铜对刀鲚幼鱼的急性毒性及对肝抗氧化酶活性与组织结构的影响

采用静水生物测试法研究铜(Cu²⁺)对刀鲚(Coilia nasus)幼鱼的急性毒性并进行安全性评价。根据预实验结果, 设定0.3、0.54、0.96、1.68 和3 mg/L 5个CuSO₄浓度梯度进行急性暴露实验, 以肝组织超氧化物歧化酶(SOD)、过氧化氢酶(CAT)活性为指标, 并通过观察肝、鳃组织病理变化来研究Cu²⁺污染对刀鲚幼鱼的毒性效应。结果表明, 刀鲚幼鱼随Cu^{2 +} 浓度升高毒性效应逐渐增强, 24、48、72和96 h LC₅₀分别为1.087、1.062、1.042和0.967 mg/L, 安全质量浓度为0.009 67 mg/L。刀鲚幼鱼暴露24 h之后, 各Cu²⁺浓度处理组(0.1, 0.2, 0.3 mg/L) CAT活性、SOD活性显著提高(P<0.05); 暴露48 h后, 各组CAT活性下降, CAT活性均低于对照组, 下降幅度与Cu^{2 +}质量浓度呈正相关, SOD活性提高显著(P<0.05); 暴露72 h后, SOD活性有所下降, SOD活性均低于对照组(P<0.05)。1.68 mg/L和3 mg/L的Cu²⁺浓度对刀鲚幼鱼的鳃和肝都造成严重的损伤, 暴露在高浓度组(3 mg/L)中的刀鲚, 其鳃上皮细胞肿大变性, 鳃小片几乎全部脱落; 肝呈黄色, 超微结构发现肝细胞明显增大, 线粒体空泡化, 胞质中出现空泡和大量脂滴, 表明Cu²⁺可诱发刀鲚出现脂肪肝综合征。SOD、CAT活性变化以及鳃、肝结构变化都反映刀鲚幼鱼受伤害的程度, 可用作安全性风险评价的参考依据。     

乙纶网片热定型时间参数的选择

为了防备用合成纤维制作的网具变形,对构成网具的网片(或网衣)必须经过热定型处理,才能使结节目脚稳定。热定型的主要因素,是温度和时间。对于温度,生产单位比较注意,温度过高,易引起网片的熔融和粘结;温度太低,达不到定型的目的。然而对定型时间的长短,各单位很不相同。就乙纶网片而言,宁波渔网网厂是30分钟;上海绳网厂是20分钟;青岛网厂PE3×15的定型时间是6—8分钟。本实     

次致死浓度Cu2+对罗非鱼呼吸生理的影响

本文研究次致死浓度Cu~(2+)对罗非鱼呼吸生理的影响。通过比较15天里各污染组鱼呼吸频率、振幅和鳃盖运动的变化,得出罗非鱼异常鳃盖运动频率随Cu~(2+)浓度的增加而递增,咳嗽运动先于驱逐反射(expulsion reflex),提示鱼类的咳嗽运动和驱逐反射可作为次致死浓度下Cu~(2+)污染的敏感生物学监测指标。     

微波消解法在食品重金属残留量测定中的应用

用微波消解技术与灰化法分别处理蜜饯样品,用火焰原子吸收法测定样品中铜的含量,试验表明微波消解处理的样品与传统国标规定的灰化法处理的样品检测结果相对误差为1.94%,加标回收率在90.2%-101.7%,相对标准偏差为4.0%,其精密度、准确度符合分析要求。     

Improvement of copepod nutritional quality as live food for aquaculture: a review

In hatchery, an adequate supply of live food for first‐feeding fish larvae is essential and nutritional quality of live food organisms can be improved through nutrient enrichment. The use of live food organisms, especially at first feeding, is a requisite for most marine fish larvae. In ocean, marine fish larvae primarily feed on copepods, but the production protocols of copepods as live food is underdeveloped in hatchery. As the food ingestion and the digestive system of copepods are different from other live food organisms (e.g. rotifers), the nutrition enrichment procedures with emulsion oil used in rotifers is not effective on copepods. This review focuses on alteration of nutrient composition of copepods through manipulation of copepod food before they are fed to fish larvae. Specifically, we discuss the relationship between the changes of fatty acid compositions in dietary algae and in copepods. The review links nutrient supply to copepods and the change of nutrition in copepods and suggests ways to improve copepod nutrition in hatcheries.     

Effects of copper on survival and growth of larval false clown anemonefish <Emphasis Type="Italic">Amphiprion ocellaris</Emphasis>

ABSTRACT:   Larval false clown anemonefish of about 12 h after hatching were fed newly-hatched brine shrimp nauplii in natural (control) and copper-added seawater (40–640 µg–Cu/L) at 26.5 ± 0.5°C for 14 days. Survival rate of the fish increased with increasing copper concentrations up to 160 µg–Cu/L. The rates at 80 and 160 µg–Cu/L were 65 and 80%, respectively, and were significantly higher than that of the control (30%). A positive effect of copper addition on the survival rate was also observed in the other rearing experiment with the fish from seven different spawning chances. Growth rate of the survival fish was not affected by copper concentrations. The copper concentration of the survived fish increased with increasing copper concentrations in the rearing water.     

Specific accumulation of heavy metals in squid collected from offshore Korean waters: preliminary results for offshore biomonitoring and food safety assessment

ABSTRACT:   Japanese common squid Todarodes pacificus collected from the East Sea/Sea of Japan were analyzed for cadmium, zinc and copper to elucidate the specific accumulation of heavy metals in various organs of squid of varying size and sex. There was no relationship between the size and sex of squid and the concentrations of heavy metals in various organs. Amongst organs, the liver contained the highest concentrations of all metals and the mantle had the lowest concentrations. In the liver and gills, concentrations of copper were higher than the other metals because of the existence of copper in hemocyanin in the blood. Cadmium showed the highest ratios (L/M) of the concentrations in the liver and in the mantle, even though cadmium in liver had lower concentrations than copper and zinc. This indicates that cephalopods constitute an important source of cadmium for cephalopod predators. The results show that the Japanese common squid is a useful bioindicator of metal pollution in offshore Korean waters.     

五种理化因子对眼斑拟石首鱼苗种的影响

报道了眼斑拟石首鱼苗种对盐度、有效氯、高锰酸钾、硫酸铜耐受力的实验,测定了它的呼吸耗氧量和窒息点：缺氧浮头时的溶氧值为1．86mg／L,窒息点范围为0．79～0．38mg／L。实验表明：有效氯毒性极强,高锰酸钾次之,CuSO4·5H2O较弱。采用1×10(－6)以下的CuSO4·5H2O处理眼斑拟石首鱼鱼苗是安全的。     

围网沉降载荷分布

在平面网片上装配沉子的网片沉降系列试验表明,在围网网衣上装配沉子能使下纲得到更快的平均沉降速度,这取决于网衣载荷的装配位置和载荷比。第２条沉子纲的最佳装配位置应在网衣中下部,网高的０．５３６～０．８５０范围内,具体取决于网衣载荷与总载荷之比,比值越大,装配位置越下移。网衣载荷可分解过重的下纲载荷,减轻括纲绞机拉力,有利于网壁下垂保持良好网形。     

中国沿海底层拖网网型分析

作者根据中国沿海现有几十种较有代表性的底层有翼单囊拖网网具资料,统计了大量的网具设计参数,并根据拖网的结构特征和作业性能来分析研究结果,认为在中国沿海拖网渔业生产中,使用较多、效果良好并具有一定代表性的底层有翼单囊拖网的网型,主要有尾拖型、疏目型、改进疏目型和编结型四种,并认为这四种网型的作业性能可简单地归纳为:改进疏目型为高口中速;尾拖型为中口中速;编结型为中口高速;疏目型为低口快速。