杂交鳢及其亲本血清蛋白和甘油三酯含量的比较分析

研究采用全自动生化分析仪,检测并比较杂交鳢(乌鳢♂×斑鳢♀)及其亲本血清蛋白及甘油三酯含量的异同.结果显示,在总蛋白(TP)和白蛋白(ALB)的含量上,杂交鳢均与其父本(乌鳢)无显著性差异,与其母本(斑鳢)有显著性差异(P＜0.05);在高密度脂蛋白(HDL)含量上,杂交鳢则与其父本(乌鳢)有显著性差异(P＜0.05)...     

配合饲料养殖月鳢试验

月鳢 (Ｃｈａｎｎａａｓｉａｔｉｃａ)是鳢科鱼类的一种 ,其价格高于乌鳢 4～ 6倍 ,已成为开发养殖的新品种。目前对鳢科鱼类的研究多集中在乌鳢 ,而对月鳢的研究仅限于一般生物学特性、人工繁殖、养殖等 ,还未见有关月鳢营养及配合饲料方面的研究报道。月鳢属于动物食性的鱼类 ,目前养殖多用动物鲜活饵料如小鱼、河蚌、蚯蚓等 ,由于动物饵料缺乏 ,一定程度上限制了月鳢养殖的发展。为此 ,我们 1 996～ 1 999年在进行月鳢生物学习性、人工繁殖研究的基础上 ,进行了月鳢配合饲料的研制 ,并进行了用配合饲料饲养月鳢的养殖试验 ,报道如下。1　…     

配合饲料养殖月鳢试验

月鳢(Channa asiatica)是鳢科鱼类的一种,其价格高于乌鳢4～6倍,已成为开发养殖的新品种.目前对鳢科鱼类的研究多集中在乌鳢,而对月鳢的研究仅限于一般生物学特性、人工繁殖、养殖等,还未见有关月鳢营养及配合饲料方面的研究报道.月鳢属于动物食性的鱼类,目前养殖多用动物鲜活饵料如小鱼、河蚌、蚯蚓等,由于动物饵料缺乏,一定程度上限制了月鳢养殖的发展.为此,我们1996～1999年在进行月鳢生物学习性、人工繁殖研究的基础上,进行了月鳢配合饲料的研制,并进行了用配合饲料饲养月鳢的养殖试验,报道如下.     

乌斑杂交鳢

正鳢科鱼类是我国重要优质淡水鱼类,产量高、肉质好,无肌间刺,药用价值高,经济效益好,在民间深受青睐。近年来养殖产量稳步增长,2014年已超过51万吨,为淡水鱼类第8大品种,在优质鱼类排名第一。我国鳢科鱼类主要包括乌鳢、斑鳢及月鳢等,养殖品种以乌鳢、斑鳢以及斑乌杂交鳢(斑鳢为母本、乌鳢为父本)为主,但每个品种都有其无法忽略     

月鳢成鱼养殖技术

月鳢成鱼养殖技术月鳢是分布于我国长江以南山区和丘陵水域的淡水名贵经济鱼类，俗称星光鱼、七星鱼、秤星鱼等，分类地位上与乌鳢同属鳢科，但不同属。月鳢成体的可食率高（达７５．６％），肌肉蛋白含量高于一般鱼类，具有治湿痹、祛风湿、养阴补血、促伤口愈合等药用价...     

斑鳢与乌鳢血液生理生化指标的比较分析

采用K-4500型血细胞分析仪和OLympus Au400生化分析仪及参照人的血液性状分析法,测得斑鳢的红细胞(3.27±0.54)1012/L比乌鳢(3.71±0.51)1012/L的低,平均红细胞体积(128.5±3.62)fl比乌鳢(124.05±3.06)fl的高。血红蛋白(148.7±9.33)g/L含量比乌鳢(115.0±7.25)g/L高,斑鳢的细胞脆性比乌鳢的小。生化指标中斑鳢除血糖含量比乌鳢大外,血清总蛋白含量(37.30±4.06)g/L、白蛋白含量(21.67±3.39)g/L、血清中甘油三酯的含量(0.53±0.06)mmol/L、胆固醇(4.37±0.68)mmol/L都比乌鳢低。分析表明斑鳢的活动性、抗病力比乌鳢的强。     

乌鳢及鳢科鱼类染色体组型的比较研究

研究了乌鳢的染色体组型，分析了与月鳢、斑鳢染色体组型的不同。结果表明：乌鳢的染色体数目为2n=48，核型公式为：4sm 22st 22t，最大染色体组位于st组。讨论了鱼类核型演化过程中的增加双倍染色体的倾向，具有较多t染色体的是较原始的种类，而具有较多m、sm染色体的种类是特化种类，即染色体臂数较多的为进化类型。比较3种鱼类的染色体特征，发现乌鳢的NF最多(68)，sm染色体数也高于其它种类，说明鳢科谱系分类上的位置中，乌鳢的进化程度较高，适应性强，月鳢次之，斑鳢最原始。     

斑鳢养殖技术

鳢科鱼类在我国只有3种:乌鳢、斑鳢、月鳢。斑鳢(Channa maculata)主要分布于长江流域以南地区,如广东、广西、海南、福建、云南等省区。斑鳢(广东俗称本地生鱼)同乌鳢(广东俗称湖南生鱼)相比较,味道香浓,腥味少,鱼肉嫩滑,商品价值高,同时也是外贸出口的重要鱼类。     

月鳢的生物学特性及其养殖

月鳢的生物学特性及其养殖陈一骏，李启浩（湖北省荆州地区水产学校）月鳢（Ｃｈａｎｎａａｓｉａｔｉｃａ）属于鲈形图（Ｐｅｒｃｉｆｏｒｍｅｓ）鳢科（Ｏｐｈｉｏｃｅｐｈａｌｉｄａｅ），鳢科鱼类在我国仅乌鳢、斑鳢及月鳢３种，以月鳢体型较小，只在广酉、广东、湖南...     

投喂赤子爱胜蚓对杂交鳢生长及肌肉品质的影响

为研究赤子爱胜蚓(Eisenia foetida)作为饲料添加剂对杂交鳢(乌鳢Channa argus♂×斑鳢Channa maculata♀)生长及肉质的影响,在杂交鳢基础饲料中分别添加不同浓度(0、5 %、7.5 %、10 %)的鲜赤子爱胜蚓浆进行饲养试验,试验时间为100 d。结果表明,基础饲料中添加7.5 %蚯蚓浆能显著促进杂交鳢的生长,降低饲料系数(P<0.05),但对杂交鳢成活率没有影响;添加5 %、7.5 %的鲜蚯蚓浆,能显著提高杂交鳢肌肉中粗蛋白的含量(P<0.05),并能相应增加杂交鳢肌肉中总氨基酸(TAA)、鲜味氨基酸(天冬氨酸Asp、谷氨酸Glu、甘氨酸Gly和丙氨酸Ala)、必需氨基酸(EAA)和半必需氨基酸(HEAA)的含量;添加7.5 %、10 %的鲜蚯蚓浆,能显著提高杂交鳢肌肉中粗脂肪的含量(P<0.05)。饲料中添加不同浓度的鲜蚯蚓浆,均能显著降低杂交鳢肌肉中灰分的含量(P<0.05)。     

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.     

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.     

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.