鲈鱼（Lateolabrax japonicas）受精卵及仔鱼对电解处理海水的适应性研究

本文研究了鲈鱼受精卵及仔鱼对纳米催化电解技术消毒处理海水中游离氯的适应性,结果表明随着电解处理当量的升高,水体中含氯量的提高,鲈鱼受精卵的孵化率有所降低;当电解处理当量控制在4．9 w·h/t以内时,海水与经爆气中和的无残余氯海水的孵化率相近;经过9．6 w·h/t电解当量处理,海水中的余氯含量约为1．3 mg/L,该浓度对鲈仔鱼成活率影响较大;在经硫代硫酸钠中和、排除电解余氯的海水中,鲈鱼苗可进行正常培育,育苗效果有显著提高。     

斜带石斑鱼牛磺酸转运蛋白基因的克隆及饲料牛磺酸含量对其表达的影响

牛磺酸转运蛋白(Taurine transporter,TauT)是牛磺酸跨膜转运的重要载体,在鱼类的生长、代谢及性成熟过程中发挥重要作用。本文采用RT-PCR和RACE技术,克隆体质量(12.85±0.46)g的斜带石斑鱼Epinephelus coioides TauT cDNA蛋白质编码区序列。结果表明:斜带石斑鱼TauT cDNA蛋白质编码区为1 881bp,编码626个氨基酸,分子量为70 126.80Da,与已克隆的其他鱼类的同源性很高,而与鸟类和哺乳动物的同源性较低。在水温(27±2)℃下,给斜带石斑鱼投喂含牛磺酸0%、0.5%、1%和1.5%的饲料28d后,用Realtime PCR法检测不同组织中TauT mRNA的相对表达量,结果表明:TauT mRNA在所测的各组织中均有表达,但肝脏、心脏、脑表达水平最高,肾脏、鳃、脾脏次之,肠道、肌肉、脂肪组织最低。牛磺酸添加组中组织TauT mRNA的表达量均高于对照组,1.0%和1.5%两组间差异不明显,但均高于0.5%组。饲料中添加牛磺酸能促进斜带石斑鱼组织中TauT mRNA的表达。     

三碘甲腺原氨酸对斜带石斑鱼卵黄囊期仔鱼消化道发育和存活的影响

运用放射免疫测定方法检测了斜带石斑鱼早期发育过程中三碘甲腺原氨酸（T3）的变化,并用T3处理卵黄囊期仔鱼,研究其对发育、生长和存活的影响。斜带石斑鱼受精卵中含有相当量的T3,T3随发育而逐渐下降,到仔鱼开口时已经检测不到,提示甲状腺激素可能被胚胎和卵黄囊仔鱼所利用而参与其发育进程。在孵化后24 h内,T3促进发育的作用不明显;在孵化24 h后,T3对仔鱼消化道的发育有促进作用。在孵化72 h后, 0.01 mg·L-1 T3处理组仔鱼直肠管径明显比对照大,而小肠管径和全长与对照相比差异均不明显;0.1 mg·L-1和1 mg·L-1 T3处理组仔鱼小肠和直肠管径显著比对照大,而全长显著比对照短。1 mg·L-1 T3显著加速了仔鱼卵黄囊的吸收,但对油球的吸收无影响。在孵化后第8天,0.01 mg·L-1 T3处理组仔鱼存活率明显比对照组高。结果表明,甲状腺激素促进卵黄囊期仔鱼消化道发育的作用与发育时期密切相关,孵化后24 h内,消化道对T3不敏感,此后则变得敏感; 0.01 mg·L-1 T3能提高仔鱼存活率。     

Improvement of the survival in the seven-band grouper Epinephelus septemfasciatus larvae by optimizing aeration and water inlet in the mass-scale rearing tank

The water flow in larval rearing tanks has been indicated to cause mass mortality of the seven-band grouper Epinephelus septemfasciatus larvae. Therefore, a new aerating method was tested in an actual scale intensive rearing tank (8.0 m in diameter, 1.87 m of water depth, 100 m³ of volume), in which an aerator was positioned at the center of the rearing tank surrounding cylindrical drain (1.2 m in diameter) to generate the flow field, and seven larval rearing trials were performed. The survival rate with the former aeration methods were compared, in which several aerators were located in the rearing tank. The survival rate at 10 days after hatching with the new aeration method (61.5±5.1%, n=7) was approximately three times higher than the former methods (21.2±13.7%, n=6). The flow environment of rearing tanks was also examined by quantifying the flow field, and the relationship between the flow field in the rearing tank, behavior of larvae and survival discussed. It was confirmed that the vertical circulating flow was observed in rearing tanks, and determined effectively the survival and the behavior of grouper larvae in patchiness.     

Precocious sex change and spermatogenesis in the underyearling Malabar grouper Epinephelus malabaricus by androgen treatment

The Malabar grouper Epinephelus malabaricus is an important candidate species for commercial aquaculture in tropical and subtropical areas. In nature, this species requires more than 10 years to change sex from female to male and have active spermatogenic tissues in the testis. Thus, it is essential to find a means of producing sperm for seed production. This is the first report of artificial sex change in underyearling E. malabaricus . Female E. malabaricus with immature ovaries at 144 days post-hatch (DPH) were fed a diet with 17α-methyltestosterone (MT) at 50 μg g⁻¹ diet for 6 months. Sex change occurred in most of the treated fish, which had testis with all stages of spermatogenic germ cells including spermatozoa. In contrast, most of the control fish had immature ovaries. These results, which reveal that germ cells in the underyearling grouper have the ability to produce spermatozoa in response to exogenous androgen, demonstrate that sex change can be artificially induced during ovarian development.     

Effect of temperature on survival,growth and malformation of cultured larvae and juveniles of the seven-band grouper Epinephelus septemfasciatus

The effects of rearing temperature (23–29 °C) during the larval and juvenile stage on survival, growth and skeletal malformations in the seven-band grouper Epinephelus septemfasciatus were investigated. The survival rate of juveniles 30–40 mm in total length emerging from eggs was higher at 25 and 26 °C (0.1–1.3 %) than at 23 °C or 27–29 °C (0.004–1.5 %). Growth (increase in total length) was accelerated at higher temperatures. The frequency of malformed individuals was lower at 25–27 °C (36.0–61.5 %) than at 23, 28 or 29 °C (65.3–76.9 %). Specific incidences of spinal curvature and centrum fusion or defects in juveniles were not related to rearing temperature. However, incidences of twisted or compressed vertebrae (6.5–64.0 %) were higher at higher temperatures, while the incidence of bifurcated neural spine was significantly higher at 23 °C (43.6–54.4 %) than at other temperatures (3.3–22.7 %). The incidence rate of spinal curvature (23.3 %) was significantly higher in juveniles with a deflated swim bladder, regardless of rearing temperature. The results of this study suggest that the optimum culture temperature for seven-band grouper is 25–26 °C, collectively considering the survival, growth and incidences of abnormalities. Our results also demonstrate the significance of identifying the conditions for swim bladder inflation to prevent spinal curvature in seven-band grouper.     

东吾洋中国对虾小规格仔虾种苗放流技术及其增殖效果

根据１９８６－１９９５年在东吾洋放流的９７９４８万尾中国对虾种苗资料。研究了仔虾种苗放流技术和增殖效果,结果表明,只要掌握好种苗放流技术,加强海区管理,直接放流未经中间暂养培育,平均体长在１０ｍｍ以上的仔虾种苗,年平均加捕率可达５．２６％,增殖效果十分显著。     

Effect of the culture system and culture technique on biochemical characteristics of Pavlova lutheri and its nutritional value for Crassostrea gigas larvae

Pavlova lutheri was cultivated in carboys using batch technique and in a flat alveolar photobioreactor (FAP), using initially batch and then semi‐continuous techniques. Growth and productivity of the cultures were compared and their nutritional quality was assessed by analysing their biochemical composition (gross composition, fatty acids and sterols) and by evaluating their food value for Pacific oyster (Crassostrea gigas) larvae as bispecific diet in association with Chaetoceros calcitrans forma pumilum. The highest productivity was achieved with the FAP operating in semi‐continuous mode. Gross composition of P. lutheri was similar in all cultures, while cellular organic matter content of the microalga grown in FAP in semi‐continuous mode was lower. Significant differences in fatty acid content were detected with respect to the n‐6 polyunsaturated fatty acid fraction, which was lower in cells cultivated in the FAP in semi‐continuous mode. As concerns the main individual fatty acids, docosahexaenoic acid (DHA) content was higher in cells cultivated in the photobioreactor in batch mode than in carboys. The neutral lipid fraction contained seven principal sterols and the comparison among the cultures evidenced different proportions and different patterns. No differences were observed among larvae fed diets containing P. lutheri grown in carboys or in the FAP.     

Effects of delayed first feeding on the survival and growth of tiger grouper,Epinephelus fuscoguttatus (Forsskål, 1775), larvae

The effects of delayed first feeding on the survival and growth of tiger grouper, Epinephelus fuscoguttatus (Forsskål 1775), larvae were examined under controlled conditions. The total length, yolk sac volume, oil globule volume, yolk sac absorption time and nutritional transition period (NTP) of the larvae fed at different first times (0, 6, 12, 18 and 24 h after the mouth opening stage; h AMO) were compared. Larval first feed intake was observed at 54 h after hatching (h AH) at 27.5 ± 0.5 °C. The yolk sac was consumed more rapidly with an increase in delayed first feeding and was significantly different among treatments (P<0.05). Larvae first fed at 0 h AMO had the longest yolk sac absorption (72 h AH) and NTP (20 h) times and had the highest survival and growth rates at the end of the experimental period (360 h AH), being significantly higher (P<0.05) than the other treatments. First mortality was observed at 69 h AH, approximately 2 h after point of no return (PNR) occurred. This study suggests that first feeding of tiger grouper larvae should commence at 0 h AMO for enhancement of larval survival and growth.     

微米纯氧气泡增氧技术养殖大菱鲆效果初探

试验旨在分析新型微米纯氧气泡增氧养殖大菱鲆的效果。试验采用微米纯氧气泡增氧和机械增氧2种方式,设置机械增氧组(溶解氧6~9 mg/L)、微米纯氧增氧Ⅰ组(溶解氧6~9 mg/L)和微米纯氧增氧Ⅱ组(溶解氧15~20 mg/L)3个试验组。结果表明,微米纯氧Ⅰ组大菱鲆的体重增长、成活率、肥满度及饵料转化率高于机械增氧组;微米纯氧Ⅱ组各指标低于机械增氧组。7个月的大规模生产试验(800 m2水面,溶解氧6~9 mg/L)表明,采用微米纯氧气泡增氧养殖大菱鲆,各测定指标均显著高于机械增氧,可以加快大菱鲆生长,提高成活率和饵料转化率。