丰年虫卵孵化前的预处理

丰年虫卵孵化前的预处理丰年虫是仔虾特别重要的饵料。自然孵化的丰年虫不能适应人工养虾的需要。人工孵化丰年虫，应在孵化前对丰年虫卵进行脱膜和消毒处理。一、丰年虫卵的脱膜方法丰年虫卵具有很厚的卵壳，经脱膜处理可提高丰年虫卵的孵化率，还能起到消毒作用，减少谈...     

丰年虫卵质量的鉴定

1 质量鉴定的主要内容1.1 孵化率一般来讲，丰年虫卵孵化率在90％以上的为A级，70％以上的为C级。1.2 每克卵的粒数进口丰年虫卵每克的粒数，A级一般为27万～29万粒，C级为23万粒左右。如水分和杂质含量高，每克粒数相应减少。1.3 含水率进口丰年虫卵的含水率A级为6％～7％，C级7.3％左右。国产丰年虫卵的含水率上下幅度较大。1.4 杂质含量进口丰年虫卵的杂质含量一般为0.3‰左右，而国产丰年虫卵的杂质含量上下幅度也较大。2 质量鉴定方法2.1 孵化率的测定步骤a.随机取样并拌匀，取100粒为1份，共取6份，分别放入培养皿中；b.在培养皿中…     

用古根丰年虫幼体培育黄颡鱼鱼苗试验

分别用古根丰年虫幼体和水溞培育黄颡鱼鱼苗,结果表明,投喂古根丰年虫鱼苗的生长速度和成活率均明显优于摄食水渣的黄颡鱼龟苗,培育每万尾黄颡鱼苗约需古根丰年虫卵280 g.     

乌贼内壳中β-壳聚糖的制备研究

本文研究了用乌贼内壳制备β-甲壳素和壳聚糖,结果乌贼内壳背楯提取甲壳素的最佳条件为:先用1.5 mol/L HCl浸24 h,再用1.5 mol/LNaOH于80℃浸3 h。产率为3.55％。从乌贼内壳周缘提取甲壳素的最佳条件为:先用1.5 mol/LHCl浸24 h,再用1 mol/L NaOH75℃浸3 h,产率为30％;产品用IR和XRD表征。实验结果还表明,加入相转移催化剂可提高β-壳聚糖的脱乙酰度。     

购买丰年虫卵时的“望闻问切”

近年来丰年虫卵的需求量逐渐增大,价格迅速上扬。有些销售者乘机以次充好,使不少生产单位上当受骗,遭受了经济损失,也影响了育苗生产。现介绍一个检查丰年虫卵质量的简易方法:望——目测卵的色泽,以棕褐色、有光泽、纯净者为好;在烧杯中加水,放入一些卵,轻轻摇晃,如果水变混或有微小颗粒     

卤虫卵壳营养成分分析

采用一般营养物质测定方法及液相色谱和气相色谱方法测定了卤虫卵壳营养成分。结果表明:蛋白质58.91％,脂肪5.63％,灰分8.92％;17种氨基酸总量为干物质的57.73％,必需氨基酸含量占氨基酸总量的36.60％;卤虫卵壳含有多种不饱和脂肪酸,其中EPA占8.54％;卤虫卵壳含有多种无机元素,其中钙为13865.23μg/g,铁为9928.17μg/g。卤虫卵壳含有丰富的营养成分,因此可将其开发为营养强化剂或其它动物饲料。     

新疆艾比湖丰年虫资源动态研究

<正>丰年虫是艾比湖重要的经济种类,了解和掌握艾比湖丰年虫资源开发状况对确保其可持续利用具有重要意义。本文通过对艾比湖丰年虫群体结构变动及生长、生殖等调查研究,了解艾比湖丰年虫的世代交替变化规律、丰年虫种群数量和丰年虫卵数量变动规律,通过建立数学模型,对艾比湖丰年虫生产能力与丰年虫卵资源量进行估算。结果表明:2015年5月～10月艾比湖丰年虫总生产量、总产卵量及未孵化滞育卵总量分别为11242吨,1329吨及1304吨。研究结果为日后艾比湖丰年虫资源养护、管理、利用等方面的政策、规划提供科学依据。     

土法加工丰年虫卵的工艺及技术要点

<正> 丰年虫(卤虫)是鱼虾蟹等水产动物育苗的最佳开口饵料,也是水产养殖必不可少的生物饵料。一般育苗室年需丰年虫卵一吨多,需求量很大。全国沿海育苗单位丰年虫卵几乎都依赖进口,目前,进口卵价格昂贵,货源紧张,缺口很大,致使假冒伪劣产品泛滥,影响了育苗及养殖生产的发展。 乐亭县濒临渤海,海岸线长达98.25千米,海水含盐量高,适应盐业开发建设。县境已有大清河盐场为主的5个大小盐场。水汪、蒸发池、蓄水池蕴藏着丰富的丰年虫(卤虫)资     

超声波法制备高黏度的壳聚糖

以甲壳素为原料,用超声波法制备高黏度的壳聚糖。研究超声波的温度、超声的时间以及制备壳聚糖时浓碱的浓度3个不同条件对壳聚糖黏度的影响。结果表明,用超声波制备高黏度壳聚糖的最佳反应条件是:反应温度为50℃,反应时间为3 h,NaOH溶液的浓度为50%,可以得到黏度为2886.7mpa.s、脱乙酰度达97.17%的壳聚糖。将得到的高黏度壳聚糖制成膜,用于染料废水的处理,15 h后,壳聚糖膜对活性橙的脱色率就可达到99.5%。     

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。     

Extraction of Chitin from the Shell Wastes of Two Shrimp Species Fenneropenaeus semisulcatus and Fenneropenaeus indicus using Microorganisms

Traditionally, chitin is extracted from crustacean shells using chemical methods involving the use of strong acids and alkali. In this study, chitin was extracted from the shrimp shell waste using microbes isolated from the fermented milk and bread. The chitin yield from the shells of Fenneropenaeus semisulcatus was 14.054% and 16.062%, respectively, for shell:bacterial broth ratios of 1:15 and 1:25; whereas, the yield of chitin from the shells of Fenneropenaeus indicus was 14.93% and 13.871%, respectively, at 1:15 and 1:25 broth ratios. The Fourier transform infrared spectra obtained from the chitin samples showed characteristic chitin peaks in both shell to bacterial broth ratio. The X-ray diffraction analysis revealed peaks between 10–15 and 25–30 degrees in the chitin recovered from both species, though some variations between species were observed. In conclusion, results of the present study indicate that application of microorganisms for the extraction of chitin from the shrimp shell waste could be an alternative for the traditional chemical methods.     

甲壳素、壳聚糖生产工艺研究

本文以虾壳为原料探讨了甲壳素、壳聚糖的最佳提取工艺。试验中利用稀氢氧化钠溶液除去虾壳中的粗蛋白质,稀盐酸溶液除去虾壳中的灰分,并通过单因素试验得出制备甲壳素的最佳工艺条件为:先用5.0%氢氧化钠溶液脱粗蛋白质,处理时间5h,然后用5.0%盐酸溶液脱灰分,处理时间3h,循环处理直至加酸无气泡产生,甲壳素得率为6.0%,色泽白度为50.3,灰分为2.0%。通过正交试验探讨出甲壳素脱乙酰制备壳聚糖的最佳条件为:氢氧化钠溶液浓度50%,温度90℃,时间12h,料液比1∶70。壳聚糖脱乙酰度(D.D%)为84.8%,粘度(浓度1%)为38.3mPa.s。     

Comparison of Lactic Acid Bacteria Fermentation with Acid Treatments for Chitosan Production from Shrimp Waste

The traditional procedure for chitosan production involves use of a strong acid (HCl) for demineralization of chitin. This study reports application of a mixed culture of lactic acid bacteria (Lactobacillus plantarum, Lactobacillus acidophilus, and Lactobacillus lactis) fermentation in demineralization of chitin for chitosan production from shrimp waste. Chitosan produced from shrimp waste with lactic acid bacteria fermentation at 30°C for 72 h or 1 M lactic acid treatment at room temperature for 2 h followed by alkaline treatments (0.5 M NaOH at 25°C for 4 h followed by 12.5 M NaOH at 70°C for 10 h) contained very low protein (0.8–1.1%) and ash (<0.01%) contents with the same solubility (100%) as those of chitosan produced with hydrochloric acid treatment. Lactic acid bacteria fermentation and lactic acid treatment may be utilized in chitosan production from shrimp waste to reduce use of strong chemicals.     

Fatty acid analysis of fish eggs without solvent extraction

Two techniques for preparing samples of Coryphaena hippurus fish eggs for fatty acid analysis were compared. The first technique involved direct methylation of samples containing either 50 or 100 fresh eggs. The second involved methylation of the solvent-extracted fat from samples containing 1000 eggs each that had either been freeze dried or oven dried. The fatty acid profiles of small samples of fresh eggs were similar to profiles obtained from the solvent-extracted fat of much larger samples of dried eggs. In addition, the fatty acid profiles of 100 fresh egg samples were higher in both saturated and unsaturated fatty acids than the profiles obtained from 100 freeze-dried or oven-dried eggs. The technique of using direct methylation of fresh egg samples without solvent extraction has three main advantages: it requires less preparatory and analytical work, it can be used with much smaller samples, and it is less destructive to the material being analyzed. Direct methylation can also be used to prepare samples of small organisms such as algae, rotifers (Brachionus sp.), and brine shrimp (Artemia sp.) for fatty acid analysis.     

Effects of dietary chitosan on growth,survival and stress tolerance of postlarval shrimp,Litopenaeus vannamei

The effect of chitosan, a polymer of glucosamine obtained by the deacetylation of chitin, on growth, survival and stress tolerance was studied in postlarval Litopenaeus vannamei. An experiment was performed with postlarval shrimp (mean initial wet weight 1.2 mg) fed five isoenergic and isonitrogenous diets containing five supplemented levels of chitosan (0, 0.5, 1, 2 and 4 g kg^?1 diet, respectively). The five compound diets (C0, C0.5, C1, C2 and C4) sustained shrimp growth throughout the experiment. Growth performance (final body weights; weight gain; SGR: specific growth rate) in shrimp fed diet C2 was significantly higher than that in shrimp fed diets C0, C0.5 and C1 (P < 0.05), diet C4 treatment provided intermediate growth result. The survival in shrimp fed diet C1 was significantly higher than that in shrimp fed C0 diet (P < 0.05), other diets treatments gave the intermediate survival results. No significant differences were found in growth and survival between diet C2 and C4 treatments. After 9 days of a stress tolerance test, survival in shrimp fed diets C1, C2 and C4 was significantly higher than that in shrimp fed diets C0 and C0.5. We concluded from this experiment that the incorporation of a moderate dietary chitosan was beneficial to the development of postlarval L. vannamei. Considering the effect of chitosan on both growth and survival of postlarval L. vannamei, second‐degree polynomial regression of SGR and survival indicated optimum supplement of dietary chitosan at 2.67 and 2.13 g kg^?1, respectively, so the level of chitosan supplemented in the diet should be between 2.13 and 2.67 g kg^?1.     

Technological improvements for the cultivation of invertebrates as food for fishes and crustaceans. II. Hatching and culturing of the brine shrimp, Artemia salina L.

Although extensive fundamental research has been performed on the brine shrimp, the yields from hatching and culturing this organism which is widely used in mariculture, can be greatly improved. By exposing the immersed cysts to light and by using a new type of hatching cylinder and separator box, greater hatching and separation efficiencies can be obtained. Controlled mass culture of brine shrimp larvae to the adult stage has been extremely difficult until now; the literature on the subject is reviewed and a new tech-nique of high density culturing at the pilot-stage is described.     

Using brine shrimp as a drug carrier for therapeutic applications in aquaculture

A method is described to introduce water-insoluble drugs into brine shrimp nauplii (BSN). The uptake of drug by brine shrimp may be modeled as a batch adsorption process; in this way, one can calculate the dosage required for a given population of BSN. The results of this study show that a drug can be loaded into BSN at concentrations up to 9 μg per nauplius. Such concentration is high enough to fulfill the recommended dosage for an adequate treatment of BSN-feeding fish or shrimp larvae. Results are also presented on the loss of drug upon the transfer of larvae from medicated water to drug-free water.     

Explanation of Size Diversity Among Artemia Cohorts: A Model of Food Uptake Kinetics

Models describing the food uptake kinetics of a growing Artemia culture and the hatching rate of Artemia cysts are combined to yield equations capable of predicting the effects of variable algal cell concentration upon the growth rates of brine shrimp cohorts. The model illustrates that the feeding ability of the brine shrimp can be viewed as one becoming increasingly more efficient as the animals mature. This increasing efficiency in a population of variable age animals (from a single hatch) results in accelerated growth of first hatched animals relative to later hatched animals, especially at algal cell concentrations below certain threshold values. Growth rates of variable age groups of brine shrimp are mathematically manipulated to predict variable size brine shrimp at low algal cell concentration and uniformly sized brine shrimp at high algal cell concentration. This predicted result is confirmed with data from Artemia growth trials at high and low algal cell concentrations. It is suggested that similar variations in population attributes of other species may be explained as an animal-food interaction in which minor initial variations in individual animal maturity (weight, size, etc.) are magnified as a consequence of continuous competition for a common pool of food.     

Cellulase degradation of shrimp chitosan for the preparation of a water-soluble hydrolysate with immunoactivity

ABSTRACT:   Samples of colloidal chitin and chitosans with deacetylation degrees (DD) of 50, 65, 75 and 95% (DD50, DD65, DD75 and DD95, respectively) were prepared from shrimp chitin. The hydrolytic activity of cellulase on these samples increased with the increasing DD of chitosan, with DD95 being the most easily hydrolyzed. Colloidal chitin was hardly hydrolyzed. The optimal reaction temperature and pH for cellulase digestion of chitosan were 55°C and pH 5.2, respectively. During cellulase digestion of chitosan, the 9-h hydrolysate had the highest enhancing effect on the proliferation of a human hybridoma cell, HB4C5. This hydrolysate is composed of low-molecular-weight chitosan (LMWC), with a molecular mass of 20.0 kDa, and chitooligosaccharides, which are composed of sugars with a degree of polymerization of 1–6. In vitro , the 9-h hydrolysate increased both cell proliferation and immunoglobulin (Ig)M secretion of HB4C5 because of the presence of chitooligosaccharides for the former activity and LMWC for the latter activity. In vivo , samples of the chitosan hydrolysate, chitooligosaccharide mixture and LMWC significantly increased the levels of serum IgG and IgM, and enhanced concanavalin A- and lipopolysaccharide-induced proliferation of mouse lymphocytes.     

摇瓶法测定卤虫卵的孵化率

作者设计一种摇瓶法与目前国内常用的烧杯法对同一卤虫卵样品进行孵化率测定，其平均值分别为８４．８５％和８０．９０％，前者显著高于后者。两种方法比较，摇瓶法的测定结果更准确。