不同孵化方式、培育密度和附着基对瘤背石磺人工繁育的影响

为提高瘤背石磺(Onchidium struma)在胚胎发育和幼虫发育过程中受精卵的孵化速率和幼虫的存活率, 本试验模拟滩涂生态环境对瘤背石磺亲贝进行人工养殖, 并促使其交配产卵。将采集的瘤背石磺新鲜卵块置于盐度18, 水温25～26 ℃的水体中进行孵化。比较3 种不同孵化方式对孵化速率的影响, 并研究不同孔径(1.0～1.5 mm)海绵附着基和不同培育密度对幼虫存活率的影响, 同时结合幼虫在各水层中分布的变化规律, 探索瘤背石磺胚胎发育和幼虫发育过程的关键技术。结果显示, 采用3 种方式(“喷淋”、“露空”和“梯笼”)孵化, 受精卵至出膜面盘幼虫期所需时间分别为8、6 和9 d; 大孔径(1.2～1.5 mm)海绵组对幼虫的附着效果较好, 存活率显著高于小孔径(1.0～1.2 mm)海绵组(P<0.05),且两者均显著高于未添加附着基组(P<0.05); 存活率与不同培育密度的二次多项式回归分析显示, 瘤背石磺幼虫培育密度为55～61 个/mL 时存活率较高。上述结果表明, “露空”孵化方式能显著缩短瘤背石磺孵化所需时间; 在生产过程中, 幼虫培育密度以55～61 个/mL 为宜, 面盘幼虫期投放大孔径海绵作为幼虫附着基能显著提高幼虫存活率且能明显缩短胚胎发育和幼虫发育所需时间。     

盐度对三疣梭子蟹生长、肌肉组成及蛋白酶活性的影响

设置11、17、23、29、35共5个盐度梯度的水体,饲养平均初重为(14.45±1.36)g的三疣梭子蟹(Portunus trituberculatus)30d,研究盐度对三疣梭子蟹生长、肌肉组成、肝胰腺和胃中蛋白酶活性的影响。结果表明,在11~29的盐度范围内,三疣梭子蟹生长速度、肝胰腺和胃中蛋白酶活性均随盐度升高而升高,盐度上升到35时上述各指标又都显著下降(P0.05);盐度对肌肉含水量影响不显著(P0.05),但17以下盐度组的肌肉含水量高于23以上盐度组;盐度对肌肉粗蛋白和粗脂肪含量影响显著(P0.05),29盐度组肌肉蛋白显著高于17以下盐度组(P0.05),在试验盐度范围内,肌肉粗脂肪含量随盐度上升显著升高(P0.05)。     

浮游植物叶绿素a 含量测定方法的比较及优化

比较了丙酮萃取法和乙醇-超声波法测定水体中叶绿素a的方法,并对后者进行优化。结果显示,乙醇-超声波法的萃取效率显著地高于丙酮法的效率,两种方法的相关系数为0.9990,回归方程为Chla丙酮=1.0932Chla乙醇–11.677。优化后的乙醇-超声波法的最佳处理条件为:带样滤膜–20℃,冰冻24 h以上,加适量80℃热乙醇在80℃水浴中解冻,经超声振荡处理3 min后,室温黑暗条件下萃取6 h,再离心定容测定。     

中华绒螯蟹鳃上皮Na+-K+-ATPase性质的研究

本文研究了中华绒螯蟹鳃上皮Na^ -K^ -ATPase的性质，并比较了各对鳃丝Na^ -K^ -ATPase的活性大小。结果表明：中华绒螯蟹鳃上皮Na^ -K^ -ATPase的最适温度为40℃，温度高于45℃时酶活急剧下降；最适pH为8．0，并且其活力对pH的变化非常敏感，当pH小于7．5或大于8、25时酶活急剧下降；最适底物和Na^-，K^ ，Mg^2 浓度分别为1．5，75，15，6mmol／l；反应介质中乌本苷浓度达到2mmol／l时，Na^ -K^ -ATPase的活力完全被抑制；中华绒螯蟹后3对鳃丝Na^--K^ -ATPase的活力极显著高于前5对鳃丝的酶活力。     

Growth and antioxidant status of oriental river prawn <Emphasis Type="Italic">Macrobrachium nipponense</Emphasis> fed with diets containing vitamin E

A feeding trial was carried out to investigate the dietary vitamin E requirement of the oriental river prawn Macrobrachium nipponense (weight of 0.3–0.4 g) and its effect role on antioxidant activity. Prawns were fed with seven levels of vitamin E (0, 25, 50, 75, 100, 200, and 400 mg/kg diet) for 60 days. The results show that dietary vitamin E supplementation could significantly increased the prawn weight (P < 0.05). The activity of superoxide dismutase (SOD) in the hepatopancreas was significantly higher in prawns fed with diets supplemented with ≤75 mg/kg vitamin E than in those fed with diets supplemented with 100–400 mg/kg vitamin E (P < 0.05). The activity of catalase (CAT) in the hepatopancreas decreased significantly as dietary vitamin E supplementation increased (P < 0.05), and no significant difference was detected in glutathione peroxidase (GSH-Px) activity between different dietary groups (P >0.05). The contents of vitamin E in the hepatopancreas and in the muscle increased with increasing dietary vitamin E. There was a linear correlation between the vitamin E level in diet and that in muscle, and between the vitamin E level in diet and that in the hepatopancreas. All the above results indicated that dietary vitamin E can be stored in the hepatopancreas and muscle and lower both the activities of SOD and CAT in the hepatopancreas, suggesting that it is a potential antioxidant in M. nipponense. Broken line analysis conducted on the weight gains of prawns in each diet group showed that the dietary vitamin E requirement for maximum growth is 94.10 mg/kg.