人工诱导栉孔扇贝雌核发育二倍体的初步研究

2004年5~6月,用紫外线照射法使精子遗传物质失活,结合用6-二甲基氨基嘌呤(6-dime-thylaminopurine,6-DMAP)处理受精卵抑制第2极体释放,诱导栉孔扇贝雌核发育二倍体。采用中心波长254nm、光照强度800μw/cm2·s的紫外线照射栉孔扇贝精子50s,然后立即与正常卵子授精,在20℃水温下,受精后35~40min光镜下观察到20%~30%卵子排出第1极体时,分别以40、50、60、70、80mg/L的6-DMAP持续处理受精卵10、15、20min,染色体计数法检测各处理组二倍体率,从而筛选诱导栉孔扇贝雌核发育二倍体两因素的最佳组合。结果表明,6-DMAP的浓度和持续处理时间对二倍体诱导率和D形幼虫率影响较显著,6-DMAP浓度以60、70mg/L较为适宜,最佳处理时间为20min,综合考虑,60mg/L6-DMAP处理20min组得到了最佳效果,二倍体率为57.6%、D形幼虫率22.25%。随后对筛选出的最佳条件组担轮幼虫进行了大量的染色体统计和流式细胞仪分析,结果基本一致,二倍体率分别为53.7%和57.3%。     

南方糙海参的人工催产与育苗试验

糙海参（Holothuria scabra）是中国南方优质的热带海参经济品种,试验首次成功在国内综合运用升温等多种刺激方法人工诱导糙海参产卵,并进行了批量人工育苗。2010年4~6月,共进行人工催产试验10次,催产亲参243头,5次试验产卵,催产成功率50%,共获得受精卵1 652.72104粒,孵出糙海参幼体1 226.74104头,总体孵化率74.23%;在水温27.5~30.0℃条件下,受精卵完成胚胎发育需要32.5 h;利用其中部分幼体开展后期人工育苗,经过21 d培育,获得糙海参早期稚参（0.1 cm）19.43104头,苗种培育成活率16.7%;经过32 d培育获得大规格后期稚参苗（0.3~0.5 cm）2.46104头,培育成活率2.12%。试验的成功对下一步开展北部湾海域糙海参的天然种群恢复和在华南地区进行糙海参的人工养殖与开发具有重要意义。     

南方糙海参的人工催产与育苗初步试验

糙海参（Holothuria scbra）是中国南方优质的热带海参经济品种,试验首次成功在国内综合运用升温等多种刺激方法人工诱导糙海参产卵,并进行了批量人工育苗。2010年4—6月,共进行人工催产试验10次,催产亲参243头,5次试验产卵,催产成功率50％,共获得受精卵1652．72×10^4粒,孵出糙海参幼体1226．74×10^4头,总体孵化率74．23％;在水温27．5～30．0℃条件下,受精卯完成胚胎发育需要32．5h;利用其中部分幼体开展后期人工育苗,经过21d培育,获得糙海参早期稚参（0．1cm）19．43×10^4头,苗种培育成活率16．7％;经过32d培育获得大规格后期稚参苗（0．3～0．5cm）2,46×10^4头,培育成活率2．12％。试验的成功对下一步开展北部湾海域糙海参的天然种群恢复和在华南地区进行糙海参的人工养殖与开发具有重要意义。     

性外激素诱发中华乌塘鳢产卵的初步研究

在陶瓷人工产卵管道内吊挂性外激素的研究表明,卵巢提取液对雄鱼的吸引作用大于雌鱼,而精巢和贮精囊提取液对雌鱼的吸引作用则大于雄鱼,17α-P、17α,20β-P和PGE2对雌鱼和雄鱼均具有相似的吸引作用。雌鱼在管道内的产卵次数、产卵量以及成熟卵的受精率均与产卵管道内吊挂的性外激素种类有关,17α,20β-P和PGE2两个实验组产卵次数最多,其中PGE2实验组的产卵量和受精率最高。17α-P在贮精囊和精巢提取液中的含量显著高于卵巢提取液(P<0.05);贮精囊提取液中PGE2和PGF2α的含量分别显著高于精巢提取液和卵巢提取液(P<0.05);提取液中PGE2和PGF2α的含量均依次为贮精囊提取液>精巢提取液>卵巢提取液。卵巢提取液刺激雄鱼所引起的平均EOG高于雌鱼,而精巢和贮精囊提取液刺激雌鱼所引起的平均EOG高于雄鱼,雌鱼和雄鱼对17α-P、17α,20β-P、PGE2和PGF2α刺激所产生的平均EOG,以PGE2为最高。     

Triploidy induction in Australian greenlip abalone Haliotis laevigata (Donovan) with cytochalasin B

Triploid induction in Australian greenlip abalone, Haliotis laevigata (Donovan), was conducted by blocking the formation of the second polar body using cytochalasin B (CB). Twenty minutes after fertilization, the zygotes of greenlip abalone were treated with four CB concentrations (0, 0.25, 0.5 and 0.75 mg L⁻¹) for 10, 15 and 20 min. The ploidy of resultant larvae was determined using flow cytometry at 72-h post fertilization. Our study showed that fertilization, hatching, survival and induced triploidy of abalone larvae were significantly affected by the CB concentration and treatment duration. The effective range of CB concentration for triploid induction on greenlip abalone was 0.5–0.75 mg L⁻¹ with an induction duration of 10–15 min. The results indicate that the most effective treatment combination for triploid induction in greenlip abalone is 0.5 mg CB L⁻¹ for 15 min starting at 20-min post fertilization.     

Induction of spawning and artificial incubation of eggs in the edible snail Pomacea urceus (Muller)

The neotropical freshwater gastropod Pomacea urceus is amphibious, herbivorous and attains a size of 145 mm. The snail fetches a high price of $US 5/kg, and current demand is met by collection from the wild, leading to over-exploitation. This is a potential aquaculture species, but there is the need for hatchery production of juveniles, since collection of seedstock from the wild is difficult. Wild-collected adult P. urceus were placed in 0.4 m² concrete troughs filled with soil and water. Mating was induced by a decrease in water level, and after mating, the snails burrowed into the substratum where egg-laying occurred. The recently laid eggs were carefully removed from the females and placed into darkened aquaria where the temperature was maintained at 27±3 °C and the humidity was kept above 80%. After an incubation period of 21 to 34 days, young crawling snails emerged. Mean survivorship was 96%.     

5种化学物质诱导九孔鲍精卵排放的效果比较

九孔鲍是我国东南沿海重要的鲍养殖品种,研究它的精卵排放具有重要意义。试验通过使用过氧化氢、利血平、绒促激素、促黄体素释放激素、孕酮等5种药物,分别配制不同浓度梯度,对壳长6.0~8.0cm,体重约17.0~25.0g的九孔鲍亲鲍个体注射0.02ml溶液,以研究其催产效果。结果表明,过氧化氢的效果最好,利血平次之,绒促激素、促黄体素释放激素和孕酮3种药物在这次的试验浓度中都没有明显效果。设定的4个过氧化氢浓度:4.98×10-6ml/只、3.73×10-6ml/只、2.49×10-6ml/只和1.24×10-6ml/只,均可使雌、雄亲鲍较快地排放出精卵;尤其以4.98×10-6ml/只的浓度催产效果最好,不仅效应时间短,而且雌、雄鲍排放率高。试验中的5种药物及浓度未见对亲鲍有明显的损害作用。     

紫薄鳅的人工繁殖初步试验

<正>紫薄鳅Leptobotia taeniaps(Sauvage)属鲤形目鳅科沙鳅亚科薄鳅属。分布于长江中、上游及其附属水体,属底栖性鱼类,喜生活在流水环境中,食物为底栖无脊椎动物。     

Growth performance and feed utilization of Haliotis tuberculata coccinea (Reeve) juveniles from the Azores (north-eastern Atlantic Ocean): An assay of three mono algae diets

We assessed the dietary value of available seaweeds (Ulva lactuca, Ulva intestinalis, and Sargassum vulgare) as food for juvenile abalone Haliotis tuberculata coccinea. During the 6 weeks that the experiment lasted, initial shell length and weight increased from 13.95 ± 0.32 mm to 15.30 ± 0.30 mm and from 0.39 ± 0.02 g to 0.47 ± 0.03 g. Ulva lactuca diet resulted in higher shell growth rate (58.47 ± 16.76 μm day^?1), SGR (1.15 ± 0.47%.day^?1), weight gain (65.5% ± 33.3), and PER (1.56 ± 0.31), possibly thanks to its higher crude protein content. Both green algae (U. lactuca, U. intestinalis) prove to support the growth of H. tuberculata coccinea. However, they might not be appropriate for an optimal intensive aquaculture production; further research should be conducted to find more efficient diets for juvenile abalone.     

军曹鱼池塘人工育苗技术的初步研究

在池塘进行军曹鱼Rachycentron canadum人工育苗研究,通过解剖消化肠道以确定仔鱼开口的生物饵料种类。结果显示,个体较大的桡足类无节幼体比轮虫更适合作为军曹鱼仔鱼的开口饵料;对体长和体重进行测定,军曹鱼在鱼塘进行人工育苗,鱼苗生长迅速,7日龄的仔鱼体长达1cm,30d的鱼苗可长至15cm。     

美洲鲥室内人工育苗技术初探

为探究美洲鲥室内人工育苗的技术方法,对其受精卵孵化及苗种培育进行了初步的研究。在美洲鲥苗种培育过程中,用空气能制冷制热机组将受精卵孵化温度控制在17～19℃,苗种培育温度控制在19.0～20.5℃,并以池塘培养的生物饵料(轮虫、枝角类和桡足类等)作为仔鱼的开口饵料。试验结果:2017—2019年连续3年,每年4—8月收集美洲鲥卵,数量分别为277.96万、471.48万、2 226.32万粒,获得的受精卵分别为18.58万、74.47万、195.85万粒,受精率分别为6.68%、15.80%、8.80%;受精卵孵化后,仔鱼经30～50 d的室内水泥池培育,最终分别获得体长30～50 mm并已成功驯化摄食配合饲料的幼鱼9 392、40 083、78 600尾,育苗成活率分别为11.01%、15.00%、15.72%。试验获得了1套适合上海地区美洲鲥室内人工育苗的模式,可以为美洲鲥后续的人工育苗研究和规模化苗种培育生产提供技术参考。     

Evaluation of cytochalasin B (CB) treatments for triploidy induction in the blacklip abalone, Haliotis rubra (Leach, 1814)

The effectiveness of cytochalasin B (CB) treatments for inducing triploidy was evaluated in the blacklip abalone Haliotis rubra (Leach, 1814) in two orthogonal design experiments. The first experiment employed three dosages (DSs) of 0.25, 0.5 and 1.0 mg CB L^?1, three starting times (STs) of 5, 15 and25 min post fertilization and three treatment durations (TDs) of 10, 20 and 40 min, for a total of 27 treatments. The second experiment comprised of two DSs of 0.25 and 0.5 mg CB L^?1, five STs of 5, 15, 20, 25and 30 min post fertilization, and three TDs of 10, 20 and 40 min, for a total of 30 treatments. Water temperature was held at 17.5–18.5°C. Day 3 larvae were sampled for triploidy using flow cytometry (FCM) and survival. Optimal inductions were treatments starting at 15 or 20 min post fertilization and continuing for 40 min, and those initiated 25 or 30 min post fertilization for 20 or 40 min, using 0.5 mg CB L^?1. These treatments were all targeted at inhibition of the second polar body (PB2) formation and yielded triploidy rates of 84.8–89.5% coupled with (relative) survival rates of 20.1–52.1% in the first experiment, and corresponding rates of 86.5–96.5% and 33.0–74.1%, respectively, in the second experiment. A common and essential feature of these optimal conditions is that treatment must fully span the period of time for most of the eggs to extrude PB2. Treatments that resulted in suppression of the first polar body (PB1) formation induced triploidy levels below 71.5% and 57.6% in experiments 1 and 2 respectively. Treatments that had overlapping effects on both PB1 and PB2 extrusion led to triploidy rates above 80% but very low survival rates of 1.8% and 5.4% in experiments 1 and 2 respectively.     

Assessment of the physiological effect of altered salinity on greenlip (Haliotis laevigata) and blacklip (Haliotis rubra) abalone using respirometry

The early physiological response (3 days) of greenlip (Haliotis laevigata Leach) and blacklip (H. rubra Leach) abalone to a single abrupt change in salinity was monitored using a multi‐channel open‐circuit respirometer. The range of salinity tolerance for both species in this trial was 25–40 ppt. Indications from other trials were that a margin of 2 ppt outside this range will cause mortality. Serum volume was increased by reduced salinity as much as 25% in the short term, with equilibration of the concomitant whole body weight increase (9.2±0.5%) occurring within 1 h. The serum volume appeared to be decreased at high salinity. There was little underlying change in basal oxygen usage levels, but significant behavioural changes that affected overall oxygen consumption. Both high and low salinity appeared to reduce activity. Animals in low salinity exhibit partial recovery of activity levels after 1 day in a manner similar to other stress responses. Animals at high salinity (40 ppt) did not show recovery of activity levels over 3 days. Overall, these results suggest that greenlip and blacklip abalone will have little trouble tolerating moderately low‐salinity environments.     

Influence of water temperature on spawning induction and larval development of the sea squirt Halocynthia ritteri (Oka, 1906)

In order to establish a large-scale hatchery technique for the sea squirt Halocynthia ritteri , the influences of water temperature on spawning induction, larval development and survival of H. ritteri were studied under laboratory conditions. The larvae of H. ritteri exhibited high sensitivity to changes in temperature. As temperature increased from 10 to 21 °C, the duration of larval stage was inversely related to temperature and the time to reach attached larvae stage decreased from 42.0 to 59.4 h. The biological minimum temperature for the early development of H. ritteri was estimated to be 0.22 °C. In relation to temperature, quadratic equations showed significant fits to the data of spawning rate, fecundity, fertilization, larval survival and attachment. Optimal temperatures for spawning rate, fecundity, fertilization rate, larval survival rate and attachment rate were estimated to be 14.9, 14.7, 13.2, 14.1 and 14.7 °C respectively. It is concluded that the range of 13–15 °C is optimal for spawning and larval rearing of sea squirts.     

Preliminary data on the induction of ovulation in white sturgeon (Acipenser transmontanus Richardson)

Forty-six white sturgeon females captured prior to their spawning migration in the San Francisco Bay and during their spawning run in the Sacramento River were induced to ovulate with three different hormonal substances: white sturgeon and common carp crude pituitary extracts, and [D-Ala⁶] GnRH analogue. All three inducing agents were potent at the respective doses of 2.5 mg, 4.0 mg and 0.1 mg dry matter per kilogram of female body weight. The best ovulatory responses and egg fertilities were observed in fish administered hormonal treatment during the months of March and April. Fish captured prior to and during their spawning migration exhibited similar spawning success.     

The effect of temperature and conditioning interval on the spawning success of wild-caught blacklip (Haliotis rubra, Leach 1814) and greenlip (H. laevigata, Donovan 1808) abalone

Wild‐caught blacklip (Haliotis rubra, Leach 1814) and greenlip (H. laevigata, Donovan 1808) abalone fed a formulated feed were held at 16 or 18°C for different conditioning intervals ranging from 114 to 235 days and induced to spawn using ultraviolet‐irradiated seawater. They were conditioned again for a second identical period before another induction. For H. rubra, mean spawning rate of both sexes was higher in groups held at 18°C than at 16°C, as was the repeat spawning rate. Conversely, animals held at 16°C produced significantly more gametes than those at 18°C. Egg production peaked in groups held at 16°C for ≥165 days. While both mean and total sperm production of H. rubra varied significantly, both figures were always high. Unlike H. rubra, the spawning rate, repeat spawning rate and gamete production of both sexes of H. laevigata were higher when cultured at 16°C than at 18°C. Egg production peaked in groups conditioned at 16°C for ≥212 days. Both mean and total sperm production by H. laevigata were much lower than for H. rubra. This study demonstrates that year‐round hatchery production of seedstock of both species is possible providing broodstock are held under favourable environmental conditions, preferably 16°C.