孵化季节对阿根廷滑柔鱼生长发育的影响

头足类属种具有寿命短、终生一次繁殖产卵的生长发育特性,这些特性往往与仔鱼的孵化季节密切相关且影响世代的繁衍交替。为此,基于日龄判读和孵化月份推算,研究阿根廷滑柔鱼性腺成熟个体大小与孵化月份的效应关系,分析孵化月份对其生长发育的影响。结果显示,阿根廷滑柔鱼性腺成熟雌性个体的胴长为(246.59±40.36) mm,日龄为(293.79±32.68) d,平均生长速率为(0.84±0.11) mm/d;成熟雄性个体的胴长为(222.82±28.60) mm,日龄为(299.24±32.97) d,平均生长速率为(0.75±0.08) mm/d。性腺成熟个体的孵化月份为3—8月。随着孵化月份推移,性腺成熟个体的日龄显著降低,而平均生长速率逐渐增加;性腺成熟个体胴长大小与其平均生长速率密切相关;孵化月份对雌雄个体生长发育的影响效应具有一致性,较早孵化的个体生长速率较慢,而晚孵化的个体生长速率较快。研究表明,阿根廷滑柔鱼的生长发育与孵化季节密切相关,不同孵化月份的个体通过调节生长速率以达到性腺成熟胴长。     

尼罗罗非鱼仔鱼个体发育及性腺分化的发育

通过形态学、组织学的描述和显微结构的观察,研究了尼罗罗非鱼（Oreochromis niloticus）仔鱼在自然水温条件下（26～30℃）的个体发育和性腺分化发育过程。结果表明,仔鱼个体发育分为2个时期,仔鱼前期（从出膜到卵黄囊消失）和仔鱼后期（卵黄囊消失至奇鳍褶消失）;性腺发育分化的时序为：5DPH时,开始出现生殖嵴;10DPH时,出现少数原始生殖细胞,形成原始性腺;28DPH时,可清晰辨认卵原细胞,呈现明显的性腺分化组织学特征,至42DPH时可辨认精原细胞。     

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。     

瘦素在生殖调节方面的研究进展

瘦素是一种由Leptin(ob)基因编码并主要由脂肪组织合成分泌的蛋白质类激素，广泛存在于各组织、器官中。其在调节机体脂肪和保持体重方面具有重要作用。对它的最初的研究主要集中在肥胖的作用，但以后的研究结果发现其缺乏不是造成单纯肥胖的原因。有研究表明，瘦素亦可作为一种代谢信号对下丘脑－垂体－性腺轴发挥功能。     

Reproductive cycle of the south American scallop Amusium laurenti (Gmelin, 1791) (Bivalvia, Pectinidae)

Amusium laurenti is a functional hermaphroditewith well differentiated male and female gonadalareas. The gonadal index varies throughout the yearwith maximum values occurring in January, March andJuly, and minimum ones in August and September. Partial spawning (with respect to the individual andthe population) occurred from January to February andMarch to May. The major spawning event coincided withthe end of the period during which bottom watertemperature increased to temperatures above 26°C(July–August). Subsequently temperature decreased to22°C, with a period of gonadal restoration andincreasing gonadal index. Histological analysis ofthe gonads correlated with the gonadal index.     

6种石斑鱼成鱼的性腺发育、脑垂体结构以及垂体中FSHβ和LHβ细胞的免疫识别

以日本海域捕获的宝石石斑鱼(Epinephelus areolatus)、黑边石斑鱼(E.fasciatus)、赤点石斑鱼(E.akaara)、尾纹九棘鲈(Cephalopholis urodeta)、蜂巢石斑鱼(E.merra)和纹波石斑鱼(E.ongus)成鱼为对象,比较其性腺发育和脑垂体结构以及垂体中FSHβ和LHβ免疫信号的分布。结果表明:宝石石斑鱼、黑边石斑鱼、赤点石斑鱼和尾纹九棘鲈性腺发育为未成熟阶段,蜂巢石斑鱼和纹波石斑鱼性腺发育为成熟阶段。6种石斑鱼的脑垂体位于间脑腹面,由神经垂体(NH)和腺垂体(AH)组成。腺垂体从左至右进一步细分为前外侧部(RPD)、中外侧部(PPD)和中间部(PI)。在宝石石斑鱼、赤点石斑鱼和纹波石斑鱼中NH结构被PPD隔开分为上下两部分,而在黑边石斑鱼、尾纹九棘鲈和蜂巢石斑鱼中NH为一个整体。6种石斑鱼脑垂体中FSHβ和LHβ细胞的免疫信号主要分布在PPD和PI区域,且FSHβ信号强度均较LHβ强,推断在石斑鱼性腺发育成熟前后,FSHβ较LHβ重要。为石斑鱼的资源保护及人工繁殖方面提供基础生物学资料和理论依据。     

人工诱导青田田鱼雌核发育子代形态和遗传分析

浙江青田稻鱼共生系统为全球重要农业文化遗产之一,田鱼是共生系统的一个重要元素。为了开发田鱼优良种质资源,本研究采用紫外线灭活精子、染色体加倍等雌核发育技术,成功获得雌核发育子一代（G1）。对照普通子一代（F1）,测量和观察了160日龄G1的形态特征和性腺发育情况;在全基因组水平上,利用SNP技术,鉴定和分析了G1遗传物质。结果发现G1有3种体色,个体间生长差异大,黑色生长最快,平均体质量达392.45 g。G1平均生长速度慢于F1。G1形态参数与F1存在差异,全长与体高之比差异极显著。G1个体之间卵巢发育不一致,大个体的卵巢发育类似于F1,主要为Ⅲ时相的初级卵母细胞。SNP检测发现,通过1次雌核发育技术的种质改良,田鱼遗传物质的纯合性由母本平均38.42%提高到G1平均61.85%,并有父本遗传物质渗入G1个体,致使个体在体色和生长速度方面均表现出显著的差异性。本研究成功得到了青田田鱼人工雌核发育群体,为今后青田田鱼育种和种质资源开发奠定了良好基础。     

水泥池养殖香鱼性腺发育的观察

对水泥池养殖的香鱼卵巢、精巢发育做组织学观察,并与洄游型、陆封型香鱼的性腺发育做比较:养殖香鱼卵母细胞的结构和洄游型香鱼、陆封型香鱼基本一致;受精孔和精孔细胞出现的时间早于洄游型香鱼和陆封型香鱼。养殖香鱼卵巢发育略早于野生香鱼,但发育速度比野生香鱼慢,尤其慢于陆封香鱼。精巢结构属叶型壶腹型结构。雄鱼发育成熟早于雌鱼,能自然排精。雌鱼不用激素诱导即可获得游离卵。     

Assessment of sex and evaluation of ovarian maturation of fish using ultrasonography

Ultrasonography is a non‐invasive method that can be used to assess sex and maturity of fish. This study was conducted to examine the feasibility of using ultrasound images to sex juvenile and mature halibut Hippoglossus hippoglossus (Linnaeus), mature winter Pleuronectes americanus (Walbaum) and yellowtail flounder Pleuronectes ferruginea (Storer) and mature haddock Melanogrammus aeglefinus (Linnaeus). In females, both immature and mature ovaries were relatively easy to distinguish, but in males only mature testes were consistently distinguishable. Ovarian maturation of haddock and ovulatory cycles of halibut may also be assessed using ultrasound.     

Partial or total replacement of fish meal byplant protein affects gonadal development and plasma17 β-estradiol levels in female Nile tilapia

This study was conducted to evaluate theeffect of plant proteinbased diets on gonadaldevelopment and plasma 17 -estradiol (E2) levelin female Nile tilapia Oreochromis niloticus.Fish with a mean body weight of 6.7 (0.1) g were fedfour different diets with the same digestible protein(DP) and digestible energy (DE) containing gradedlevels of a mixture of plant ingredients as partial ortotal replacement of fish meal protein for 20 weeks.The control diet (D0) was based on fish meal, twodiets containing 33% (D33) and 66% (D66) of plantprotein, and one diet containing only plant protein(D100). Fish were sampled at 12 and 20 weeks. Nosignificant differences were found in different stagesof oocyte development and plasma E2 levels betweentilapia fed diets D0 and D100 at 12 weeks. Eight weekslater tilapia fed diet D0 showed a higher (P < 0.05)level of E2 than the D100 group. This difference andthe reduced proportion of vitellogenic and matureoocytes demonstrated that diets containing only plantprotein are less efficient in terms of tilapia growthand consequently ovarian development.