萼花臂尾轮虫的培养

在室外自然条件下，用简易法培养萼花臂尾轮虫，一般每毫升为50－80个，最高达184个／毫升。 基本上满足批量培育鱼、虾苗种需要。简易法生产轮虫的设备简单、投资少，有一定技术条件的鱼种场均可实施。     

pH对萼花臂尾轮虫种群动态和休眠卵的影响↑（*）

应用种群累积培养法,研究了pH3.5～11.5(间隔1.0)之间萼花臂尾轮虫(Brachionuscalyciflorus)的种群动态及休眠卵的形成。结果表明,该轮虫在pH5.5～10.5为正增长,pH7.5时种群增长趋势最好;pH4.5时为负增长;pH3.5和11.5分别是该轮虫存活下限和上限。pH对轮虫休眠卵的产量和形成效率、平均混交雌体百分率和受精率皆具极显著影响。7.5是该种轮虫休眠卵规模化生产的最佳pH值,此时休眠卵的产量和藻类食物的形成效率最大,分别为(132567±20264)/(20ml·6d)和(11.05±1.69)/(6×106cells)。     

萼花臂尾轮虫的培养技术

萼花臂尾轮虫是水产苗种开食和早期培育阶段的优良饵料，可以在淡水中培养。传统养鱼的肥水下塘经验，是利用藻类、轮虫、枝角类等的混合群体供饵，利弊兼有。本研究采用单胞藻、酵母及光合细菌单独培养萼花臂尾轮虫，可获得纯净的适口饵料，为工厂化育苗提供饵料保证。     

三种农药对萼花臂尾轮虫种群变动的影响初探

本文报道了不同温度下萼花臂尾轮虫 (Brachionuscalyciflorus)的种群增长参数和生长周期 ,结果表明 :其内禀增长率rm (h-1)、净生殖力R0 和世代时间T (h)分别为 :0 0 6 ,15 70和 37 70 (2 0 +1℃ ) ;0 0 6 ,17 5 2 ,36 0 0 (2 5 +1℃ )。种群的最大密度随温度的升高增加 ,而种群到达高峰所需时间也随着温度升高而缩短。在三种农药的实验中 ,敌百虫、噻嗪酮、氯氰菊酯在 2 4h中的LC50 分别为 :32 1 6mg/L ,2 6 3 5mg/L ,36 8 5 μg/L。     

褶皱臂尾轮虫不同时期休眠卵的超微结构

分别用光学显微镜、扫描电子显微镜和透射电子显微镜对褶皱臂尾轮虫(Brachionusplicatilis)新产的和隔年的休眠卵形态结构进行观察。结果表明,两个时期的休眠卵外壳结构有区别,隔年卵外壳较薄,壳纹不明显;新卵外壳厚,壳纹明显。进行轮虫休眠卵分类时应以后者为准。新产休眠卵无气室,而隔年休眠卵有气室。进一步观察表明,休眠卵气室中的气体由休眠期间的代谢活动而产生。扫描电镜下,新产休眠卵有2层卵膜,隔年休眠卵有3层卵膜;透射电镜下,二者均为3层卵膜,不同时期休眠卵的每层卵膜厚度及细微结构有所差别。这两个时期的休眠卵胚胎结构上均有2层,但内含物有所不同。     

辛基酚对萼花臂尾轮虫毒性效应的研究

应用生态学毒理学方法,研究了环境雌激素辛基酚(OP)对萼花臂尾轮虫毒性效应。包括24h急性毒性、慢性浓度(0.01~0.16mg/L)对轮虫发育阶段、2d的种群增长率r及7d休眠卵产量影响。结果显示:OP对轮虫24h的急性毒性LC50为0.91mg/L;OP浓度0.08、0.16mg/L显著降低轮虫的生殖前期、生殖期和寿命历时,0.04mg/L以上降低轮虫的生殖量;OP浓度0.08、0.16mg/L显著降低轮虫2d的r,0.01mg/L及以上浓度显著降低轮虫7d的休眠卵产量。以上研究表明:OP对轮虫的生殖具有干扰作用,其中轮虫7d休眠卵产量为监控水体OP污染最敏感的指标。     

马拉硫磷和甲氰菊酯对萼花臂尾轮虫生殖的影响

研究了不同浓度马拉硫磷(malathion)(0.03、0.3、3.0、30.0、300.0、3000.0μg/L)和甲氰菊酯(fenpropath-rin)(0.004、0.04、0.4、4.0、40.0、400.0μg/L)对萼花臂尾轮虫(Brachionus calyciflorus)3d种群增长率、携卵雌体数/非携卵雌体数、混交雌体百分率、混交雌体受精率及7d休眠卵产量影响。结果表明,马拉硫磷、甲氰菊酯对种群增长率、混交雌体百分率、混交雌体受精率及7d休眠卵产量有显著影响;马拉硫磷对携卵雌体数/非携卵雌体数无显著影响,但甲氰菊酯有显著影响。马拉硫磷对轮虫休眠卵产量最低效应浓度(LOEC)为0.3μg/L,对混交雌体百分率LOEC为30.0μg/L,对种群增长率和混交雌体受精率LOEC为300.0μg/L;甲氰菊酯对轮虫休眠卵产量最低效应浓度0.04μg/L,对混交雌体百分率和携卵雌体数/非携卵雌体数LOEC为4.0μg/L,对种群增长率和混交雌体受精率LOEC为40.0μg/L。试验显示,马拉硫磷和甲氰菊酯对轮虫生殖存在差异,轮虫休眠卵产量可以用来监测和评价2种杀虫剂潜在的影响。     

萼花臂尾轮虫室内规模培养技术

萼花臂尾轮虫具有生长快、繁殖力强、营养丰富等特点,是水产苗种开食和早期培育阶段的优良饵料,可以在淡水中培养。结合轮虫室内高密度培养特点及自身实践经验,对萼花臂尾轮虫室内规模培养技术作简要总结。     

盐度突降对褶皱臂尾轮虫存活及休眠卵形成的影响

以单体培养、群体累积试验2种方法,研究了盐度突降对褶皱臂尾轮虫存活及休眠卵形成的影响,旨在为褶皱臂尾轮虫及其休眠卵的规模化生产提供理论指导.结果表明褶皱臂尾轮虫在盐度2以下难以存活;生活在盐度20以上海水中的褶皱臂尾轮虫,盐度突降到4以上不会造成大量死亡;大幅度降低盐度可促进休眠卵的形成,最佳降盐幅度为从正常培养时的20以上降至6.     

由休眠卵孵化的褶皱臂尾轮虫的成长

褶皱臂尾轮虫Brachionus plicatilis0．F．Muller虽被广泛用作海产鱼种苗生产的初期饵料，但培育仔鱼体较小的鱼种，在刚开始摄饵时需选择小型轮虫(以仔轮虫为主)。为此，了解培养槽中轮虫的孵化、成长过程中，不必测定其被甲长而推知小型轮虫的出现时间，即亟待开发的有效的小型轮虫生产技术。     

Effect of disinfectants on the hatching of marine rotifer resting eggs Brachionus plicatilis Müller

Scanning electron microscopy indicated that stored resting eggs of the marine rotifer Brachionus plicatilis Müller were colonized by numerous bacterial cells that affect the hatchability of resting eggs. The effectiveness of chemical disinfectants on the hatching of the resting eggs was studied using selected chemicals and antibacterial drags. The hatching success rate of the fresh and stored eggs was 26 ± 5.8% and 0%, respectively. Sodium hypochlorite (1.0 p.p.m.) increased the hatching rate to 48 ± 1.3% in freshly-collected and 28 ± 1.8% in stored eggs. Physical disintegration of the bacterial mat occurred after 1 h of treatment with sodium hypochlorite. Among antibacterial drugs, sodium nifurstyrenate (Erubaju) enhanced the hatching success rate to 40 ± 1.2% and 20 ± 1.1% for the freshly-collected eggs and stored resting eggs, respectively. However, tetracycline and oxytetracycline did not significantly influence the hatching of the stored eggs. These observations are discussed in relation to the development of an improved method for the processing and hatching of rotifer resting eggs.     

盐度对褶皱臂尾轮虫存活及其休眠卵孵化的影响

本文报道了不同盐度对褶皱臂尾轮虫存活及其休眠卵孵化的影响。采自低盐度和较高盐度水体中的褶皱臂尾轮虫休眠卵，在纯水和５０‰的高盐度孵化液中都不能孵化，但在淡水和５－４０‰工的孵化液中均有不同比例的孵化，其中以５‰盐度中的孵化率最高。采自２０‰盐度的休眠卵在１５‰盐度中孵化的幼轮虫在５－３０‰盐工中，３小时内，其存活率均达９０％以上，不必通过驯化，可直接投喂到不同盐度的育苗池。而采自４‰盐度的休眠卵５     

Effect of temperature on resting egg formation of the tropical SS-type rotifer Brachionus rotundiformis Tschugunoff

ABSTRACT:   Tropical minute rotifer strains (SS-type) induce mixis at 30–35°C but sexual reproduction and resting egg formation do not proceed well due to rapid environmental change. The present study examined the effect of temperature regulation on rotifer Brachionus rotundiformis (Langkawi strain, SS-type) resting egg formation in small (500 mL in culture volume)- and large-scale (500 L in culture volume) experiments. Rotifers were cultured at 30°C in 15–17 p.p.t. seawater with an initial density of 1 individual (ind.)/mL. After 4 days, when cultures were in exponential growth stage with active mixis induction, the culture temperature of the experimental rotifers was changed to 25°C. Control rotifers were cultured at 30°C throughout the experiment. Fresh or frozen Nannochloropsis oculata and condensed freshwater Chlorella vulgaris were used as the rotifer diets in the small- and large-scale experiments, respectively. Significantly higher resting egg production was observed with the experimental rotifers (30→ 25°C) versus the control rotifers. In the large-scale trial, experimental rotifers produced 2.6 × 10⁶ resting eggs during a 9-day experiment, which was 1.6-fold more than the control rotifers. Moreover, the efficiency of resting egg formation was found to increase by a factor of 1.8. The present study indicates that decreasing culture temperature from 30 to 25°C after active mixis increased resting egg formation in B. rotundiformis (SS-type).     

不同消毒剂对黑鲷受精卵孵化的影响

采用室内静水孵化的方法,在水温18.5℃、盐度1.018条件下,研究了不同浓度甲醛溶液、过氧化氢水溶液、聚维酮碘溶液对黑鲷受精卵孵化的影响.结果表明:聚维酮碘处理组孵化率显著低于对照组,甲醛、过氧化氢处理组与对照组孵化率差异不显著;甲醛和聚维酮碘处理组与对照组孵化所需时间相接近,显著高于过氧化氢处理组.因此,在黑鲷育苗过程中可用浓度为500 mg/L或1 000 mg/L过氧化氢溶液处理受精卵15 min以提高受精卵的孵化率,同时还可以缩短孵化时间.     

Fatty acid profiles of two freshwater fish larvae (gudgeon and perch) reared with Brachionus calyciflorus Pallas (rotifer) and/or dry diet

The efficiency of the rotifer Brachionus calyciflorus Pallas as a nutritional source for rearing larvae was studied in a coldwater cyprinid, the gudgeon Gobio gobio (L.), and in a percid, the perch Perca fluviatilis L., through their composition in fatty acids. Rotifer intake affected the fatty acid profiles of the larvae significantly, with an especially remarkable presence of the linoleic family. In gudgeon fed with rotifers, the polyunsaturated fatty acids (PUFA) reached 10.98% of the dry weight of the sample. This rate was highly influenced by the presence of the acids C18:2n-6 and C22:6n-3 which represented 66% of the total PUFA. In perch fed exclusively with rotifers, the PUFA represented 7.27% of the dry weight. In both cases, the ratio n-3/n–6 decreased by 75% and 73% after 10 days of feeding with B. calyciflorus. This variation was probably due to the exogenous supply in acids of the linoleic family through the rotifers and to the fact that these two species of fish seem to favour the mobilization of the n-3 PUFA such as C22:6n-3 for growth and survival. Moreover, with the utilization of rotifers. the reactions of elongation and desaturation from the C18:2n-6 and C18:1n-9 seemed to be much more important in the larvae. Lastly, the transition from a diet based on rotifers to one made up exclusively of frozen Artemia nauplii led to a significant reduction of fatty acids in fish. It reached 60.2% and 26.5% of the total fatty acids in the gudgeon and perch, respectively, and was observed especially at the level of the PUFA. On the other hand, a slight increase of the ratio n-3/n-6 was pointed out in the perch fed a mixed diet (co-feeding with rotifers and dry food), a phenomenon probably due to the reduction of C18:2n-6 in the larvae.