黑褐新糠虾血细胞形态及其与日本新糠虾对溶藻弧菌敏感性的比较

实验采用Giemsa与Wright' s两种染色方法对黑褐新糠虾血细胞进行染色,根据血细胞大小,所含颗粒与否,颗粒多少和核质比将其分型,并对各型血细胞所占比例进行统计.结果表明,通过比较Giemsa染色与Wright's染色两种方法的染色时间和效果,Wright's染色更加适合糠虾血细胞.通过染色,将黑褐新糠虾血细胞分为3种类型,它们分别为透明细胞、半颗粒细胞和颗粒细胞.它们的胞体大小依次增大,核质比依次降低.对此3种类型血细胞比例分别统计后发现,颗粒细胞所占比例最多约( 48.38％±0.05％),其次是半颗粒细胞约为(35.22％±0.04％),最少的为透明细胞约为(16.40％±0.01％).对不同浓度溶藻弧菌的感染试验发现,日本新糠虾在较短的时间内出现死亡,即48h,而黑褐新糠虾72 h出现死亡,各浓度组中日本新糠虾死亡率均高于黑褐新糠虾.黑褐新糠虾相对日本新糠虾来说,对溶藻弧菌具有较低的敏感性,可能与其血细胞中颗粒和半颗粒比例较高有关.     

菲、芘、壬基酚对黑褐新糠虾的急性毒性

通过测定菲、芘、壬基酚对黑褐新糠虾的急性毒性,探讨了这三种难降解有机物对黑褐新糠虾的24h、48 h、72 h和96 h半致死浓度(LC50 ).结果表明菲对黑褐新糠虾24 h、48 h、72 h和96 h的半致死浓度分别为530 μg/L、310 μg/L、166 μg/L和126 μg/L;壬基酚对黑褐新糠虾24 ...     

一株非PSP产毒的亚历山大藻对黑褐新糠虾的急性和慢性毒性影响

报道了一株非PSP产毒的相关亚历山大藻(Alexandrium affine,株AC-1)对甲壳类生物黑褐新糠虾(Neomysis awatschensis)的存活、生长及种群繁殖的研究结果.通过研究发现,该藻对黑褐新糠虾有急性致死作用,96 h LC50为5 000 cells·mL-1.研究该藻各组分:藻液、藻细胞重悬液、藻细胞培养过滤液、内容物对糠虾存活的影响时,发现只有藻液和藻细胞重悬液显著降低了糠虾存活率,过滤液和内容物也有影响,但不显著,表明相关亚历山大藻活体藻细胞的毒性最强.通过对糠虾63 d的慢性毒性实验研究,发现在密度为50 cells·mL-1藻液中,糠虾的繁殖就受到了不利影响.试验进行到63 d结束时,糠虾日最高产虾数、总产幼虾数、总产虾天数都明显减少,初次产虾时间推迟,繁殖中断增加.且该藻对黑褐新糠虾亲虾的存活、生长也有一定的影响,糠虾亲虾的存活率为对照的71%,而体长和体重分别为对照组的87.3%和97.8%,但差异尚不显著(P＞0.05).可见,相关亚历山大藻(AC-1)虽然不产生PSP毒素,但也能对甲壳类生物的种群数量和资源补充产生不利影响.     

盐度对黑褐新糠虾成活的影响

<正>糠虾是一种小型虾类,对环境因子较为敏感,常被用作重金属、化工污染及环境污染研究的试验生物,美国环保局将巴西拟糠虾(Mysidopsis bahia)作为一种毒性测试的标准试验生物,欧洲把普通新糠虾(Neomysis integer)作为西欧河口系统的毒性试验生物。国内学者将我国的糠虾种类应用于环境监测中,并进行有关糠虾的毒性试验研究,周名江等报道了以黑褐新糠虾为标准试验生物的急性毒性测试方法。糠     

日本新糠虾雄性生殖系统发育的组织学

对日本新糠虾（Neomysis japonica）雄性生殖系统的发生及其与外部特征变化的关系进行详细观察与总结。结果表明：日本新糠虾雄性生殖系统的发生与外部特征变化有明显的对应关系。日本新糠虾雄性生殖系统中,首先出现的是精索（孵出后的8~14d）,其内含有大量精原细胞,此时外部性征尚未出现。孵出后14~20d时出现外部性征雏形（交接器和雄叶均透明无刚毛,第4腹肢雏形）,其内部生殖系统进一步发育,出现精子细胞囊。至孵出后24~30d时,日本新糠虾雄性生殖系统发育成熟,已具备完整的雄性生殖系统和成熟的外部性征。本研究结果将为糠虾普通生物学研究及人工培育提供科学的理论资料。     

日本新糠虾雄性生殖系统发育的组织学研究

对日本新糠虾(Neomysis japonica)雄性生殖系统的发生及其与外部性征变化的关系进行详细观察与总结。结果表明,日本新糠虾雄性生殖系统的发生与外部性征变化有明显的对应关系。日本新糠虾雄性生殖系统中,首先出现的是精索(孵出后的8～14d),其内含有大量精原细胞,此时外部性征尚未出现。孵出后14～20d时出现外部性征雏形(交接器和雄叶均透明无刚毛,第4腹肢雏形),其内部生殖系统进一步发育,出现精子细胞囊。至孵出后24～30d时,日本新糠虾雄性生殖系统发育成熟,同时也具备了成熟的外部性征。     

盐度和漂白粉对东方新糠虾的急性胁迫影响

在水温(26.5±0.5)℃的条件下,探究了盐度和漂白粉对体长为(0.66±0.07)cm的东方新糠虾(Neomysis orientalis)的急性毒性作用。实验结果表明:东方新糠虾适宜的盐度范围较广,对低盐的耐受能力更强,其最适盐度范围为15～25。漂白粉对东方新糠虾在24、48、72 h的半致死浓度分别为2.639、1.149、0.812 mg/L,安全浓度为0.065 mg/L。     

温度对白斑狗鱼早期发育和生长的影响

通过对7个不同温度组白斑狗鱼初孵仔鱼的14 d连续取样观察,分析比较不同的培育水温对白斑狗鱼的早期发育和生长的影响.试验结果表明,在适宜的温度范围内增温对白斑狗鱼早期生长发育的影响效果明显,且不会降低成活率,从而可缩短育苗时间,降低生产成本,减少风险.     

冷冻和鲜活糠虾对灰海马繁殖力的影响

为研究用冷冻糠虾替代鲜活糠虾作灰海马亲鱼饵料的可行性,通过饲喂试验,比较了鲜活糠虾(A组)和冷冻糠虾(B组)对灰海马产仔数量、胚胎发育时间、初孵仔鱼的体长、体质量及其在15日龄时的生长和成活率的影响.结果表明,水温28℃,盐度33时,两个处理组在产仔数量、胚胎发育时间、初孵仔鱼的湿重、体长、肥满度、15日龄时的湿重增量、湿重的绝对增长率均无显著差异,而A组15日龄仔鱼体长的增量为1.464 cm,显著高于B组的0.699 cm(P=0.039),A组的体长绝对增长率为0.100,极显著高于B组的0.050(P =0.0039).A组仔鱼的成活率为97.65％,极显著高于B组的66.72％(P =0.007).相对于冷冻糠虾,鲜活糠虾能够更好地满足灰海马亲鱼的营养需求,提高子代的生长性能和成活率.     

Effects of elevated ambient histamine level on survival, growth, sexual maturity and tissue histamine accumulation of the mysis Neomysis awatschensis and Neomysis japonica Nakazawa

In Asia, trash fish have been routinely used in aquaculture often due to their local availability and lower costs compared to formulated feed. However, stale trash fish contain high levels of biogenic amines, which have been reported to be harmful to poultry and some aquatic animals. The present study elevated the effects of histamine levels in the water on survival, growth, sexual maturity and tissue histamine accumulation of two estuarine mysis, Neomysis awatschensis and Neomysis japonica Nakazawa. Newly hatched neonates of each mysis species were cultured in brackish water containing 0 (control), 5, 10 and 15 mg/L histamine until they reached sexual maturity. The results showed that compared to the control, survival of N. awatschensis was significantly lower in both 10 and 15 mg/L histamine treatments (69.5 and 62.5% vs. 86.5%). In the case of N. japonica Nakazawa, significantly lower survival was found for the 15 mg/L treatment (53.9% vs. 72.4%) (P < 0.05). In a separate experiment, neonates of each mysis species were cultured individually (15 neonates/treatment) to assess the sub-lethal effects of histamine. It was shown that at the level of 15 mg/L, histamine had a significant impact on body weight and length of sexual matured N. japonica Nakazawa, which were only 87.7 and 78.7% of that of the control. However, no significant difference in intermolt period was detected. In the case of N. awatschensis, no significant differences in both body weight and length among treatments were detected (P > 0.05) but the intermolt period was substantially prolonged at all histamine levels tested when compared to that of the control. Meanwhile, the timings required to reach sexual maturity for both male and female of the two mysis were generally increased with increasing histamine level, and such differences were often statistically significant (P < 0.05). Compared to the control, the tissue histamine concentration of the mysis increased significantly at histamine concentrations of 10 and 15 mg/L for N. japonica Nakazawa (P < 0.05). In the case of N. awatschensis, however, no significant differences were found among all treatments. Our findings indicate that histamine had clear negative effects on both mysis species although their responses and sensitivity appeared somewhat different. Our results suggest that further research is needed to assess the effects of water borne histamine on various aquatic animals.     

Utilization of Neomysis integer Leach (Crustacea,Mysidacea) by rainbow trout (Salmo gairdneri Richardson) parr in brackish water

The utilization of Neomysis integer by rainbow trout parr was studied and compared with the utilization of conventional fish feeds. Under brackish water conditions Neomysis pellets are just as efficient as conventional feeds in respect of growth. The feeding efficiency is comparable with that obtained with krill. Suggestions are made for obtaining this natural food via filters at power stations or attracting it with light traps (phototaxis). Neomysis should be used as an additional food wherever it is present in appreciable quantities.     

Effects of enriched Artemia nauplii on production, survival and growth of the mysid shrimp Mysidopsis almyra Bowman 1964 (Crustacea: Mysidacea)

The effects of enriched Artemia nauplii on larvae production and survival and growth of the mysid Mysidopsis almyra Bowman 1964 are compared. There were no significant differences (P > 0.05) in production between mysids fed the Artemia nauplii (133 ± 69 mysids day⁻¹) and mysids fed the enriched nauplii (139 ± 82 mysids day⁻¹). No differences in size of newly hatched mysids or mysid growth to 15 days (P > 0.05) were found between the two diets. Survival was significantly higher (P < 0.05) for mysids fed the enriched nauplii (59.1%) compared with mysids fed Artemia nauplii (41.4%).     

Nutritional quality of Metamysidopsis insularis Brattegard (Crustacea: Mysidacea)

In natural conditions the mysid Metamysidopsis insularis is commonly found in the littoral lagoon of Margarita Island (Venezuela). It is used as live food in the marine fish culture. However, its nutritional quality is not well documented. In the present study we analysed the nutritional value (total protein, carbohydrate and lipids profile) of M. insularis. The mysids were collected in La Restinga lagoon (Margarita Island, Venezuela). Levels of total proteins, lipids and carbohydrates were 700 ± 28.5, 160 ± 13.9 and 20 ± 0.90 g kg^?1 respectively. The lipids classes were 427 ± 2, 106 ± 98, 287 ± 113 and 179 ± 87 for phospholipids, triglycerides, cholesterol and cholesterol esters respectively. The fatty acids profile, determined by gas chromatography, showed important concentration of fatty acids for the metabolism of marine organism, such as 16:0, 18:0, 18:2n‐6, 18:3n‐3, 18:4‐3, 20:5n‐3 and 22:6n‐3; attaining levels of 27.49% in PUFA n‐3 and 2.92% in n‐6. The relation of eicosapentaenoic acid/docosahexaenoic acid was 2.1 ± 0.15. The results support the use of M. insularis as food for species of fish and crustaceans under culture conditions.     

Effects of delayed first feeding on larval growth,survival and development of the sea cucumber Apostichopus japonicus (Holothuroidea)

The time of first feeding is an important factor for establishing successful exogenous feeding in aquaculture hatcheries as it is crucial for larval survival and growth. The effects of delayed first feeding by the sea cucumber Apostichopus japonicus larvae were investigated. Groups of larvae were fed immediately after completion of the digestive tract (fed control) or starved for 24, 48, 72, 108 and 120 h post fertilization. The growth rates of A. japonicus larvae were the same as those of the control group when first feeding was delayed for less than 72 h. When the period of starvation was beyond 72 h, growth rates were reduced. The fed control group had the highest percentage of late auricularia larvae (70.0%) on day 11, followed by the groups starved for 24, 48, and 72 h, respectively, which had 35.00%, 43.48% and 41.67% of late auricularia larvae. When larvae were starved for more than 72 h, the percentage of late auricularia larvae never exceeded 12.0%. Most larvae halted in development and were deformed before reaching metamorphosis when starved for 108 and 120 h. Prolonged exposure to starvation (more than 48 h) resulted in a significant decrease in percentage of larvae reaching settlement. The point‐of‐no‐return (PNR) of A. japonicus larvae was calculated 110.4 h. Ratios of stomach length to total length, stomach width to total width were more sensitive to starvation than other larval morphometrics. To avoid mortality and obtain adequate growth and development, A. japonicus larvae in commercial culture should be fed within 48 h of the completion of the digestive tract.     

Effects of cortisol on growth and development in tilapia larvae,Oreochromis mossambicus

Treatment of one-day-old yolksac larvae of tilapia (Oreochromis mossambicus), by immersion in cortisol solution for two weeks, significantly enhanced growth. The standard length, tail length, head width and wet weight showed dose-dependent increases at concentrations of cortisol (hydrocortisone) from 0.05 ppm to 0.5 ppm, with no further increase at 1.0 ppm. However, cortisol at 5.0 ppm retarded the growth of the larvae without causing any morphological abnormality. Yolk absorption and the onset of free-swimming activity in the larvae were also accelerated by cortisol treatment.