盐度对条石鲷摄食、生长和肌肉生化组成的影响

在水温为27～29℃下,进行了盐度(10、15、20、25、30、35)对条石鲷幼鱼Oplegnathus fasciatus (体质量为8.1～9.0 g)的摄食、生长和肌肉生化组成的影响试验.试验在18个体积为400L的黑色塑料圆桶中进行,共饲养28 d.结果表明:盐度对条石鲷幼鱼的生长有显著影响(P＜0.05),试验结束时,条石鲷的体质量、全长、体长在盐度为25、30时增加较多,与其他各组差异显著(P＜0.05);体质量特定生长率、体长特定生长率和食物转化率在盐度为30时最高,分别为2.90％/d、1.83％/d和97.50％,在盐度为10时最低,分别为2.15％/d、1.20％/d和78.85％,均与其他各组差异显著(P＜0.05);摄食率在盐度为25时最高,为3.00％,在盐度为35时最低,为2.59％,均与其他各组差异显著(P＜0.05);盐度对条石鲷肌肉中的水分、粗蛋白和粗脂肪含量影响不显著(P＞0.05).研究表明,条石鲷的适宜生长盐度为25～30.     

黄山浦溪河光唇鱼的性腺发育周年变化

采用组织切片法,对黄山浦溪河光唇鱼(Acrossocheilus fasciatus)的性腺发育、产卵时间和产卵类型等进行了研究。结果显示:其性腺的发育分为六6个时期,卵母细胞的发育分为5个时相。产卵时间始于四月,持续到八月。光唇鱼属于一次性产卵类型,每年成熟一次。在整个性腺发育过程中,雌性个体右侧性腺先于左侧性腺发育;雄性个体右侧性腺在整个发育过程中一直处于优势。     

温度对黄鳍东方鲀胚胎发育和仔鱼存活的影响

观察了不同温度条件下(20、23、26、29、32℃)黄鳍东方鲀受精卵的培育周期、孵化周期、孵化率和畸形率;并对黄鳍东方纯初孵仔鱼进行耐饥饿试验,测定其不投饵存活系数。试验结果表明,黄鳍东方纯受精卵孵化的适宜温度为20～26℃(最适温度为23℃);仔鱼生存的适宜温度为20～26℃(最适温度为23℃)。黄鳍东方鲀受精卵和仔鱼对温度这种环境因子的耐受范围基本相同。     

褶皱臂尾轮虫对提高暗纹东方鲀鱼苗成活率的作用

利用褶皱臂尾轮虫和暗纹东方鲀鱼苗在5‰的咸淡水中都能够存活的特点,用面包酵母培育褶皱臂尾轮虫经海水小球藻强化培育后在5‰的盐度条件下投喂暗纹东方鲀鱼苗,结果表明,褶皱臂尾轮虫较之淡水轮虫可使暗纹东方鲀鱼成活率显著提高。     

不同盐度对弓斑东方鲀消化酶活性的影响

本研究探讨了不同水体盐度对弓斑东方鲀α-淀粉酶、胃蛋白酶和胰蛋白酶活性的影响,同时得出最适于该鱼种消化吸收养分的盐度值,以发挥其生长潜力.试验用360尾鱼,分为4个处理(淡水对照,盐度8‰、18‰和35‰),每处理3个重复,每个重复30尾,通过15 d饲养试验,采样时间分别为:第1天、第4天、第7天和第15天.结果显示:随着盐度的增加,α-淀粉酶、胃蛋白酶和胰蛋白酶的活性有显著变化(P<0.05).在试验后期,α-淀粉酶活性在盐度18‰时显著高于盐度8‰和35‰的情况(P<0.05);胃蛋白酶活性则在8‰和18‰2种盐度下有显著差异(P<0.05);胰蛋白酶活性在8‰时最大,显著高于35‰和18‰处理(P<0.05).试验结果表明弓斑东方鲍饲养的水体盐度为8‰～18‰时能更有效的促进其消化酶的活性.     

苯酚对红鳍东方鲀肝胰脏CuZn-SOD和Mn-SOD基因表达的半定量分析

应用半定量RT-PCR法,研究苯酚对红鳍东方鲀(Takifugu rubripes)幼鱼肝胰脏CuZn-SOD和Mn-SOD基因相对表达量的影响。试验鱼饲养在苯酚浓度为0、0.18、0.32、0.56、1.00和1.35 mg/L的海水中,分别在苯酚暴露前和暴露4、8、12和16 d后取样。结果表明,在苯酚暴露前,鱼体肝胰脏中CuZn-SOD和Mn-SOD基因均有基础表达。在整个暴露时间(16 d)下,CuZn-SOD和Mn-SOD mRNA相对表达量呈现出逐渐上调的趋势,即苯酚诱导了两种基因的表达。在苯酚暴露第4天时,各浓度处理组CuZn-SOD mRNA和Mn-SOD mRNA的相对表达量均达峰值,显著高于暴露前水平(P0.05)。     

云斑裸颊虾虎鱼体内各组织河鲀毒素的含量

我国曾发生多起食用虾虎鱼的中毒事件。从发生中毒事件的广东湛江徐闻县西连镇采集了有毒虾虎鱼,经形态学鉴定为云斑裸颊虾虎鱼(Yongeichthys criniger),其体内含河鲀毒素。采用酶联免疫法测定了云斑裸颊虾虎鱼各组织河鲀毒素(tetrodotoxin,TTX)的含量,结果显示每千克组织的TTX含量由高到低依次为肝脏(69.954 mg)、卵巢(9.510 mg)、皮肤(8.937 mg)、肌肉(5.181 mg)、眼睛(3.321 mg)。比野生暗纹东方鲀(Takifugu fasciatus)相应组织TTX含量均要高,毒性强烈。     

养殖型暗纹东方鲀生长与发育特性

观测养殖型暗纹东方鲀，获得4个年龄组的生长数据和解剖资料。拟合出雌、雄的体长体重关系和生长方程，分析其肥满度、胸腹围特点以及性腺和肝脏发育特点。结果显示，养殖型暗纹东方鲀雌雄体长生长规律相似；但体重在2．5龄前雄鱼生长速度大于雌鱼，2．5龄后则相反。养殖暗纹东方鲀体型比野生暗纹东方纯肥胖。体重／体长和肥满度皆大于野生型。研究还发现，养殖暗纹东方鲀性腺发育不良和肝脏脂肪变性发生率高，且两者的发生存在一定关系，致使全人工育成的成鱼繁殖难以成功。     

Low-salinity tolerance of juvenile fugu <Emphasis Type="Italic">Takifugu rubripes</Emphasis>

ABSTRACT:   To study the adaptability of juvenile fugu Takifugu rubripes to low-salinity environments, fish were transferred from full-strength seawater (100% SW) to freshwater (FW) and 25, 50, 75 and 100% SW, and checked for mortality over 3 days. No mortality was observed in 25–100% SW, whereas all fish died in FW. In fish transferred to 25–100% SW, blood osmolality was maintained within a physiological range. To further explore the lower limit of salinity that fugu could tolerate, fish were transferred from 100% SW to FW and 1, 5, 10, 15 and 25% SW. All fish survived in 5–25% SW, but fish died in FW and 1% SW. In fish surviving transfer to FW and 1 and 5% SW, blood osmolality was decreased to a near sublethal level of approximately 300 mOsm/kg·H₂O. Therefore, the lower limit of salinity tolerance is estimated to lie between 5 and 10% SW. Preacclimation in 25% SW for 7 days did not essentially affect the survival salinity range. Although survival rates and blood osmolality were slightly improved by preacclimation in 25% SW, blood osmolality was markedly decreased in salinities less than 10% SW, as was seen in the direct transfer. Neither chloride cell morphology nor sodium-potassium adenosinetriphosphatase activity in the gills showed a significant change following transfer to low salinities. These findings indicate that fugu can be adapted to hypoosmotic environments to some extent, exerting hyperosmoregulatory ability, although chloride cells are less likely to absorb ions in hypoosmotic environments.     

Inhibitory modes of Kunitz and Bowman-Birk soybean trypsin inhibitors to tryptic and chymotryptic proteinases of tiger puffer and yellowtail

SUMMARY: An inhibitory effect of Kunitz and Bowman-Birk soybean trypsin inhibitors (K- and BB-SBTI) was investigated on tryptic and chymotryptic proteinases of a brood of tiger puffer Takifugu rubripes and yellowtail Seriola quinqueradiata . These assist to comprehend the differences in dietary soybean meal (SBM) utility by fish species and to develop low cost SBM diets with low contents of fish meal. The K-SBTI strongly inhibited tryptic proteinase and weakly inhibited chymotryptic proteinase from the hepatopancreas and intestine including pyloric ceca of the fishes. The BB-SBTI strongly inhibited both proteinases of the fishes. The K-SBTI inhibition for tryptic protease and the BB-SBTI inhibition for tryptic and chymotryptic proteases were relatively constant in tiger puffer with growth of 12–199 g bodyweight. In yellowtail with growth of 7–672 g bodyweight, the K-SBTI inhibition for tryptic protease and the BB-SBTI inhibition for chymotryptic protease were also relatively constant. The BB-SBTI inhibition for yellowtail tryptic protease typically fell in the stage from 7 g to 57 g bodyweight, and then decreased slightly or was maintained constantly. These results indicate that there are different inhibitory modes of K- and BB-SBTI and there is inter- and intraspecific diversity of tryptic protease conformation between the two species.