary phytase supplementation significantly improved growth performance, apparent digestibility coefficient of P and P retention, and decreased feed conversion ratio (FCR), faecal P content and P excretion per gain. Line relation was found between the effects of P and phytase supplementation levels, and the linear response equations of the effects of P and phytase levels were generated and used to calculate the P equivalency values. The average function of P equivalency values (Y, g/kg) of microbial phytase (X, U/kg of diet) was developed: Y = 0.1695 + 0.0021X; R² = 0.996. The results showed that about 0.38 g of P/kg diet was released by per 100 U of phytase over the range of 300–2,000 U of phytase/kg diet for Channel catfish (Ictalurus punctatus) fed all plant‐protein diet.