Factors affecting the reproductive efficiency in crayfish: implications for aquaculture

In recent years, crayfish aquaculture industry has been developing rapidly in different regions of the world. Crayfish aquaculture is often carried out in dams, lakes and extensive pond systems. There is an increasing demand for crayfish juvenile in aquaculture sector. Therefore, it is important to know which factors affect reproductive efficiency in crayfish. In the present review, factors affecting the reproductive efficiency of crayfish are divided into two main sections, external and internal factors. Dietary lipids, phospholipids, highly unsaturated fatty acids, protein and amino acids, vitamins and carotenoids are important external factors affecting broodstock crayfish reproduction. In addition, various external (i.e. female size, stocking density, temperature, photoperiod, sex ratio) and internal (i.e. endogenous hormones) factors affect the reproductive efficiency in crayfish. This study reviews the present knowledge with the purpose of realizing the factors that are important to reach optimal crayfish nutrition, maturation and reproduction (i.e. pleopodal egg number and quality). This review will particularly be useful for crayfish farmers and crayfish hatchery units.     

橄榄蛏蚌性腺发育与生长

2008年8月—2009年10月,每月采集一批橄榄蛏蚌,分别进行可量性状的测定和年龄鉴定,并研究了其肥满度周年变化规律。为了揭示其繁殖特性,取繁殖季节性腺制作石蜡切片,经苏木精和伊红染色后在显微镜下观察其形态结构,并测量性腺细胞的直径。结果表明,橄榄蛏蚌的肥满度在每年的5月出现最高峰,且一年只有一个高峰,因而橄榄蛏蚌繁殖为一年产卵一次、繁殖一次。橄榄蛏蚌性腺细胞直径为49.3～70.2μm。随着水温的升高,橄榄蛏蚌的摄食活性增强。统计学数据分析表明,橄榄蛏蚌体质量与壳长、壳宽和壳高均呈指数关系,而后三者之间呈线性关系。对体质量影响最大的指标是壳高,最小的指标为壳长。     

日本对虾越冬亲虾性腺促熟及工厂化育苗技术研究

1997、1998年利用越冬亲虾进行性腺促熟,用镊烫法切除眼柄,促进亲虾发育。结果:两年共培育亲虾雌虾8204尾。雄虾5683尾,获交尾虾5360尾。交尾率为71.81％。每年两批育苗,共利用水体1720m~3,育出0.7～1.1cm的虾苗12450万尾,平均单位水体出苗量为7.24万尾/m~3,效益显著。     

人工诱导日本鳗鲡成熟过程中血清及性腺内类固醇激素含量的变化

为分析日本鳗鲡(Anguilla japonica)经过多次注射鲤鱼脑垂体和人绒毛膜促性腺激素后,血清及性腺组织中性类固醇激素的含量及变化,采用超高效液相色谱-串联质谱联用(UPLC-MS/MS)对血清内6种类固醇激素[睾酮(Testosterone,T)、17α-羟基孕酮(17α-hydroxyprogesterone,17α-OHP)、17α,20β-二羟基-4-孕烯-3-酮(17α,20β-dihydroxy-4-pregnen-3-one,DHP)、雌酮(estrone,E_1)、雌二醇(estradiol-17β,E_2)、雌三醇(estriol,E_3)]以及性腺中4种类固醇激素(T、DHP、E_2、E_3)进行研究。结果表明,血清及性腺组织样品平均回收率分别为86.9%~98%、75.6%~88.1%;方法检出限(S/N10)分别为0.1 ng/g、0.1 ng/m L。对样品进行测定,结果表明,随着日本鳗鲡性腺发育,实验组日本鳗鲡血清及性腺中类固醇激素的含量呈逐步增加的趋势,其中,实验组日本鳗鲡血清中除E_3(难产时含量最高)外,其他5种类固醇激素均在产卵时含量最高;实验组日本鳗鲡性腺内E_2及DHP在难产时含量最高。对照组日本鳗鲡血清内E_1、E_3以及性腺内E_2、E_3在整个实验周期均未检测到。应用本方法对日本鳗鲡血清及性腺内类固醇激素进行定量分析,具有灵敏、高回收率、准确、稳定等特点,研究结果不仅对日本鳗鲡性腺发育过程中性类固醇激素的研究有了初步的认识,更对其他硬骨鱼类性腺发育过程中体内激素变化的研究具有重要参考意义。     

黄鳝组织脂肪含量变动规律研究

采用氯仿甲醇法(V氯仿∶V甲醇=2∶1)提取黄鳝肌肉、肝脏和性腺总脂,研究结果显示黄鳝肌肉、肝脏和卵巢组织脂肪周年变动范围分别为1.12%~1.61%、2.76%~4.16%和1.94%~6.57%。黄鳝肌肉脂肪含量秋冬季较高,而春夏季较低;肝脏脂肪含量在夏、秋二季高,越冬期基本没消耗;卵巢脂肪含量夏季显著高于其它季节。相同季节中,黄鳝肌肉中脂肪含量个体较大的较高,特别是在冬季更为明显;肝脏中的脂肪含量受黄鳝个体大小的影响不显著;而卵巢脂肪含量在春、夏季节,个体越大含量越高,而秋、冬季节差异不显著。肌肉组织是黄鳝脂肪的主要贮存组织,肌肉脂肪越冬期消耗大,卵巢发育期肌肉脂肪含量与卵巢脂肪含量呈负相关,肌肉贮存的脂肪有转移到卵巢的现象。肝脏不是黄鳝脂肪的主要贮存组织,脂肪含量高低主要与个体生理活动强度大小相关。春季到夏季雌黄鳝摄取的营养主要保证卵巢发育,夏季到秋季黄鳝摄取的能量部分贮存于肌肉组织中。黄鳝组织中的脂肪含量与生长、繁殖和越冬等密切相关。     

Estimates of heritabilities and genetic correlations for growth and gonad traits in the sea urchin Strongylocentrotus intermedius

The present study is the first estimate for the sea urchin, Strongylocentrotus intermedius, of genetic parameters for growth and gonad traits during the entire reproductive period. 2165–5764 sea urchins were sampled from 74 to 120 families at six different growth stages. Six hundred individuals were sampled from 20 randomly chosen families at harvest. Coefficients of variation for most growth and gonad traits were high (18.08–78.66%) suggesting a good variation foundation for breeding. Point estimate for heritabilities based on the sire components of variance were moderate to high for test height (0.24–0.39), test diameter (0.21–0.48) and body weight (0.16–0.49). Heritabilities of gonad wet weight, gonad index and gonad moisture at harvest were 0.17, 0.41 and 0.50 respectively (moderate or high). Gonad colour parameters, L^* (lightness) and a^* (redness) have a heritability of 0, while b^* (yellowness) and colour difference ΔE₁ and ΔE₂ have very similar heritabilities of 0.2, 0.18 and 0.21 respectively. Heritabilities of β‐carotene concentration and content were 0.89 and 0.44 respectively. The genetic correlations between the two measured traits ranged from ?0.984 to 0.999. Gonad wet weight, L^*, b^*, β‐carotene concentration and β‐carotene content had significant positive genetic correlations with all the growth traits. However, gonad index, gonad moisture and colour differences ΔE₁ and ΔE₂ had significant negative genetic correlations with growth traits. The present study indicates that growth, gonad yield and most gonad quality traits could be improved by selection with moderate to high potential. Indirect selection should be applied on gonad traits using growth traits as secondary traits. The present study provides important theoretical guidance for future selective breeding programmes for S. intermedius.     

流沙湾养殖华贵栉孔扇贝体色多态性研究

对雷州半岛西部流沙湾养殖的华贵栉孔扇贝（Chlamys nobilis）群体进行了体色多态性研究。结果显示,在调查的10个苗种来源不同、总抽样数量为5 954个个体的养殖群体中,壳色可分为6类,分别是橘黄色（62.31%）、枣褐色（14.51%）、紫白色（12.46%）、橘黄间紫色（6.43%）、紫顶枣褐色（3.46%）和黄顶紫黄色（0.82%）;6类壳色群体的闭壳肌颜色均存在白、黄2色,且白色比例均显著高于黄色,其中黄色闭壳肌比例最高的是橘黄色（18.79%）;华贵栉孔扇贝成熟的生殖腺颜色分为黄、乳白2色,分别代表雌性和雄性,性比与闭壳肌颜色相关。研究表明,华贵栉孔扇贝壳色以橘黄色为主（P〈0.05）,闭壳肌颜色以白色为主（P〈0.05）;壳色与闭壳肌颜色存在一定的相关性,带“黄”壳色个体黄色闭壳肌比例较高（P〈0.05）;黄色闭壳肌群体雌性比例显著高于雄性（P〈0.01）。     

哺乳动物性腺特异表达基因研究进展

在哺乳动物配子发生过程中,需要一个严格的阶段性和细胞特异性的基因表达程序。近年来,随着基因克隆、表达及功能研究技术的发展与应用,发现了许多配子发生过程中发挥特定作用的阶段特异和细胞特异表达的基因,有的已被证明在配子发生中起重要作用,但生殖细胞在分化及发育时受其调节的分子机制尚未了解,需要进行更加广泛深入的研究。文章综述了动物性腺特异表达基因研究的最新进展,旨在为从事该领域研究的工作者提供参考信息。     

中华绒螯蟹性腺香气品质评价方法

采用顶空固相微萃取-气-质联用技术(HS-SPME-GC-MS),对采自阳澄湖的特级、1级、2级的雄性及雌性中华绒螯蟹(Eriocheir sinensis)性腺中的香气成分进行了鉴定并以内标法对其定量。6种中华绒螯蟹样本中共检测到8类58种挥发物,采用主成分分析法(PCA)对标准化后的8类香气成分的浓度值进行分析,以主成分综合得分作为评价依据得到:特级和1级雌蟹性腺的香气品质最好,且呋喃类、醇类、芳香类、醛类4类成分对其贡献显著,是表征"高品质风味"的特征性香气成分;将性别因素统一考虑后,中华绒螯蟹等级越高,性腺香气品质越好;相同等级条件下,雌蟹性腺香气评分高于雄蟹。结果证实,主成分分析法可用于建立不同中华绒螯蟹性腺香气品质的评价模型。本研究旨在为深入探讨如何改善中华绒螯蟹的风味特性提供理论参考。