斑点叉尾与团头鲂池塘混养技术

在面积为6 667m2的池塘混养     

长吻行为的初步观察

在长吻     

汉江中游银的繁殖生物学

初步研究了2004年5～8月汉江鱼类资源调查中采集的银(鱼句)的繁殖生物学.汉江中游的银(鱼句)5月中旬至8月上旬繁殖,成熟亲鱼个体全长6.5～16cm,平均(9.25±2.34)cm,平均体重(9.51±3.28)g;亲鱼97.5%为2～3龄鱼,2.5%为4龄鱼,均无明显的第二性征;左右两性腺等重,绝对怀卵量平均(4 823±1 023)粒,相对怀卵量平均(365±43)粒/g,成熟卵粒径(0.98±0.11)mm;属一次产卵类型.繁殖亲鱼评估数量为15.26万尾,产卵3.68亿粒,有谷城、茨河等7个产卵场;产卵水温17.5～27℃,多处于两个江水上升峰之间的波谷期产卵;卵粒吸水膨胀后具双层卵膜,外膜具微粘性,是漂流性卵系中唯一具双膜的鱼卵;卵外膜直径(3.6±0.42)mm,内膜直径(1.88±0.12)mm;胚胎发育分为4个阶段、50个发育期.     

花人繁子代亲鱼个体生殖力研究

比较了人工繁殖的一冬龄、二冬龄花     

斑点叉尾80:20池塘养殖试验报告

本试验目的是为了探索斑点叉尾     

生物水净化剂在长吻、异育银鲫养殖中的应用

2003年10月进行试验.试验池为136m2圆形长吻(鱼危)养殖池一个,44m2圆形异育银鲫养殖池一个,试验期间按设计要求加入生物水净化剂,24 h采集水样一次,历时7 d.测定项目包括水温、透明度、pH值、电导率、总硬度、溶解氧、氨氮、硝酸盐氮、亚硝酸盐氮、总磷、正磷酸盐、化学耗氧量等.结果显示异育银鲫池和长吻(鱼危)养殖池的透明度升高了10.2%和9.4%,氨氮下降了24.5%和34.1%,硝酸盐氮下降了33.8%和20.4%,正磷酸盐下降了50.0%和35.0%,化学耗氧量下降了36.3%和28.6%.     

黄带Seriola aureovittata(Temminck et Schlegel)在浙江海区的引进及养殖越冬试验

黄带     

17β-雌二醇和甲基睾酮对离体长臀脑垂体促性腺激素分泌的影响

性类固醇激素对性腺发育期间的鱼类促性腺激素(GTH)分泌有负反馈作用,而对性未成熟的鱼类GTH分泌有正反馈作用.本实验选取性腺发育中期的长臀(鱼危)(Cranoglanis bouderius)进行研究,将实验用鱼分成4组(实验重复3次,每组共用6尾鱼,)①持续性17β-雌二醇(17β-Estradiol,E2)处理;②E2在注入促性腺激素释放激素类似物(Analogue of gonadotropin-releasing hormone,GnRH-A)脉冲刺激的处理;③持续性甲基睾酮(17α-methyltestosterone,MT)处理;④MT在注入GnRH-A脉冲刺激的处理;采用离体灌流孵育和GTH放射免疫测定的方法研究E2和MT对长臀(鱼危)脑垂体GTH分泌的影响.持续性的E2(1μmol/L)处理能显著性地抑制长臀(鱼危)脑垂体碎片基础GTH的分泌,而持续性的MT(1μmmol/L)处理能抑制长臀(鱼危)3脑垂体碎片基础GTH的分泌,同时E2和MT处理能抑制GnRH-A刺激的GTH分泌,而高浓度的E2和MT处理(10μmol/L)要比低浓度的E2和MT处理(0.1μmol/L)对长臀(鱼危)脑垂体碎片基础GTH释放抑制能力强.这些结果表明,在离体实验中,E2和MT对性腺发育中期的长臀(鱼危)脑垂体的GTH的分泌具有负反馈的作用,并且可能直接参与了长臀(鱼危)脑垂体的GTH调节.     

读者.作者.编者

本刊本着“应用为主，面向基层，源于实践，指导生产”的方针，为了更好地为读者服务，及时交流科技信息，做好咨询工作，反映广大读者对本刊的批评意见和合理化建议，特增设《读者．作者．编者》栏目，敬请广大读者、作者给予热情支持，踊跃投稿，使她真正发挥广大作者、读者与编辑部的桥梁作用。     

简讯15则

●利用优势,龙溪柳塘水库形成经济实体福建省龙溪县柳塘水库充分利用库区自然资源、人力资源和设备条件的优势,进行全方位开发和多层次经营,使水库形成综合经营的经济实体。柳塘水库养鱼水面2400亩,水质肥沃,适宜发展水库渔业。水库运行10年来,年均养鱼产值12万元。该库利用周围的山坡地开垦     

Effects of <Emphasis Type="Italic">Euphorbia hirta</Emphasis> plant leaf extract on growth performance,hematological and organosomatic indices of hybrid catfish, <Emphasis Type="Italic">Clarias macrocephalus </Emphasis>× <Emphasis Type="Italic">C. gariepinus</Emphasis>

This study was conducted to evaluate the effects of Euphorbia hirta leaf extract on the growth performance, hematological and organosomatic indices of hybrid catfish, Clarias macrocephalus?×?C. gariepinus. The fish were treated with 0 (control), 300, 500 and 800 mg/kg (ppm) for 90 days. The weight gain, average daily growth rate, and specific growth rate were at significantly higher levels in fish from all the treatment groups on days 75 and 90, while the feed efficiency and protein efficiency ratio were consistently higher in fish from all the treatment groups from day 60 up until day 90. The feed conversion rate significantly decreased from day 60 until day 90 in all treatment groups when compared with the control group, and the survival rate was significantly different from day 30 until day 90; a consistently higher rate was observed in fish fed 800 mg/kg. The highest viscerosomatic index and intraperitoneal fat were observed in the group fed 500 mg/kg (p?<?0.05). The hepatosomatic index was significantly increased alongside increasing levels of E. hirta extract. The total white blood cell count in the control group was significantly higher on day 30, but on day 90 all the treatment groups showed higher levels. Hematocrit percentage was significantly different on days 30 and 90. Lymphocyte, eosinophil and thrombocyte levels were shown to be significantly different (p?<?0.05) when different groups of fish were compared. In conclusion, 300 mg/kg of E. hirta leaf extract could improve growth performance, hematological and some organosomatic indices in hybrid catfish.     

Dietary ascorbic acid influences the intestinal morphology and hematology of hybrid sorubim catfish (<Emphasis Type="Italic">Pseudoplatystoma reticulatum</Emphasis> × <Emphasis Type="Italic">P. corruscans</Emphasis>)

This study evaluated the effect of graded levels of dietary ascorbic acid (AA) (12.47, 20.27, 115.44, 475.50, 737.72, and 850.70 mg kg^?1) on growth, hematology, intestinal morphometry, and phagocyte activity of hybrid sorubim Pseudoplatystoma reticulatum × Pseudoplatystoma corruscans. Fish (n = 420, 14.57 ± 2.71 g, 15.11 ± 0.90 cm) were distributed in 30 polyethylene tanks (80 l) (5 replicates per treatment with 14 fish per tank) and fed for 45 days. Dietary treatment did not have a significant effect on growth metrics (P > 0.05). Fish fed 737.72 mg AA kg^?1 had a higher villi height (289.80 ± 19.96 μm) (P < 0.05) than fish fed 850.70 mg AA kg^?1 (245.4 ± 18.25 μm). Hemoglobin in fish fed 850.70 mg AA kg^?1 (5.34 ± 0.96 g dl^?1) was higher (P < 0.05) than fish fed 12.47 mg AA kg^?1 (3.42 ± 0.55 g dl^?1) and 20.27 mg AA kg^?1 (3.06 ± 1.26 g dl^?1). The erythrocyte number of hybrid sorubim fed 115.40 mg AA kg^?1 (1.73 ± 0.27 × 10⁶ μl^?1) and 475.50 mg AA kg^?1 (1.70 ± 0.28 × 10⁶ μl^?1) were higher (P < 0.05) than in those fed diets containing 20.27 mg AA kg^?1 (1.11 ± 0.34 × 10⁶ μl^?1). There was no significant effect (P > 0.05) of dietary AA on leukocyte and thrombocyte and on phagocyte activity and phagocyte index. Inclusion of AA in feed seems to increase the integrity of the intestinal mucosa and stimulate erythropoiesis in hybrid sorubim catfish.     

Determination of poly-β-hydroxybutyrate production by <Emphasis Type="Italic">Bacillus</Emphasis> spp. isolated from the intestines of various fishes

In this study, 30 strains of the genus Bacillus were isolated from various fresh fishes obtained from fish markets in Ankara, Turkey. They were identified as Bacillus pasteurii, Bacillus badius, Bacillus circulans, Bacillus licheniformis, Bacillus megaterium, Bacillus thuringiensis, Bacillus brevis, Bacillus cereus, Bacillus sphaericus, Bacillus subtilis, Bacillus coagulans, Bacillus lentus, and Bacillus pumilus. When poly-β-hydroxybutyrate (PHB) production by these strains was determined by spectrophotometry, it was found that PHB production ranged from 0.81–23.38% (w/v). PHB production and productivity were highest for B. pasteurii P2 (20.58% w/v) and B. lentus P18 (23.38% w/v). Furthermore, B. pasteurii P2 and B. lentus P18 were examined for PHB production using different carbon and nitrogen sources and in combined medium containing both carbon and nitrogen sources. The amounts of PHB produced by the strains in these media were more different than the amounts of PHB produced in nutrient broth medium.     

Metabolic adaptations of oxidative muscle during spawning migration in the Atlantic salmon <Emphasis Type="Italic">Salmo salar</Emphasis> L.

The adaptability/plasticity of the highly oxidative red muscle in Atlantic salmon was demonstrated during spawning migration. Substrate concentrations and the enzymatic pathways of ATP production were examined in red muscle obtained from Atlantic salmon at different sites along their migratory route in the Exploits River, Newfoundland, Canada. Individuals were chronologically sampled from a seawater site, two sites upstream, and at spawning. The 20% decrease in salmon body weight during the later stages of migration was accompanied by large decreases (mg dry weight⁻¹) in both glycogen (P < 0.01) and total muscle lipid (P < 0.01). In contrast, water content and protein concentration (mg dry weight⁻¹) of the red muscle increased by 25 and 34%, respectively, at spawning. Enzymes of the glycolytic pathways demonstrated a significant (P < 0.001) decrease in maximal activity as migration proceeded whereas enzymes of the oxidative phosphorylation pathways, specifically the citric acid cycle enzymes, exhibited an increase (P < 0.001) in maximal activity at spawning. The antioxidant enzyme superoxide dismutase also demonstrated an increase (P < 0.001) in maximal activity during the latter stages of migration. These adaptations imply that the red epaxial muscle of Atlantic salmon has a more efficient means of oxidizing lipids, while minimizing free radical damage, during the later stages of migration and spawning, thereby potentially increasing post spawning survival.     

Effect of starvation on activities and mRNA expression of lipoprotein lipase and hormone-sensitive lipase in tilapia (<Emphasis Type="Italic">Oreochromis niloticus</Emphasis> × <Emphasis Type="Italic">O. areus</Emphasis>)

A 4-week study was conducted to determine the effect of starvation on activities and mRNA expression of lipoprotein lipase (LPL) and hormone-sensitive lipase (HSL) in hybrid tilapia (Oreochromis niloticus × O. areus). The tissue samples were sampled once a week. Results showed that body weight (BW) and hepatosomatic index (HSI) were decreased significantly (P < 0.05) during starvation. The percentages of crude fat and crude protein in the whole body and the fat content in muscle decreased significantly (P < 0.05), while the rate of moisture and crude ash increased significantly (P < 0.05). The response of LPL, HSL activities and mRNA expression in tissues was tissue dependent. The activities of LPL and HSL in muscle at day 7 were elevated by 2.5 times (P < 0.05) and 11.8 times (P < 0.05) of the value at day 0, respectively, and both then decreased to pre-starvation levels at day 14 and finally stabilized at a certain level afterward. LPL and HSL mRNA abundance in muscle remained relatively stable between 0 and 14 day; then, a significant increase was seen after 14 days. In the liver, LPL activity maintained a significantly increasing trend during starvation, while HSL activity rose dramatically at day 7 of starvation by 2.35 times (P < 0.05) and finally stabilized at a certain level. The mRNA abundance of liver LPL increased significantly during the whole process of starvation (P < 0.05), whereas the mRNA abundance of liver HSL decreased significantly at day 7 of starvation, elevating significantly afterward (P < 0.05).     

松江鲈白介素15(TfIL-15)的结构特征与重组表达

为研究白介素15(Interleukin-15, IL-15)在松江鲈(Trachidermus fasciatus Heckel)先天免疫中的功能,本研究利用RACE技术克隆得到松江鲈IL-15基因(命名为TfIL-15)的全长cDNA序列,其长度为1140 bp,包括5¢-非编码区(5¢-UTR) 165 bp、开放阅读框(ORF) 522 bp和3¢UTR 453 bp。在5¢UTR区域,存在4个读码框外的AUG翻译起始位点。基因ORF编码173个氨基酸(aa),其中,前59 aa为信号肽序列。成熟肽全长为114 aa,预测分子量为12.975 kDa,理论等电点为5.15。同源比对发现,鱼类IL-15变异程度较高,TfIL-15与其他鱼类IL-15同源性在23%~61%之间。多序列比对和三维结构构建结果显示,TfIL-15具有典型4个α螺旋二级结构,形成二硫键的4个半胱氨酸高度保守。qRT-PCR分析表明,TfIL-15广泛表达于松江鲈各组织中。腹腔注射脂多糖(Lipopolysaccharides, LPS)后,TfIL-15 mRNA在血液、皮肤、肝脏和脾脏中均上调表达。在皮肤和血液中,刺激后2 h表达量迅速上调至最高峰,分别为对照组的74倍和41倍。脾脏和肝脏在刺激后12 h分别达到对照组的3倍和18倍。肝脏中,刺激后96 h,表达量再次上调至对照组的86倍。上述结果表明,TfIL-15可能参与了松江鲈抵抗外界刺激的先天免疫过程。另外,通过构建TfIL-15成熟肽的原核表达载体,成功获得重组蛋白,为进一步研究TfIL-15蛋白的功能奠定了基础。