首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 93 毫秒
1.
为证明日本鳗鲡(Anguilla japonica)生活史最后一步一产后鳗的命运,本研究模拟产后的日本鳗鲡继续在海水中养殖,观察其存活率及繁育情况.结果表明,产后鳗在海水中停食约18 d后,体能得到恢复,部分亲鱼开始出现摄食,1个月左右全部恢复摄食,经244 d养殖,雌、雄鳗体质量增加,存活率达94.6%.随后,给产后鳗注射外源性促性腺激素(鲤鱼脑垂体匀浆CPE和人绒毛膜促性腺激素HCG)后激发其退化的性腺(卵巢和精巢)重新发育(与当年银鳗作对照).通过性腺组织切片观察产后鳗和对照鳗性腺发育成熟的全过程及其差异,发现产后鳗起初性腺发育比当年银鳗差,但经多次注射激素后,产后鳗性腺成熟与当年银鳗同步,证明产后鳗生殖细胞对激素的敏感件高.应用17α,20β-双羟孕酮和促性腺激素释放激素类似物(GnRH-A3)使催熟的产后鳗和对照鳗均产卵和排精,并孵化出仔鱼,从而有力地证明,鳗鲡产后虽体质弱,但待体能恢复后能够继续生存和繁殖.本研究旨在探讨利用产后鳗作为今后鳗鲡人工繁殖亲鳗的可行性.  相似文献   

2.
张利红 《水产学报》2001,25(2):107-111
探讨了间隔15d多次埋植雄烯二酮(4-androstene-3,17-dine,ADSD)或甲基睾酮(17α-methyl-testosterone,MT)诱导日本鳗鲡性腺发育过程中,血清睾酮(testosterone,T)和17β-雌二醇(17β-estradiol,17β-E2)含量的变化。在雌鳗中,埋植ADSD后血清T和17β-E2含量显著升高,随后缓慢下降;埋植后第15d的血清T含量随埋植次数的增加呈下降趋势,而血清17β-E2含量随埋植次数的增加而逐渐增加。埋植MT则使雌鳗血清中T含量显著降低,而雌鳗血清17β-E2含量在埋植MT2次后显著升高。在雄鳗中,埋植ADSD后第15天的血清T和17β-E2水平均显著升高,并随埋植次数的增加而增加;而埋植MT后第15天的血清T含量也显著升高,并随埋植次数的增加而增加,但血清17β-E2水平仅在埋植第3次后显著高于对照组。研究结果表明:埋植ADSD和MT对日本鳗鲡血清T和17β-E2的影响存在明显的性别差异。  相似文献   

3.
为研究日本鳗鲡(Anguilla japonica)黑仔鳗饲料中发酵豆粕对鱼粉的替代效果及豆粕的可能作用,设置5组实验饲料:以含有60%鱼粉和5%豆粕的T0组为对照组,分别使用10%(T10组)和20%(T20组)的发酵豆粕替代对照组中鱼粉的11.6%和23.3%,并在此基础上再分别用4.5%的发酵豆粕替代T10组和T20组中全部的豆粕设置成T14.5组和T24.5组。在水泥池的网箱中饲养初始体质量为(0.405±0.003) g的日本鳗鲡黑仔鳗76 d。结果显示:5%豆粕含量不变的条件下,随着发酵豆粕使用量的增加,特定生长率、增重率和存活率逐渐升高;发酵豆粕替代豆粕后,T10组特定生长率、增重率和存活率显著高于T14.5组(P<0.05),T20组特定生长率、增重率和存活率高于T24.5组但差异不显著(P>0.05)。随着发酵豆粕使用量的增加,日本鳗鲡黑仔鳗肌肉的粗蛋白含量呈现先减少后增加的趋势,粗脂肪则相反。试验组血清中谷丙转氨酶(ALT)和谷草转氨酶(AST)活性以及丙二醛(MDA)含量均低于对照组,总抗氧化能力(T-AOC)活性除T14.5组外均显著高于对照组;T10组MDA含量显著低于T14.5组。随着发酵豆粕使用量的增加,肝脏中的T-AOC、总超氧化物歧化酶(T-SOD)和过氧化氢酶(CAT)活性呈现逐渐上升的趋势,MDA含量则相反,ALT、AST活性呈先上升后下降的趋势。血清总蛋白(TP)、白蛋白(ALB)和球蛋白(GLB)含量随发酵豆粕用量增加而增加;在鱼粉用量相同时,含有5%豆粕比不含豆粕的试验组有更高的血清TP以及GLB含量。以上结果表明:饲料中用发酵豆粕替代鱼粉可以提高日本鳗鲡黑仔鳗的生长性能、血清和肝脏抗氧化能力及肝功能,且最佳用量为20%;豆粕影响发酵豆粕对鱼粉的替代效果,含5%的豆粕比不含豆粕有更好的替代效果,但效果因发酵豆粕用量而异。  相似文献   

4.
日本鳗鲡早期幼苗趋光性及视觉发育特征   总被引:1,自引:0,他引:1  
研究了出膜后第1~9 d的日本鳗鲡(Anguilla japonica)早期幼苗,在不同光强度下趋光性分布及视觉发育组织学特征。结果显示:在8900 lux的强光条件下,日本鳗鲡早期幼苗随着发育,表现出明显的负趋光性。到9 d时,占存活幼苗52.2%的幼苗都集中在最暗的110 lux区域;而在2300 lux的弱光条件下,表现出趋弱光性。到9 d时,占存活幼苗44.6%的幼苗都集中在25 lux区域。视网膜发育的组织学观察发现,日本鳗鲡幼苗的视网膜发育首先出现的是外界膜和内界膜,最后出现的是外丛层。幼苗的整个视网膜结构到9 d时,发育为9亚层结构。视网膜中最发达的是外核层,由3种细胞构成。发育最快的是内核层,由2种细胞构成。结果表明,与日本鳗鲡早期幼苗趋光性有关的因素包括视网膜分层、视网膜厚度、内核层细胞数等多种因素。另外,本研究还探讨了日本鳗鲡幼苗在自然界可能生存的水深和光环境。  相似文献   

5.
用含HCG及鲤脑垂体(PG)匀浆液提取物(CPE)的W/O/W复乳,对塘养雌鳗进行注射催熟实验,雌鳗平均GSI达35.18%,最高达56.5%,其催熟效果较常规注射方法(平均GSI 27.9%,最高50.4%)好,用含LHRH-A,HCG,CPE的复乳和DOM生理盐水混悬剂对部分达到性成熟的鳗鲡进行催产,用W/O/W复乳诱导成熟的鳗鲡,排卵率为75%,用常规方法催熟的鳗鲡排卵率为55%,注射复乳制剂后,鳗鲡血清GtH含量可较长时间的保持较高水平,血清GtH的变化较常规注射方法缓和,注射乳剂还可使鳗鲡脑垂体GtH含量升高。  相似文献   

6.
牛磺酸对鲤生长及血清T_3、T_4含量的影响   总被引:6,自引:0,他引:6  
用牛磺酸作为饲料添加剂,以0.2%、0.4%、0.6%、0.8%的剂量将牛磺酸添加到基础饲料中,以基础饲料为对照,饲喂重(40.73±3.92)g的鲤60 d后,测定鱼体的相对增重率、饲料系数、血清中三碘甲状腺原氨酸(T3)及甲状腺素(T4)的含量,结果表明:牛磺酸显著地提高鲤的生长速度和血清甲状腺素的含量(P<0.05),极显著地提高鲤的血清三碘甲状腺原氨酸的含量(P<0.01),对饲料系数没有显著影响(P>0.05)。血清T3、T4含量的提高,是牛磺酸促进鱼体生长速度加快的重要原因之一。  相似文献   

7.
汪小东 《水产学报》2000,24(2):123-129
雄鳗注射5-6次、雌鳗注射9-10次鲤脑体匀浆液(CPE)+人绒毛膜促性腺激素(HCG)能分别诱导精巢和卵巢发育成熟。在雌雄鳗鲡,注射CPE+HCG可显著增加端脑、间脑、中脑和下丘脑mGnRH的含量,而对后脑和延髓mGnRH的影响较小;注射CPE+HCG增加雄鳗后脑和延髓cGnRH-Ⅱ含量,对雌鳗脑区cGnRH-Ⅱ则无显著影响。雌雄鳗鲡每次注射CPE+HCG后1天,血清促性腺激素(GtH)急剧上升  相似文献   

8.
日本鳗鲡人工催产后亲鱼恢复培养与再催产效果   总被引:3,自引:0,他引:3       下载免费PDF全文
日本鳗鲡(Anguillajaponica)产后亲鱼的恢复培养全过程包括:产后亲鱼的海水淡化、诱导开口以及亲鱼培育。对2种不同淡化方式的结果比较发现,日本鳗鲡亲鱼的海水淡化方式以缓慢连续的方式较好,即每天换水1次,每次淡化量为总盐度的3%~4%,总淡化时间为1个月。淡化后的亲鱼存活率分别为:自然产卵的产后亲鱼达到100%,人工授精的产后亲鱼为86.3%,而难产的产后亲鱼则为81.5%。在各种开口驯养方式中,以水蚯蚓为开口饵料的驯养效果较好。诱导亲鱼开始摄食所需时间最短,为18d;摄食量也最大,达到平均体重的2.5%。从水蚯蚓逐步转为全人工饵料后,进行日常亲鱼培育。经18个月的恢复培养后,使产后亲鱼的平均体重雌鳗330g、雄鳗150g分别恢复到765g和470g。但2次繁殖的各项指标中,催熟率、成熟系数和性腺发育情况远远低于野生鳗,而催产率和幼苗存活率则略高于野生鳗,其原因尚有待进一步研究。  相似文献   

9.
虽然许多水产科技人员都能培育出鳗纲幼体,然而能够排卵的鳗鲡雌体很少,即使获得了鱼卵、但受精率和孵化率都不高。这是因为大部分雌体在重复注射脑垂体激素卵黄发生后,实际上他们的卵母细胞并没有最后成熟,卵质老化。因此要获得高质量的鱼卵,必须研究诱导鳗卵最后成熟和排卵的技术。Yamanchi于1990年报道,17,20B一二羟基一4一朵自烷一3一酮(门,20gdihydroxy-4-pregnen-3-one,简称DHP),此种鲑鱼用的卵母细胞诱熟激素同样可以有效地诱导日本鳗缅卵母细胞最后成熟。为了获得优质鱼卵,了解鳗额注射DHP后的排卵和受精时间…  相似文献   

10.
目的研究自拟中药复方对兔血清中三碘甲状腺原氨酸(T3)、四碘甲状腺原氨酸(T4)、生长激素(HGH)含量的影响。方法将36只健康仔兔随机分为空白组、中药复方高、中、低剂量组4组,每组8只,饲喂30 d。中药复方高、中、低剂量组分别按照1.0%、2.0%、3.0%剂量添加到饲料中,空白组正常饲喂,试验结束时,采血分离血清,检测血清中T3、T4、HGH的含量。结果中药复方各组仔兔血清中HGH、T3、T4的含量均升高。结论该中药复方可通过提高血液中HGH、T3和T4的含量以促进仔兔的生长性能。  相似文献   

11.
12.
13.
A total of 180 fish (95.50 g) were fed with 0.1% levamisole, 0.5% thyme, and 0.5% echinacea crude extract for 60 days. The control group received no stimulant. The results of growth parameters indicated a significant positive effect of levamisole in comparison with the control group, though it was not significantly different from echinacea and thyme treatments (P > 0.05). No mortalities were observed in the treatments. Feed conversion ratio and protein efficiency ratio did not differ significantly between the treatments. The highest numbers of white and red blood cells and the greatest amounts of hemoglobin and hematocrit were detected in the levamisole treatment, showing significant differences with the other groups in the percentage of hemoglobin only (P < 0.05). The highest levels of MCH and MCHC were also measured in the levamisole treatment. Differential count of white blood cells revealed no significant differences in neutrophil and lymphocyte levels with the control. There was a significant increase in the percentage of eosinophil in the levamisole treatment alone. No significant differences were recorded in total protein, albumin, and aspartate aminotransferase and alanine aminotransferase enzymes. Levamisole treatment displayed the highest activities of glutathione peroxidase and lysozyme as well as the greatest amount of immunoglobulin. So 0.1 levamisole yielded better results in the growth, blood, and immunity parameters and can be used as a stimulant without injuring body organs.  相似文献   

14.
A cross‐sectional study was conducted from November 2017 to March 2018 at Lake Hawassa to determine the prevalence of larval Contracaecum infestation in Nile tilapia, (Oreochromis niloticus), African Catfish (Clarias gariepinus) and Barbus species (Barbus intermedius). Fifty‐two point six per cent (52.6%) previous prevalence and 5% precision were used to estimate the sample size. Accordingly, a total of 383 randomly sampled fish species comprising of 163 (42.6%) C. gariepinus, 159 (41.5%) O. niloticus and 61(15.9%) B. intermedius were examined. The length and weight of each sampled fish were recorded. All the sampled fish were examined for the evidence of Contracaecum parasites in Hawassa University Veterinary Parasitology and Pathology Laboratory. Chi‐square values and comparison of proportions were used to analyse the data. The overall prevalence of Contracaecum parasites of fish population was 31.6%. The distribution of parasite was significantly affected by fish species (p = .000), sexes (p = .018), length (p = .003) and weight classes of fish (p = .026). As a hygienic problem and gutting activity conducted at the sides of the Lake Hawassa and distribution of discarded fish wastes for surrounding piscivorous birds by butchers and other people, the life cycle of Contracaecum parasite was perpetuated. Thus, the parasite is of zoonotic significance. Therefore, awareness creation activities for societies and control of fish parasites should be conducted in the study area.  相似文献   

15.
16.
Abstract  Fecundity is an integral component of the calculation of Atlantic salmon, Salmo salar L., egg depositions in rivers. Fecundity determinations can be time consuming and prohibitively expensive in terms of application on a broad scale. Consequently, where river specific and annual data are not available, default means are used in calculations in Newfoundland and Labrador. It is important therefore to know the extent of variability among rivers, years and seasons and the potential error involved in using default values. Annual fecundity data were available for one river in Labrador and nine rivers in Newfoundland. Fecundity was determined from ovaries collected in the recreational fishery in the summer for all 10 rivers. For three of these rivers, fecundity determined from summer sampling was compared with that obtained from sampling at time of spawning in autumn. There was significant variability in fecundity with length as a covariate among rivers, years and seasons. Mean number of eggs per female decreased between 8.3% and 29.0% from summer to autumn while mean number of eggs per cm decreased from 5.0% to 28.5%. Depending on the measure of relative fecundity used (no. of eggs kg−1 or no. of eggs cm−1), results of simulations showed that estimates of egg deposition incorporating defaults can deviate from those obtained by applying year-specific and river-specific values by 50–75%, without adjusting for the seasonal reduction in fecundity, and by 30–50% with an adjustment. A sensitivity analysis revealed that of three parameters used in the calculation of egg deposition (size, percent female and fecundity), fecundity was the most influential.  相似文献   

17.
18.
中国综合水产养殖的发展历史、原理和分类   总被引:3,自引:1,他引:2  
董双林 《中国水产科学》2011,18(5):1202-1209
综合水产养殖是水产养殖的重要类型,它既包括同一水体内水生生物的混养,也包括水产养殖与同一水体或邻近区域进行的其他生产活动的结合。中国的稻田养鱼始于1 800年前,大规模的海水综合养殖始于公元1975年。目前中国开展的综合养殖模式有近百种,其依据的生态学原理主要有3个:通过养殖生物间的营养关系实现养殖废物的资源化利用;利用技术措施、养殖种类、养殖系统间功能互补或偏利作用平衡水质;养殖水体资源(时间、空间和饵料等)的充分利用。综合养殖系统可分为技术措施综合、养殖种类综合和系统综合三大类,其中系统综合类又可再分为水基系统综合和水基与陆基系统综合两个亚类。  相似文献   

19.
Abstract A portable multi‐point decoder system deployed in a tributary of the River Itchen, a southern English chalk stream, recorded the habitats used by PIT‐tagged juvenile salmon, Salmo salar L., trout, Salmo trutta L. and grayling, Thymallus thymallus L., with a high degree of spatial and temporal resolution. The fishes’ use of habitat was monitored at 350 locations throughout the stream during September/October 2001 (feeding period) and January/February 2002 (over‐wintering period). Salmon parr tended to occupy water 25–55 cm deep with a velocity between 0.4 and 1.0 m s?1. During both autumn and winter, first year salmon (0+ group) were associated with gravel substrate during the daytime and aquatic weed at night. In autumn, 1+ salmon were strongly associated with hard mud substrates during the day and with marginal tree roots at night. In winter, they were located on gravel substrate by day and gravel and mud at night. Trout were associated with a greater range of habitats than salmon, generally occupying deeper and faster water with increasing age. During the autumn, 0+ trout were located along shallow (5–10 cm) and slow (?0.1–0.4 m s?1) margins of the stream, amongst tree roots by day and on silty substrates at night. During winter the 0+ trout occupied silty substrates at all times. As age increased, trout increasingly used coarse substrates; hard mud, gravel and chalk, and weed at night. All age groups of grayling (0+, 1+ and 2+) tended to occupy hard gravel substrate at all times and used deeper and faster water with increasing age. The 1+ and 2+ groups were generally found in water 40–70 cm deep with a velocity between 0.3 and 0.5 ms?1, whilst the 0+ groups showed a preference for shallower water with reduced velocity at night, particularly in the winter. There were greater differences in the habitats used between species and age groups than between the autumn and winter periods, and the distribution of fish was more strongly influenced by substrate type than water depth or velocity. The results are discussed in relation to the habitat requirements of mixed salmonid populations and habitat management.  相似文献   

20.
ABSTRACT

Over 71% of the aquaculture production of Chile is based on salmonids, and given the recents problems in the world salmon industry, it is necessary to investigate the culture of new species as a vital priority to maintain an industry of great social and economic impact for Chile. Small-eye flounder, Paralichthys microps, and chilean flounder P. adspersus, are native, high-value flatfish present off the coasts of Perú and Chile, that are commonly exploted by artisanal fishermen. Since 1986 both species have been objects of research studies for culture based on techniques developed for Japanese flounder. This paper is a review of current knowledge of this species and to identify research needs for the near future. Natural spawning of small-eye flounder and chilean flounder broodstock in captivity is already possible, but the manipulation of spawning using photoperiod and hormonal inducement, as well as the role of broodstock nutrition in egg and larval quality, needs to be explored. Successful incubation and larval culture protocol for both species have been developed, with larval survival over 24% from certain egg batches. Nutritional characterization and requirements for chilean flounder eggs and larvae during the culture period, optimal temperature, density, light intensity and green-water culture, are all subjects of ongoing research. Efforts to improve early culture protocol continues with emphasis on causes of larval mortality, early use of dry feed, microbial ecology of culture tanks and water quality. Weaning from live to formulated diets has been investigated, demonstrating survival of 30-50%. Presently only about 1-5% of hatchery raised flounder show a pigment disorder. Research on formulated diets and the weaning process are under way to ameliorate these results. Juveniles are being grown experimental in tanks and net pens systems and their performance (growth, survival, health) in both systems is being evaluated. Chilean flounder require approximately 2.8 years to reach 1 kg. Effort is also focusing on improving juvenile growing protocol, including recirculation systems, culture environment and diet formulation. Much future research will be required to attain optimal production of the species, such as species-specific nutritional requirements, optimum stocking density, disease and health management and growing protocols with new systems (shallow raceway). At present there is enough known about chilean flounder to begin a pilot-stage that will be the key for future development of its culture.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号