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1.
白斑狗鱼雌性化诱导和雌雄同体现象 总被引：1，自引：0，他引：1
为研究和开发白斑狗鱼雌性化诱导方法,实验将750尾白斑狗鱼仔鱼随机分为5组,其中4组为实验组,分别从不同的发育时间(孵出后第10、20、30和40天)开始投喂用20 mg/L雌二醇浸泡过的水蚯蚓,另外1组为空白对照组,投喂正常水蚯蚓。各实验组喂饲17β-雌二醇30 d,然后将实验组和对照组的所有鱼进行正常饲养。至206 d将实验组和对照组的鱼进行成活情况统计,然后分别进行解剖,取出性腺进行组织学观察。结果显示,投喂用20 mg/L雌二醇浸泡过的水蚯蚓对白斑狗鱼仔鱼具有非常明显的致死效应,成活率由对照组的43.5%下降到14.3%±8.3%;30 d喂药组和40 d喂药组获得较高的雌雄比例,特别是30 d喂药组最高,达到了15∶7,由此推断白斑狗鱼性腺分化的关键时间点可能在孵出后的30~40 d;各实验组和对照组都出现很高比例的雌雄同体现象,即在同一性腺中同时出现了大量的初级卵母细胞(第Ⅱ时相)和精母细胞,而且这些卵母细胞有明显的退化现象,推测其性别分化过程中存在雌性先熟的幼体雌雄同体现象。本研究将为采用激素诱导手段生产白斑狗鱼全雌化苗种以及探讨白斑狗鱼性别决定和分化机制提供依据。 相似文献
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泥鳅的性腺分化及温度对性腺分化的影响 总被引：10，自引：0，他引：10
通过组织学方法观察泥鳅(Misgurnus anguillicaudatus)原始生殖细胞(PGCs)的迁移、生殖嵴的生成和性腺分化,并且研究了不同温度下性腺分化的差异。结果表明:1日龄仔鱼PGCs位于消化管上方的脏壁中胚层中;5日龄时PGCs迁移到背部的腹膜上皮上;10日龄时生殖嵴生成;20日龄时PGCs迁入生殖嵴,形成原始性腺;25日龄时原始性腺开始向卵巢分化;30日龄时原始性腺向精巢分化。46日龄时,双侧卵巢已经合并成1个卵巢。仔鱼孵化后的25~30 d为性腺分化的关键时期。在自然水温(23~25)℃和较低水温(22±1.0)℃中培育的幼鱼,雄性率分别为(51.1±1.5)%和(48.6±1.8)%,而培育于较高水温[(27±1.0)℃,(32±1.0)℃]中的泥鳅,雄性率分别达到了(82.0±3.4)%和(90.0±2.5)%,有些个体出现了雌雄同体的现象。研究表明,温度影响泥鳅的性腺分化,高温会诱导产生雄性。[中国水产科学,2007,14(1):74-82] 相似文献
4.
采用组织学和分子生物学方法,研究了投喂芳香化酶抑制剂来曲唑(LE)后暗纹东方鲀(Takifugu obscures)初孵仔鱼CYP19A、DMRT1基因表达以及性腺的组织学变化,以期进一步了解P450芳香化酶(P450arom)在鱼类早期性别分化过程中的作用。RT-PCR结果显示,对照组样品CYP19A和DMRT1表达显示性二态,雌性表达CYP19A基因,雄性表达DMRT1基因。LE处理组在性别分化期间,雄性样品单一表达DMRT1,雌性样品则同时表达CYP19A和DMRT1。qRT-PCR结果显示:LE处理组雌性仔鱼CYP19A基因表达被显著抑;虽然在仔鱼出膜后22d(dph)的表达水平高于9 dph,但仅为同日对照组的2.11%。LE处理组雌性样品22 dph时DMRT1基因表达量上调,至150 dph时达对照组雄性水平。55 dph的性腺组织学结果表明,LE处理可导致暗纹东方鲀稚鱼原始卵巢退化,并向功能性精巢发育。150 dph的LE处理组性腺均为精巢,并与对照组精巢发育同步。结论认为,暗纹东方鲀性腺分化期间P450arom是卵巢形成和维持发育所必须的,抑制P450arom活性可导致雌性暗纹东方鲀发生雄性化逆转。 相似文献
5.
施氏鲟的性腺分化及养殖水温对其性腺分化的影响 总被引：2，自引：1，他引：1
利用组织学方法观察了养殖施氏鲟(Acipenser schrenckii)原始生殖细胞(PGCs)的起源、迁移和原始生殖腺的形成及分化。结果表明,施氏鲟PGC最早出现于1.5 dph(days post-hatching)的仔鱼中肾管(又称吴尔夫氏管)原基一侧的中胚层中。3~7 dph,PGCs数目增多,并聚集成细胞索,17~31 dph,PGCs沿肠系膜向肾管区下方迁移,并与生殖嵴细胞一起形成原始性腺;40～60 dph时成群的小细胞团由肾区向原始性腺迁移,原始性腺上皮细胞柱状;90~120 dph,原始性腺中出现生殖上皮和性细胞,脂肪细胞和血管增多。180 dph以后,施氏鲟幼鱼性腺在组织学水平上出现光滑型(精巢)和褶皱型(卵巢)2种性腺组织结构,标志施氏鲟幼鱼性腺在解剖学水平上已经分化。本实验结果表明,孵化后31～180 d为其性腺分化的关键期。将孵化后56 d的仔鱼分别在不同的水温(27℃±0.5℃、24℃±0.5℃、21℃±0.5℃、18℃±0.5℃和15℃±0.5℃)中培育至210 d,组织学观察其性腺的发育和分化,结果发现,温度可影响施氏鲟幼鱼性腺分化的时间,但不影响其性腺分化的方向。高温(24℃和27℃)可使施氏鲟幼鱼提前性腺分化,其中27℃组较对照组(21℃)提前50 d,24℃组提前30 d;低温(15℃组)则延长幼鱼性腺分化的时间。施氏鲟幼鱼的性别分化不属于温度依赖型。 相似文献
6.
以杂交鲟(Huso huso ×Acipenser baeri )仔鱼为研究对象,将其分为 8个处理组,每组100尾(各设2个平行组),分别在孵化后6 d(对照组)、8 d、10 d、12 d、14 d、16 d和18 d开始投喂冰冻卤虫和碎水蚯蚓(以质量比1:1混合),5 d后只投喂碎水蚯蚓。第8组为饥饿组,从不投饵。水温17 ℃,实验周期30 d。结果显示,仔鱼于孵出后8日龄进入混合营养期;10日龄左右是仔鱼开始加速生长的关键时期;12日龄仔鱼进入外源性营养期。随起始投饵时间的延迟,仔鱼的全长、湿重、干重和粗蛋白含量下降,鱼体水分含量则随之升高。但对照组、8日龄及10日龄起始投喂组之间的鱼体水分、粗蛋白、粗脂肪含量并没有显著差异(P>0.05),14日龄及其以后各起始投喂组仔鱼的生长和鱼体生化成分则与上述各组存在显著差异(P相似文献
7.
利用组织学方法对人工培育的石鲽(Kareius bicoloratusBasiewsky)仔、幼鱼性腺发育进行研究。结果表明,性腺的发育与体长密切相关。刚孵化石鲽的原生殖细胞数目为2个,孵化3 d数目增至8个,之后经过迁移,至孵化9 d到达生殖嵴。在全长为7.2～8.5 mm(孵化9～11 d)的仔鱼中,性腺原基中的体细胞迅速增殖并包围原生殖细胞,后者在全长10～15 mm(孵化后10～35 d)的仔幼鱼中增殖成为生殖干细胞。原始性腺在全长15～30 mm(孵化40～60 d)的幼鱼中逐渐发育完善,呈细线状,位于腹腔后部中肾管下方紧贴体壁。雌性性腺最早在全长32.5 mm(孵化66 d)的个体中出现分化特征,至全长89～102 mm时雌性性腺特征完全分化。雄性性腺的分化较雌性性腺晚,最早在全长为91 mm的幼鱼中开始,至全长为114～118 mm时雄性性腺分化特征已经十分明显。 相似文献
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在水温(30±1)℃条件下对人工孵化的云斑尖塘鳢(Oxyeleotris marmorata)仔鱼进行转饵期不同投喂策略实验,对仔鱼生长和成活情况进行了研究,设计5个投喂组:轮虫投喂组(A组);70%轮虫+30%卤虫投喂组(B组);50%轮虫+50%卤虫投喂组(C组);30%轮虫+70%卤虫投喂组(D组);卤虫(幼虫)投喂组(E组)。结果显示:云斑尖塘鳢仔鱼对卤虫的摄食强度随卤虫在饵料中比例的升高而增大,其对混合饵料中轮虫和卤虫的摄食强度的比值(Ir/Ia)随食物组成的变化发生相应的变化。以轮虫-卤虫不同比例的混合饵料投喂时,D组仔鱼的增长率、增重率最高,可存活率不足50%,高于E组,显著低于其它各组;C组仔鱼生长指标略低于D组,但存活率为(74.00±2.29)%,综合指标显著好于其它各组。当混合饵料中轮虫和卤虫各占50%时,10日龄开始投喂组仔鱼的全长(13.07±0.13)mm,特定生长率(10.25±0.37)%/d,存活率(82.14±0.72)%,综合生长指标最好。结果表明,云斑尖塘鳢仔鱼转饵期进行联合投喂的最佳饵料比例为50%轮虫+50%卤虫,最佳转饵时间为10日龄。 相似文献
9.
长薄鳅开口饵料的研究 总被引：1，自引：0，他引：1
为寻找合适的长薄鳅仔鱼开口饵料,分别以卤虫、枝角类、蛋黄、卤虫+蛋黄、枝角类+蛋黄、卤虫+光合细菌、枝角类+光合细菌等7种不同的饵料对刚脱膜4d的仔鱼进行了饲喂试验.结果表明:(1)不同饵料对长薄鳅仔鱼的生长具有显著影响(P＜0.05),其中,枝角类+光合细菌组生长最快,绝对增重率和特定增重率分别为4.63±0.075 mg/d和19.02±0.404 ％/d;蛋黄组生长最慢,绝对增重率和特定增重率与其他各组差异显著(P＜0.05).(2)第1周投喂卤虫+光合细菌组合的饵料,仔鱼的成活率最高,为96％;蛋黄组的最终成活率最低,只有34％,且该组仔鱼个体发育较为缓慢,与其他各组差异显著(P＜0.05).根据试验结果,建议在水泥池育苗的条件下,对刚脱膜4d的长薄鳅仔鱼,第1周投喂卤虫+光合细菌,后期投喂枝角类+光合细菌,以提高仔鱼的成活率和成长率. 相似文献
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在人工育苗条件下,采用轮虫与牡蛎受精卵两种开口饵料,3种不同的投喂方式：开口单喂轮虫(A)、开口单喂牡蛎受精卵(B)、开口将牡蛎受精卵和轮虫混合投喂(C),分析对比不同饵料对仔鱼开口效果。通过观察5日龄仔鱼日摄食与4~20日龄仔鱼消化道饱满度的变化,探讨仔鱼摄食习性及光照与摄食的关系。结果发现,七带石斑鱼孵化开口后,投喂3d牡蛎受精卵者比直接投喂轮虫对仔鱼生长有明显的效果;10日龄前,B组在全长、肛前距、口裂宽方面都大于A、C两组,B组全长的特定生长率为4.969%,分别是A、C两组的2.5与2.4倍,生长速度最快;5日龄仔鱼在09∶00~10∶00与13∶00~14∶00时间段,有两个明显的摄食高峰期,光照强度分别为720~1 018 lx与865~923 lx;4日龄仔鱼其饱食率较低,只有40%达到了3级摄食量,4~10日龄的仔鱼饱食率波动幅度较大,10日龄后开始逐渐上升,13日龄后基本可以达到100%。 相似文献
11.
YASUHIRO FUJIOKA 《Fisheries Science》2002,68(4):889-893
ABSTRACT: Functional sex reversal of all-female nigorobuna Carassius carassius grandoculis to phenotypic males was examined by immersion exposure of fry to 17-methyltestosterone (17-MT) and controlled water temperature during early development. Fry were reared in water containing different concentrations of 17-MT at 24 and 30°C for 80 days starting 20 days after hatching. Although the fish exposed to 0.1 and 1.0 μg/L 17-MT at 24°C were all male, treatment with 10.0 μg/L 17-MT resulted in 43% females. Twenty-two percent males appeared in the control treatment at 30°C but the control at 24°C was entirely female. The proportion of males in treatments exposed to 0.01– 1.0 μg/L 17-MT at 30°C was slightly lower than in the respective treatments at 24°C. These results indicate that the phenotypic expression of sex in nigorobuna is thermolabile and that sex determination is under the control of genetic factors and temperature. Also, control of temperature during early development has been shown to be important for the production of all-female offspring for use as breeding stock for pond culture of fish suitable for preparation as 'funazushi'. 相似文献
12.
J. S. THOMPSON 《Journal of fish diseases》1982,5(1):1-11
Abstract. An epizootic of lymphoma in northern pike, Esox lucius L., occurring in the Åland Islands in Finnish waters of the Baltic Sea is described. Macroscopic inspection of 19 tumorous pike, 17 males and two females, as well as tissue observations by light and electron microscopy showed that this lymphoma is similar to those previously reported in esocid fishes from North America, Ireland and Sweden. Haematoxylin and eosin-stained light microscopic sections of tumour tissue suggested its classification as a lymphoblastic or stem cell lymphoma. Tumour cells cultured during several months at 4°C showed morphological features of differentiation and resembled plasma cells. No conclusive evidence of the presence of viruses in the lesion was obtained. 相似文献
13.
Awatef Trabelsi Jean‐Noël Gardeur Fabrice Teletchea Jean Brun‐Bellut Pascal Fontaine 《Aquaculture Research》2013,44(4):657-666
Based on the analysis of 11 morphometric variables of body (total length, body area and perimeter, myotome height and eye diameter) and yolk sac (length, height, area, perimeter and volume) of pike larvae, the aim of this study was to evaluate how larval size at hatching and growth of larvae hatched from single egg batches vary according to three hatching times: early, mid and late. Hatching time structures strongly pike larval morphometrics. Early hatched larvae have smaller body sizes at hatch, faster growth and higher yolk use efficiency than late hatched ones. Early hatched larvae seem to be premature and hatch at precocious developmental stage whereas late hatched individuals continue their growth within the egg shell and hatch at larger size but with lower reserves (yolk). A compensatory growth phase was observed for the early hatching pike larvae particularly during the first 5 days post hatch. Consequently, no significant difference in body parameters was recorded from day 10 post hatching whatever the hatching time. The higher growth accomplished by early hatched larvae may be related to a particular metabolic activity that converts more efficiently yolk into body tissues. 相似文献
14.
饥饿对白甲鱼(Onychostoma sima)仔鱼摄食、生长的影响 总被引：2，自引：0，他引：2
在实验室条件下,采用观察、测量记录外部形态特征等方法研究了饥饿胁迫下白甲鱼(Onychostoma sima)仔鱼的摄食、生长、形态和存活的变化。结果显示:在水温(20±1.5)℃时,饥饿组和投喂组白甲鱼仔鱼在孵化后第4天开始摄食,初次摄食率为48%,第6天初次摄食比率达到100%。饥饿组仔鱼抵达饥饿不可逆点(PNR)的时间为13.5 d,50%累计死亡率出现时间基本上与PNR出现时间相同(13.5 d),表明第13.5天为白甲鱼早期发育中较为敏感的阶段。试验期间,饥饿仔鱼体重、体长、眼间距和体高分别在第6、7、11和12天后均显著低于对照组(P<0.05)。试验结束(16 d)时饥饿组仔鱼体重、体长和眼径的瞬时增长率均显著低于摄食组(P<0.05),而头长、体高和眼间距差异不显著(P>0.05)。结果表明饥饿对仔鱼生长发育起延迟作用,混合营养期延迟投喂,仔鱼生长发育水平明显低于正常投喂仔鱼。 相似文献
15.
J. Engström-Öst M. Lehtiniemi S. H. Jónasdóttir M. Viitasalo 《Ecology of Freshwater Fish》2005,14(4):385-393
Abstract – We measured growth of pike larvae ( Esox lucius ) fed with freshwater and brackish-water zooplankton by monitoring larval wet weight during 18 days. The fish food was analysed for species composition, carbon, nitrogen and fatty acids. Further, we analysed fish larval faecal pellet production. Larval weight was significantly higher in fresh water than in brackish water with natural zooplankton as food. Growth, given as wet weight, showed a significant relationship with zooplankton (>100 μ m) food carbon and highly unsaturated fatty acids, 20:5ω3, 22:6ω3, ω6 fatty acids and the ω3/ω6 fatty acid ratio. Phytoplankton fatty acids (10–50 μ m), such as polyunsaturated fatty acids, 20:5ω3, 22:6ω3 and the ω3 fatty acids also correlated strongly with the wet weight of pike larvae. We demonstrated that several factors impact on pike larval growth. 相似文献
16.
Abstract. Oxytetracycline (OTC) was intraperitoneally injected into pike, Esox lucius L., to determine the validity of ages derived from cleithra and pelvic fin rays, to determine the rate of OTC incorporation into calcified structures, to decermine suitable marking dosages and to assess OTC-induced mortality.
The results showed that annuli were laid down on pike cleithra and pelvic fin rays. OTC was incorporated into most calcified structures as early as 6 h after injection and all structures were marked within 24 h. A dosage range of 25–50 mg OTC/kg fish was appropriate for marking pike. OTC-induced mortality was statistically insignificant. 相似文献
The results showed that annuli were laid down on pike cleithra and pelvic fin rays. OTC was incorporated into most calcified structures as early as 6 h after injection and all structures were marked within 24 h. A dosage range of 25–50 mg OTC/kg fish was appropriate for marking pike. OTC-induced mortality was statistically insignificant. 相似文献
17.
盐度对棘头梅童鱼胚胎发育和仔鱼存活的影响 总被引：1，自引：0，他引：1
观察比较了11个盐度梯度[0、5、10、15、20、25、30(自然海水)、35、40、45、50]下,棘头梅童鱼(Collichthys lueidus)胚胎的沉浮情况、孵化时间、孵化率和畸形率,并测定了初孵仔鱼的不投饵存活系数(SAI)。结果表明:(1)棘头梅童鱼胚胎在海水盐度为30及以上时100%漂浮;盐度为25时,95%漂浮,5%悬浮;盐度为20时95%悬浮,5%沉底;盐度为15时95%沉底,5%悬浮;盐度为10及以下时100%沉底。在水温18～20℃的条件下,棘头梅童鱼胚胎在盐度5～40范围内经28～32 h能孵化出仔鱼,盐度对孵化时间影响不显著(P>0.05)。但孵化率和畸形率因盐度不同而有显著差异。综合分析表明棘头梅童鱼胚胎孵化的适宜盐度范围为15～35,孵化最适盐度范围在20～30之间。(2)在可孵出鱼苗盐度范围(5～40)内,棘头梅童鱼仔鱼SAI值为(1.80±0.03)～(11.85±0.02),与卵的孵化率呈正相关关系。仔鱼生存的适宜生长盐度为10～30,最适盐度范围为20～25。 相似文献
18.
观察比较了8个盐度梯度[10、15、20、25、30(自然海水)、35、40和45]下七带石斑鱼Epinephelus septem fasciatus受精卵的孵化周期、孵化率和畸形率及卵黄囊仔鱼的畸形率,并在上述条件下对七带石斑鱼进行了耐饥饿试验,测定其生存活力指数(SAI).结果显示,受精卵孵化的最适盐度范围为30～35,盐度高于35,孵化率随着盐度的升高而降低,仔鱼畸形率随之升高;盐度低于25,孵化率随盐度的降低而降低,仔鱼畸形率随之升高.仔鱼的最适生存盐度为30～35,此盐度下的仔鱼存活系数为24.7±0.36和23.27土3.01. 相似文献
19.
《水生生物资源》2003,16(2):77-89
The histological development of the digestive tract in hatchery-reared green sturgeon (Acipenser medirostris) larvae and the effects of food deprivation on the digestive system organization were studied from hatching until 31 days post-hatching (dph). At hatching, the larval digestive system consisted of two rudiments: a large endodermal yolk sac and a primordial hind-gut. During the endogenous feeding phase, the wall of the yolk sac differentiated into the stomach (glandular and non-glandular regions) and the anterior and intermediate intestine, while the hind-gut primordium differentiated into the spiral valve and rectum. At the onset of exogenous feeding (15 dph at 16 °C), the organization and cytoarchitecture of the digestive system in green sturgeon larvae was generally similar to those of juveniles and adults. Larvae deprived of food exhibited a progressive deterioration, with subtle pathological changes observed after 5-d starvation: shrinkage of digestive epithelia, tissue degeneration, and necrosis were observed at 10–15 d of starvation (30 dph). No changes were observed in the mucous secretion of different regions of the digestive tract of food-deprived larvae. The histological analysis of the larval digestive system may be used to evaluate the nutritional condition of larval green sturgeon in their nursery habitats in spawning rivers, which are affected by dams and flow diversions. 相似文献
20.
饥饿对点带石斑鱼饵料转换期仔鱼生长和发育的影响 总被引：10，自引：3，他引：7
在盐度29、水温27.8~28.8℃的条件下,进行点带石斑鱼仔鱼饥饿实验,确定仔鱼初次摄食饥饿不可逆点(PNR);观察饥饿条件下点带石斑鱼饵料转换期(初孵仔鱼,5、8、10、15和20日龄)的存活与生长、油球利用、鳍棘生长和游泳行为的变化。结果表明:点带石斑鱼从初次摄食到PNR期仅2~3d,这个耐受饥饿的时间临界点发生在孵化后的第5天,即转入外源性营养的第3天。在饥饿条件下初孵仔鱼,5、8、10、15和20日龄仔鱼的全部死亡时间分别为7 d、3 d、4 d、3 d、4 d和6 d;半数死亡时间分别为5 d、1.5 d、2 d、1.5 d、2d和3.5d,说明5日龄和10日龄是点带石斑鱼早期发育中最为敏感的阶段。饥饿会延缓初孵仔鱼对油球的利用。随着饥饿时间的延长,仔鱼的生长与正常条件下仔鱼的生长差异显著(P<0.05)。饥饿仔鱼体长较短,头大且体瘦,长期饥饿后脑后部下陷;行为变化表现为表层集群游动觅食,游动缓慢,反应迟钝和静伏底。 相似文献