经济海藻资源的开发利用

海藻是重要的海洋资源 ,大型海藻如褐藻、红藻和绿藻中的许多种类都具有很高的经济价值。经济海藻主要的栽培和消费国家是中国、日本和韩国等 ;在日本 ,紫菜、裙带菜、海带等海藻已成为传统食品中不可缺少的部分。海藻的栽培、加工是这些国家海水养殖的重要内容。其它亚洲国家及欧美各国都有丰富的海藻资源并得到了广泛利用。1　海藻资源的利用海藻种类繁多 ,资源丰富。海藻资源的利用主要包括海藻胶、海藻食品、海藻饲料、海藻肥料等方面的生产利用。1 .1海藻胶工业海藻胶的生产是海藻工业的主体 ,其中的琼胶、卡拉胶和褐藻胶等的加工和市…     

印度尼西亚海藻养殖产业概况

印度尼西亚是重要的渔业大国,是我国渔业"走出去"和渔业科技国际合作的重要伙伴。印度尼西亚的海藻养殖产量位居世界第二,是海藻胶加工原料的重要出口国,其产卡拉胶海藻约有70%出口中国。文章介绍了印度尼西亚海藻养殖产业的相关概况,包括养殖海藻的品种、产量、分布、养殖技术、收获、初加工和贸易等,旨在梳理印度尼西亚海藻养殖产业发展的历史、现状及前景,为我国海藻养殖产业的发展提供借鉴,也为我国与印度尼西亚开展海藻产业领域方面的合作提供背景资料。     

马尾藻池塘人工养殖技术初步研究

马尾藻(Sargassum)属的种类是广东省的重要经济海藻,通常被用作饲料、藻胶和医药工业的原料,也可用作海藻肥料、饲料添加剂等。近几年来,随着人们对马尾藻应用研究的不断深入,愈来愈多的人认识到马尾藻的经济价值,一些企业对马尾藻的需求逐年增大,同时,由于受到近海采捕、港口建设、采集贝类等因素的影响,马尾藻的自然资源量在不断的下降,从而造成马尾藻的供需矛盾不断加剧。因     

浅议中国海藻开发利用

中国有绵长的海岸线，广阔的浅海区，已报道的海藻种类的800种，其中有直接经济价值的种达百种之多，目前，海带、裙带菜、紫菜、江蓠和麒麟菜等已成为大农业范畴的栽培种类，不论是规模，还是产量都有很大发展，但养殖技术尚有待改进，许多其它经济种类尚未得到很好的开发利用，为进一步提高和改善已养种类的养殖技术，加强对新经济种类的开发利用，本文从食用海藻，饲料海藻，藻胶海藻，美容保健海藻，药用海藻，农用海藻和单细胞海藻等方面对中国海藻的开发利用提出了一些肤浅建议。     

裙带菜配子体和孢子体的形态

裙带菜[Undaria pinnatifida(Harv．)Suringar]属褐藻门褐子纲海带目(Laminarimes)翅藻科(Alariaceae)，是重要的经济海藻之一，在我国舟山群岛、嵊泗列岛、青岛、烟台、大连等地都有其自然分布。裙带菜是一种有明显世代交替的一年生海藻。     

筛选良种发展江蓠种植业

随着海藻工业的发展和藻胶加工技术的提高，江 已成为国内外提取琼胶的主要原料。它们广泛分布在热带、亚热带的浅海滩涂和鱼 、水塘中。广东、海南、广西等省沿海，不但品种多，而且资源也很丰富，具备开展江苗人工种植的自然条件。据中国科学院海洋研究所张峻甫，     

海草床的固碳潜力及其生物量监测方法研究进展

<正>海洋是地球上最大的活跃碳库,包括浮游生物、细菌、海藻、海草床、盐沼和红树林等在内的海洋生态系统固定了全球50%以上的碳,每年可吸收约30%的人类活动排放到大气中的CO₂,其碳储量分别是陆地碳库和大气碳库的20倍和50倍,是地球上最高效的碳汇,在应对全球气候变化、保护生物多样性和实现可持续发展等方面发挥着重要作用^[1]。     

海藻对人类健康促进作用的研究进展

<正>海藻以其特殊的营养成分和特点,富有的营养价值和药用价值对人类健康产生了巨大的促进作用,生态修复的环境价值也逐渐发挥出重要作用。本文综述了海藻的食品应用、药用和保健作用、生态修复作用等方面对人类健康的促进作用以及目前国内外对海藻的应用研究进展。     

试析福建海藻食品工业的发展潜力

海洋经济藻类在食品工业、医药卫生、能源以及其它化学资源方面有着广泛的应用。我国海藻资源极为丰富,海带和裙带菜产量居世界首位,紫菜产量仅次于日本。位于亚热带的福建近海是我国商品海藻的主要产区,海带产量占全国总产量的20％,仅次于山东和浙江。紫菜产量则占全国总产量的80％。其它海藻如裙带菜、浒苔资源也相当丰富。福建海藻食品加工业(包括海藻胶工业及原藻食品加工业)在技术和生产设备方面已具有一定的基础,潜在着广阔的发展前景。但近年来,除了在紫菜琼脂业方面有着较显著的发展外,就海藻食品工业总体而论,发展步伐还较缓慢,其现状与我省海藻资     

怎样区别琼指和卡拉胶

《海南日报》曾发表过一篇文章,文中错将卡拉胶当成琼脂。据了解,这种情况在海南以至各地还比较普遍。其实,卡拉胶和琼脂是两种不同的海藻胶,不能混为一谈,否则,将会给生产或销售造成损失。所以,笔者想谈谈两者的区别。琼脂(又名琼胶,冻粉),与卡拉胶、褐藻胶合称三大海藻胶。琼脂和卡拉胶都是从海藻中提取出来的胶     

Rare serotype occurrence and PFGE genotypic diversity of Streptococcus agalactiae isolated from tilapia in China

Previously, we reported 10 PEGE types of 85 tilapia Streptococcus agalactiae(GBS), which shifted from Streptococcus iniae in China, by using PEGE method. Presently, larger and more representative tilapia GBS were isolated, for the ?rst time in China, to characterize their serotypes and genetic diversities more precisely than had done before. 168 GBS strains were distributed in ?ve provinces of China, in which Guangdong, Guangxi and Hainan were the major ones, holding36.9%(62/168), 37.5%(63/168) and 19.6%(33/168), respectively. Serotypes, Ia, Ib and III, were observed in these strains and the most predominant one was Ia(95.2%), which mainly distributed in Guangdong, Guangxi and Hainan. Ia initially occurred in 2009, it shoot up to 32.1% in 2010,but decreased to 16.1% in 2011 before went up to 45.2% in 2012. Ib sporadically occurred during2007–2011, III onlyoccurred in 2012. 14 different PFGE types, including 4 new types(N, O,P and Q), were observed, in which B, D, F and G were the predominant types, holding 83.9%(141/168) of the total GBS strains. Ia corresponded to 11 PFGE types(A–H, N–P), in which type D predominated(51%). Ib represented 3 genotypes(I, J and Q) and III harbored only 2genotypes(N and F). Type N and Fsynchronously presented in Ia and III. In summary, the genetic diversity of tilapia GBS varied by serotypes and changed with geographical locations and years.Although Iastillpredominated, new rareserotypeIII alreadyoccurred in China.     

Growth hormone (GH) and reproduction: a review

Interaction between growth and reproduction occurs in many vertebrates and is particularly obvious at certain stages of the life cycle in fish. Endocrine interactions between the gonadotropic axis and the somatotropic axis are described, the potential role of GH being emphasised. A comparative analysis of these phenomena in mammals, amphibians and fish, suggests a specific role of GH in the physiology of puberty, gametogenesis and fertility. It also shows the original contribution made by studies on the fish model in this field of investigations.     

Purification and partial characterization of GtHs (cfLH and cfFSH) from Indian walking catfish (Clarias batrachus) (L.) and development of a homologous ELISA for cfLH

Two gonadotropins (GtH; Qa and Qb) were purified by gel filtration and ion exchange chromatography from the pituitaries of Indian walking catfish (Clarias batrachus). The presence of GtH during purification was assessed by in vitro oocyte maturation and in vivo steroidogenic activity, and their identities were determined by elution profiles, molecular weight, biological activities and yield. The molecular weights of Qa and Qb were 37 and 42 kDa, respectively, and composed of distinct subunits (Qa: 20 and 14 kDa and Qb: 26 and 18 kDa). Polyclonal antibodies raised against Qa immunostained Qa, Qb and pituitary GtH cells. A competitive Qa‐ELISA was developed whose sensitivity was 6.25 ng mL^?1 (1.25 ng well^?1) with intra‐ (3.5%) and inter‐ (12.4%) assay coefficients of variation. Displacement curves parallel to the standard were obtained with plasma and pituitary extracts of catfish, Qb and carp GtHII. The assay was validated by measuring the plasma Qa levels after LHRH treatment and in relation to ovarian growth in the female catfish during different reproductive phases. Based on the results, Qa and Qb corresponded to fish LH and FSH respectively. The findings will increase the knowledge of the mechanisms controlling fish reproduction and identification of sensitive phases in fish in captivity for hormonal manipulation.     

Controlled infection of Poecilia reticulata Peters (guppy) with Tetrahymena by immersion and intraperitoneal injection

Tetrahymena is a protozoan parasite, which infects guppy, Poecilia reticulata Peters, and causes substantial economical losses in commercial farms worldwide. Studies of guppy infected by Tetrahymena require standardized infection protocols. The LD50 for Tetrahymena infection of guppies by intraperitoneal (IP) injection was calibrated, and the level obtained was 946 parasites per fish. Guppy infection with Tetrahymena by immersion, imitating the natural route of infection via the integument, was studied under normal or stress conditions. Exposure to cold and netting (CNI) and to cold only (CI) followed by immersion exposure to 10 000 Tetrahymena per mL resulted in 22.5% and 19.2% mortality, respectively, as compared to 14.2% and 10% in groups that were netted only (NI) or non‐stressed (I). Histopathology revealed that immersion infection resulted in a systemic infection. Lysozyme levels, measured 3 weeks after infection, were significantly higher in the CNI group (288 μg per mg protein) compared with CI‐, NI‐ and I‐treated groups (94.5, 64 and 62.3 μg mg^?1, respectively). There was no evident parasite immobilization activity in body homogenates, suggesting no development of acquired immunity. Re‐infection by IP injection revealed no increase in protection in any of the treatment groups, mortality range of 56.3–75%, higher than in the non‐exposed control (40.6% mortality).     

Evaluation of a Fast Method Based on the Presence of Two Restriction Sites in the Mitochondrial ND5 (mt ND5) Gene for the Identification of Scomber Species

The purpose of this work was to evaluate the suitability of a method based on the presence of two restriction sites (for Hae III and Hindf I) in the mitochondrial NADH dehydrogenase subunit 5 (mt ND5) gene to identify Scomber species. The evaluation was performed on 144 reference and market samples by sequencing of the entire 505-bp fragment of the mt ND5 gene and of a 464-bp fragment of the Kocher fragment of the cytochrome b gene (mt Cytb). Sequence analysis of any of the two fragments allows the identification of each of the four Scomber species, but S. japonicus and S. colias had the same restriction sites at the ND5 amplicon and would not have been differentiated by this analysis. Similarly, loss of the Hae III site in some S. scombrus individuals would have misidentified them as not being Scomber. All the market products were correctly labeled except one acquired in Spain labeled as originating in the Atlantic and containing S. japonicus.     

Imported ornamental fish are colonized with antibiotic‐resistant bacteria

There has been growing concern about the overuse of antibiotics in the ornamental fish industry and its possible effect on the increasing drug resistance in both commensal and pathogenic organisms in these fish. The aim of this study was to carry out an assessment of the diversity of bacteria, including pathogens, in ornamental fish species imported into North America and to assess their antibiotic resistance. Kidney samples were collected from 32 freshwater ornamental fish of various species, which arrived to an importing facility in Portland, Oregon from Colombia, Singapore and Florida. Sixty‐four unique bacterial colonies were isolated and identified by PCR using bacterial 16S primers and DNA sequencing. Multiple isolates were identified as bacteria with potential to cause disease in both fish and humans. The antibiotic resistance profile of each isolate was performed for nine different antibiotics. Among them, cefotaxime (16% resistance among isolates) was the antibiotic associated with more activity, while the least active was tetracycline (77% resistant). Knowing information about the diversity of bacteria in imported ornamental fish, as well as the resistance profiles for the bacteria will be useful in more effectively treating clinical infected fish, and also potential zoonoses in the future.     

Effect of iodophor disinfection of non‐hardened Salmo trutta eggs on their bacterial and fungus load

This study investigated the efficiency of iodophor disinfection (135 ppm active iodine for 15–30 min) of non‐hardened Salmo trutta eggs against different groups of bacteria and against fungus. Egg samples were taken from non‐disinfected and from disinfected eggs, microorganisms were cultured on specific nutrient media and their mass was measured by turbidimetric methods. Bacteria and fungus mass of non‐hardened eggs could be reduced but not eliminated by iodophor disinfection with 135 ppm active iodine for 15 min. The extent of reduction was 47–65% (Experiment 1). The efficiency of disinfection increased with disinfection time as the reduction in bacteria and fungus mass was 40–55% after 15 min and 58–74% after 30 min (Experiment 2). Disinfection efficiency of iodophor solution diluted in water (reduction 49–57%) and of iodophor solution diluted in sodium chloride solution iso‐osmolar to the oocytes (reduction 52–61%) was similar (Experiment 3). The reduction in bacteria and fungus mass was persistent as it was 39–72% lower in embryos deriving from disinfected eggs than in embryos deriving from non‐disinfected ones (Experiment 4). In conclusion, the tested disinfection method is inadequate to eliminate pathogens completely but it could positively influence immune defence of eggs and embryos.     

Nitrogenous waste excretion and accumulation of urea and ammonia inChalcalburnus tarichi (Cyprinidae), endemic to the extremely alkaline Lake Van (Eastern Turkey)

The endemic, anadromous cyprinidChalcalburnus tarichi is the only fish species known to occur in alkaline Lake Van (Eastern Anatolia, Turkey). EightC. tarichi were maintained individually in Lake Van water (17 – 19°C; pH 9.8; 153 mEq·I^–1 total alkalinity; 22 total salinity) and tank water samples analyzed for 24 h in 2 to 4 h intervals. At zero time, < 1µM ammonia was present and urea was undetectable in the tank water; at 24 h, total ammonia and urea made up 114±32 and 35±25µM, respectively. Over the experimental period, ammonia-N and urea-N excretion averaged 1041±494 and 607±169moles·kg^–1 fish·h^–1, respectively. The extent of urea excretion was highly variable between specimens. Uric acid excretion was not detectable.Urea was present at high concentrations in all tissues and plasma (25 – 35moles·g^–1·ml^–1) of freshly caughtC. tarichi; total ammonia content of the tissues was by a factor of 1.9 (liver) to 3.0 (brain) lower. High arginase activity (2.4±0.2 U·min^–1·g^–1) was detected in the liver ofC. tarichi but ornithine carbamoylphosphate transferase, a key enzyme of the ornithine-urea-cycle, was absent. Ureagenesis is likely through degradation of arginine and/or uricolysis. High glutamine synthetase activity (11±0.6 U·min^–1·g^–1) and low ammonia content in brain suggest that, like other teleosts,C. tarichi has an efficient ammonia detoxification in the brain, but in no other tissue.Nitrogenous waste excretion at alkaline pH is discussed. The ability ofC. tarichi to excrete high levels of ammonia at extremely alkaline pH is unique among teleosts studied so far. The mechanism of ammonia excretion under Lake Van conditions remains to be elucidated.