冷冻等处理对不同孵化进程的卤虫卵存活率的影响

本文研究了冷冻、双氧水和干燥处理对处于不同孵化进程中的卤虫卵的存活率（孵化率）的影响。冷冻对未经孵化处理的卵的孵化率影响很小，冷冻1-8周，基本保持不变。孵化进行了3个小时的卤虫卵，冷冻8周后，其孵化率降低了10个百分点。孵化进行了6个小时的卤虫卵，冷冻8周后，其孵化率降低了31个百分点。孵化进行79个小时的卤虫卵，冷冻8周后，其孵化率降低740个百分点。处于不同孵化阶段的卤虫卵经冷冻处理8周后，再经3％双氧水处理10分钟和40℃干燥处理6小时，其孵化率表现为不同的特点。未经孵化处理卵的孵化率基本保持不变。孵化进行了3个小时的卤虫卵，其孵化率再次降低5个百分点。孵化进行了6个小时的卤虫卵，其孵化率再次降低了20个百分点。孵化进行79个小时的卤虫卵，其孵化率再次降低了37个百分点。     

几个因子对内蒙古自治区卤虫卵孵化率的影响

采用常温、冷冻和盐水浸泡的方法.用3％双氧水、3％甲醛和3％高锰酸钾处理卤虫卵,研究诸因子对卤虫卵孵化率的影响。试验结果表明:产于内蒙古自治区的卤虫卵最佳孵化盐度为35;用3％双氧水和3％甲醛处理卤虫卵均能提高其孵化率;用粗盐饱和溶液处理是保存卤虫卵的好办法。     

卤虫卵的孵化方法

1.孵化方法 (1)卵的处理市售的卤虫卵一般都比较干燥,在孵化前都要经过一次潮湿冷冻处理。即将干燥的卤虫卵用盐度15‰以上的海水或盐水浸透后,置于-15～-25℃的低温下冷冻30天,然后取出晒干,忌用烈日暴晒,晒干后,密封保存待孵。     

卤虫卵孵化强化剂的初步研究

对不同品系的低孵化率卤虫卵进行了孵化对比试验，分为试验组和对照组，其中试验组添加孵化强化剂与对照组进行同等条件的试验，2组对照组的孵化率分别是66．8％、64．9％，试验组的孵化率分别是84．3％、81．5％增幅超过15个百分点，说明这种针对低孵化率卤虫卵研制的强化剂有效可行，可做进一步推广试验。     

中国卤虫卵孵化特性的研究

本文对山东埕口盐场、海南岛莺歌海盐场及青海柯柯盐湖天然采集的卤虫卵进行了孵化特性研究。埕口、莺歌海及柯柯的虫卵壳厚分别为9.7,11.4及13.2μm。在放入海水中进行孵化前上述三品系的卤虫卵分别在自来水中浸泡2,3及4小时能获得最佳孵化率。它们的最适孵化温度分别为25.6～28.5℃,27.0～30.0℃及27.0～33.0℃。最适孵化盐度分别为30,20及35％。孵化的同步性以“莺歌海”为最好,为6.4小时,“埕口”次之,为6.5小时,“柯柯”为7.4小时。 实验室内培养产卵后24小时内收集的虫卵用下列方法处理能终止虫卵的滞育状态:(1)埕口卤虫卵:浸泡于粗盐饱和溶液中2～3个月,孵化率可达91～94％。(2)莺歌海卤虫卵:浸泡于粗盐饱和溶液中2～5个月,孵化率可达80～91％。(3)柯柯卤虫卵:置于5℃2～3个月孵化率可达96～98％。用3％H_2O_2及3％甲醛溶液处理对终止滞育状态没有作用。天然采集的三个品系的卤虫卵用3％H_2O_2或3％甲醛溶液或用去壳溶液处理均可以提高孵化率。     

孵化卤虫冬卵应注意的问题

卤虫又称丰年虫、鳃足虫或盐虫，孵化卤虫冬卵（以下简称卤虫卵），已成为鱼、虾、压等工厂化育苗过程中极其重要的一个环节。随着水产业的大力发展，卤虫卵供不应求，供需矛盾越来越大，价格不断上涨．因此，提高卤虫卵的孵化率，对育苗效果好坏和生产成本的高低有着直接的影响，为此，介绍孵化卤虫卵应注意的几个问题，供参考、应用。一、严把质且关卤虫卵的质量低下，是造成对化率低的主要原因之一。据Clegg·T·C等（1980）研究指出，刚产的卤虫冬卵，即使在合适的水环境下，孵化事也很低。其原因是某种休眠因子使卵处于滞育状态，必…     

温度、盐度对西藏卤虫卵孵化率的影响

西藏卤虫(Antemia tibetiana)是一种重要的水产资源,其无节幼体是鱼虾幼苗的优质饵料。影响卤虫卵孵化的因素有多种,最重要的是温度和盐度。本文探讨了不同的温度和盐度对西藏卤虫卵孵化率的影响,也进行了光照对孵化率影响的对比试验。结果表明在温度28℃、盐度15时孵化率最高,无光照时会显著降低卤虫卵的孵化率。     

卤虫卵孵化强化剂的生产工艺及应用研究

研制出卤虫卵孵化强化剂及其生产工艺,对天津塘沽盐田和新疆艾比湖的卤虫卵利用孵化强化剂进行了孵化对比试验,分为试验组和对照组,其中试验组添加孵化强化剂,在相同条件下与对照组进行对比试验。结果表明,添加Ⅰ型孵化强化剂的试验组,孵化率平均增幅高达16％,添加Ⅱ型孵化强化剂的试验组,孵化率平均增幅为5％,增幅显著,证明了孵化强化剂具有提高卤虫卵孵化率的功能。     

渤海湾卤虫卵孵化率与盐度关系的试验

采用实验生态学方法,研究了盐度对渤海湾卤虫卵孵化率的影响。试验结果表明,在孵化用水pH8.13~8.21,温度30℃左右,光照250~450lx的条件下,渤海湾卤虫卵在盐度10‰~60‰范围内,均能孵化,盐度40‰、45‰时孵化率最高;盐度20‰~55‰,24h孵化率均在50%以上;盐度75‰时24h孵化率为0,48h孵化率37.5%。建议试验条件下,渤海湾卤虫卵孵化盐度范围控制在25‰~50‰,实际生产中可根据水资源情况在此范围内适当调整。     

盐度、pH及孵化时间对卤虫孵化率的影响

<正> 卤虫早期幼体营养丰富,作为鱼、虾、蟹幼体的饵料,在水产育苗中已被广泛采用,但对其孵化所需盐度、pH及孵化时间意见不一。本文就这几个因子对卤虫孵化率的影响进行了试验总结。 试验用卤虫卵系采自河北省海兴的冬卵。卵取回后经漂洗、沉淀去杂质,在-28～—30℃速冻,存放于-18℃冷库中。用前取     

皱纹盘鲍幼虫流水孵化培育技术的研究

采用紫外线海水培育、充气海水培育、流水孵化培育、流水孵化培育中试4种不同方法进行皱纹盘鲍（Haliotis discus hannai）幼虫孵化培育，并与常规孵化技术对照，结果表明：紫外线海水孵化培育组幼虫48h面盘与壳分离死亡；充气流水培育组幼虫发育畸形；48h下沉死亡；流水培育组幼早孵化率为69.7%，流水培育中试组幼虫孵化率达75.8%。而对照组孵化率仅为23.5%。流水孵化培育不仅提高了孵化率，而且稳定性较高，同时节省大量劳动力。     

Effects of Heavy Metals on the Hatching Rates of Brine Shrimp Artemia salina Cysts

The effects of heavy metals (Hg²⁺, Cd²⁺, Co²⁺, Cr³+, Pb²⁺, Cu²⁺, Fe²⁺. Ni²⁺, Zn²⁺, Mn⁷⁺, Mn⁴⁺ and Mn²⁺) on the relative hatching percentage of brine shrimp, Artemia salina were assessed. Artemia salina cysts (San Francisco Bay Brand) hatched in seawater containing various heavy metal concentrations. After 48 hours, the number of hatched nauplii were counted. A negative linear relationship between hatching rate of Ariemia salina cysts and heavy metal concentration occurred, except copper which conformed to a cubic model. The relative toxicities of heavy metals on Artemia salina cysts were as follows (Cu²⁺, most toxic; Mn²⁺, least toxic): Cu²⁺ > Zn²⁺ > Ni²⁺ > Co²⁺ > Mn⁷⁺ > Cr³⁺ > Cd²⁺ > Fe²⁺ > Hg²⁺ > Mn⁴⁺ > Pb²⁺ > Mn²⁺.     

Hatching and nutritional quality of Artemia cysts progressively deteriorates as a function of increased exposure to hydration/dehydration cycles

Nauplii hatching from Artemia cysts are crucial in larviculture nutrition. Artemia cysts may be exposed to repeated hydration/dehydration (H/D) cycles pre-harvesting or during processing and storage. To observe the effect of these cycles on cyst quality, Artemia franciscana cysts were exposed to a comprehensive set of various H/D treatments, differing in the number of cycles (1, 2, or 3) and the duration of the freshwater hydration period (2 or 4 h). Cyst quality was assessed using the criteria of immediate relevance for aquaculture use, such as hatching percentage directly after H/D treatment and after ?18 °C storage up to 1 month, longevity of axenically hatched starved nauplii, cyst and naupliar energy content, and (for the most extreme H/D treatment) cyst and naupliar fatty acid and vitamin C content. Repeated H/D cycles resulted in significantly (P < 0.05) decreased cyst hatching, reduced starved naupliar longevity and individual energy content, loss in vitamin C and fatty acid content, and moreover a close correlation between these parameters as a function of progressive H/D treatments. This is of immediate relevance for aquaculture nutrition, as commercial Artemia cysts may have gone through an unknown sequence of H/D cycles in nature or in the processing line, which affects the nutritional quality of the nauplii used in larviculture operations.     

PROBIT analysis predicts hatching rates of brine shrimp Artemia sp. cysts

Thirty replicates of San Francisco Bay brine shrimp Artemia sp. cysts from one lot were weighed to 0·01 mg. The mean mass of a single cyst was 2·597 μg (±0·040 μg, 95% confidence level). Batches of 1 g from the same lot were hatched in the laboratory, and fraction hatched versus time data were fitted to a nonlinear curve using PROBIT analysis. Median time of hatch was 24·8 h with a standard error of ±3·92 h. Cysts and nauplii in 1-ml aliquots were pipetted at regular intervals and counted under a dissecting microscope. The number of cysts pipetted at the beginning of the experiment was 19% less than estimates based on the known number per volume of hatching medium, indicating that hatching data derived from pipetting procedures may contain large sampling errors. PROBIT analysis allows fraction hatched to be predicted when a particular lot of cysts is hatched under controlled conditions.     

鮸鱼苗种培育技术试验

经试验18尾亲鱼产卵5.3kg,受精卵经20h孵出,孵化率为63.9%;饵料系列为:轮虫、卤虫、桡足类;经50天培育,育出平均全长33mm幼鱼103万尾,培育成活率23.4%。     

Effects of temperature, salinity, desiccation and chemical treatments on egg embryonation and hatching success of Benedenia seriolae (Monogenea: Capsalidae), a parasite of farmed Seriola spp

The effects of temperature and salinity on the embryonation period and hatching success of eggs of Benedenia seriolae were investigated. Temperature strongly influenced embryonation period; eggs first hatched 5 days after laying at 28 degrees C and 16 days after laying at 14 degrees C. The relationship between temperature and embryonation period is described by quadratic regression equations for time to first and last hatching. Hatching success was >70% for B. seriolae eggs incubated at temperatures from 14 to 28 degrees C. However, no B. seriolae eggs embryonated and hatched at 30 degrees C and <2% of eggs hatched when incubated at 24 degrees C after transfer to 30 degrees C for 48 h. Embryonation period was similar for eggs incubated in sea water at 25, 30 and 35 per thousand salinity, but increased for eggs incubated at higher or lower salinities. When incubated at salinities ranging from 25 to 45 per thousand, more than 70% of B. seriolae eggs embryonated and hatched. Hatching success was lower at 20 and 50 per thousand salinity and few or no eggs hatched at 10 and 15 per thousand. Hatching of B. seriolae eggs can be prevented by desiccation for 3 min, by immersion in water at 50 degrees C for 30 s or by treatment with 25% ethanol for 3 min.     

Quality Evaluation of Four Sources of Brine Shrimp Artemia spp.1

A study was conducted to compare fatty acid composition, hatching quality, and size of nauplii from four commercial sources of brine shrimp (Artemia spp.) cyse: China (CH), Colombia (COL), Great Salt Lake (GSL), and San Francisco Bay (SFB). The CH brine shrimp had a comparatively high percentage of 20:5(n-3) fatty acid (eicosapentaenoic acid or EPA), an essential fatty acid for most Iarval fishes, which was 10.4% of the total lipids. The COL, GSL, and SFB sources of cysts contained comparatively low percentages of EPA, 2.9, 1.2, and 1.6%. respectively. Hatching quality was determined by hatching cysts in salt (NaCl) water with a specific gravity of 1.02 at 27 C for 42 h. The COL cysts had the fastest hatching rate, with 50% of the cysts hatching in 13.4 h, while CH cysts hatched at the slowest rate, requiring 25.6 h for 50% of the cysts to hatch. Total percentage hatch was not significantly different among the SFB, COL, and GSL sources, with an average hatching percentage of 84.5, while CH cysts had a significantly lower total percentage hatch of 67.5. The SFB source produced the greatest number of nauplii (1.6 ± 10⁵ per g of cysts) with the smallest length (382 μm), while CH produced the smallest number (8.7 ± 10⁴) with the greatest length (500 μm). These results indicate that there is great variation in nutritional quality, hatching quality, and size of nauplii among commercial sources of brine shrimp cysts, and each of these criteria should be considered in selecting brine shrimp in a development of a feeding strategy for larval culture of a particular species.     

温度对奥尼罗非鱼受精卵孵化和仔鱼活力的影响

研究了温度对奥尼罗非鱼(Oreochromis niloticus×O.aureus)受精卵孵化和仔鱼活力的影响。在盐度为5不同温度(22、24、26、28、30、32和34℃)下,比较观察奥尼罗非鱼受精卵的培育周期、孵化周期、孵化率和畸形率。同时在以上不同温度条件下对初孵的奥尼罗非鱼仔鱼进行耐饥饿试验,测定其不投饵存活系数(Survivalactivity index,SAI)。结果表明:在温度为24~32℃,受精卵孵化率较高(84.3%~91%),温度高于34℃和低于22℃时,孵化率较低。温度与培育周期呈负相关关系,函数关系为y=0.3607x2-26.836x+553.5,R2=0.973。仔鱼生存适宜温度是24~30℃,最适的温度是24~26℃。温度为22℃时,SAI值分别为19.9,但是仔鱼发育的缓慢,部分仔鱼的身体色素一直没有出现,不适合仔鱼的培育。     

盐度对棘头梅童鱼胚胎发育和仔鱼存活的影响

观察比较了11个盐度梯度[0、5、10、15、20、25、30(自然海水)、35、40、45、50]下,棘头梅童鱼(Collichthys lueidus)胚胎的沉浮情况、孵化时间、孵化率和畸形率,并测定了初孵仔鱼的不投饵存活系数(SAI)。结果表明:(1)棘头梅童鱼胚胎在海水盐度为30及以上时100%漂浮;盐度为25时,95%漂浮,5%悬浮;盐度为20时95%悬浮,5%沉底;盐度为15时95%沉底,5%悬浮;盐度为10及以下时100%沉底。在水温18～20℃的条件下,棘头梅童鱼胚胎在盐度5～40范围内经28～32 h能孵化出仔鱼,盐度对孵化时间影响不显著(P>0.05)。但孵化率和畸形率因盐度不同而有显著差异。综合分析表明棘头梅童鱼胚胎孵化的适宜盐度范围为15～35,孵化最适盐度范围在20～30之间。(2)在可孵出鱼苗盐度范围(5～40)内,棘头梅童鱼仔鱼SAI值为(1.80±0.03)～(11.85±0.02),与卵的孵化率呈正相关关系。仔鱼生存的适宜生长盐度为10～30,最适盐度范围为20～25。