大黄鱼种质资源研究进展

大黄鱼(Pseudosciaena croceaRichardson),属石首鱼科、黄鱼属,俗称黄鱼、黄花鱼等,为暖水性集群洄游鱼类,生活于近海的中、下层[1]。主要分布于我国黄海南部、东海和南海,分为3个地理种群:岱衢族、闽—粤东族和硇洲族。大黄鱼曾是我国著名的四大海洋捕捞对象之一,也是浙江省的重要经济鱼类,国内外都有许多大黄鱼的相关研究报道[2-4]。20世纪70年代前东海区最高年产量达2.0×105t。但是,由于过度捕捞,大黄鱼资源遭到毁灭性的破坏,产量急剧下降。到80年代末90年代初,年产量仅为2000 t,而且多为幼体,成鱼数量很少;在大黄鱼的网箱养殖中,出现…     

养殖大黄鱼不同部位营养成分研究

大黄鱼（Pseudosciaena crocea Richardson）属鲈形目,石首鱼科,黄鱼属,俗名黄花鱼、黄瓜鱼,是我国传统的海产经济鱼类。由于过度捕捞,导致资源严重枯竭。大黄鱼已在全国范围广泛养殖。产区主要集中在浙江沿海和福建闽东地区,到2007年大黄鱼养殖产量达到了10万吨。大黄鱼个体较大,     

中国大黄鱼养殖产业成本与贸易效益分析(下)

三、中国大黄鱼养殖产业的生产成本分析 1．大黄鱼养殖或者加工的成本模型 （1）大黄鱼养殖成本模型①-成本价格20元／千克。2007年浙江大黄鱼养殖每尾成本估算见表3。     

不同家系大黄鱼肌肉营养成分的比较

对同等养殖条件下所养成的大黄鱼[Pseudosciaena crocea(Richardson)]3个不同家系:WW家系[野生F1(♀)×野生F1(♂)]、WC家系[野生F1(♀)×养殖F8(♂)]和CC家系[养殖F8(♀)×养殖F8(♂)]成鱼肌肉营养成分进行测定,并以野生大黄鱼作为对照,从营养成分的角度分析和评价不同家系大黄鱼的品质。结果显示,野生大黄鱼粗蛋白含量、必需氨基酸以及鲜味氨基酸总量都明显高于家系大黄鱼,而必需脂肪酸含量则低于家系大黄鱼。3个家系之间,粗蛋白质含量、必需氨基酸总量、鲜味氨基酸总量及必需氨基酸指数排列次序由大到小依次为:WW、WC、CC;饱和脂肪酸总量由大到小的排序为:CC、WW、WC;不饱和脂肪酸总量由大到小依次为:WC、WW、CC。研究认为,家系之间主要营养成分指标存在一定差异,这是由遗传因素决定的,因此通过家系选择进行大黄鱼肉质改良是可能的,但是同时必须结合饲料营养成分的补充和调控以及养殖环境条件的改善,才能较快速地使养殖大黄鱼的品质达到或接近野生大黄鱼的水平。     

天津地区大黄鱼苗种工厂化培育试验

正大黄鱼又名黄花鱼,是我国近海的重要名贵鱼类之一[1]。大黄鱼体黄唇红,肉质鲜美,素有"国鱼"之美誉,备受消费者的青睐[2]。大黄鱼为暖温性近海集群洄游鱼类,分布于北起黄海南部,经东海、台湾海峡,南至南海雷洲半岛以东地区,栖息于水深60 m以内的沿岸和近海水域的中下层,以鱼虾等为食[3]。我国大黄鱼养殖是从福建开始,向浙江、广东,海南等省辐射,养殖方式有网箱养殖、围网养殖和池塘养殖等多种模式,均取得良好效果和较好的经济效益。天津地区海水工     

大黄鱼越冬试验

大黄鱼是多年生高价值的经济鱼类,其养殖周期至少要18个月,故大黄鱼人工养殖必须经过一个漫长的冬季。尽管福建以南的海域大黄鱼养殖能安全越冬,但由于大黄鱼属深层鱼类,所以在我国浙江以北的大部分海域大黄鱼人工养殖越冬还是成为广大养殖业者所担心的主要问题和所要解决的主要技术问题之一。为此,1997年我们进行了大黄鱼的越冬试验,试验的主要目的是要搞清楚大黄鱼的停食温度,极限致死温度和进食温度等。一、材料与方法1、鱼种来源大黄鱼鱼种来源于我公司放养的规格为2．scm／尾的鱼苗,经过6个多月的养殖,体长达到16一18cm／尾,…     

养殖大黄鱼的病害及防治

大黄鱼[Pseudosciaenacrocea(Richardson)]曾是我国最主要的经济鱼类。80年代后由于资源衰退,产量大减。通过多年的研究,大黄鱼人工繁殖已获成功。近年来浙江的宁波、舟山、温州、台州等沿海地区都已进行人工养殖。但随着养殖规模的扩大,生产水平和集约化程度的不断提高,养殖大黄鱼的病害已经发生,且日趋严重。从近期对我省各地养殖大黄鱼病害发生情况的调查及取样分析结果来看,不同规格的大黄鱼其病因、病原、疾病种类亦不相同,现将目前我们了解的危害较大的大黄鱼养殖期间病害及防治方法简述如下：一、苗种期间的病害及防治：1．…     

大黄鱼人工育苗技术

大黄鱼属于石首鱼科黄鱼属,俗称黄花鱼,为我国特有的地方性养殖品种,是传统四大经济鱼类之一.目前,大黄鱼人工育苗主要集中在闽东地区,对于大黄鱼仔、稚、幼鱼培育技术尚未见报道.本文对大黄鱼育苗技术进行了生产性总结,旨在为石首鱼科鱼类的人工育苗提供参考.     

不同养殖模式对大黄鱼肉质的影响

对工厂化养殖模式、网箱养殖模式养殖的大黄鱼和野生大黄鱼进行了肌肉常规营养成分、氨基酸和脂肪酸的分析比较。研究结果表明,工厂化养殖模式和网箱养殖模式的大黄鱼粗蛋白含量均显著低于野生大黄鱼(P0.05),粗脂肪含量均显著高于野生大黄鱼(P0.05)。工厂化养殖模式的大黄鱼必需氨基酸总量、呈味氨基酸总量和氨基酸总量均显著高于网箱养殖大黄鱼,但显著低于野生大黄鱼(P0.05)。工厂化养殖模式的大黄鱼多不饱和脂肪酸以及二十碳五烯酸+二十二碳六烯酸均显著高于网箱养殖的而显著低于野生大黄鱼(P0.05)。工厂化养殖模式养殖大黄鱼可以生产出肉质营养结构和风味优于传统网箱养殖的大黄鱼。     

大黄鱼低盐养殖生长性状的相关性和遗传力分析

通过对选育大黄鱼进行低盐养殖,采用通径系数分析了12月龄低盐养殖大黄鱼体高、体长和体质量的相关性并估算遗传力。试验结果表明,低盐养殖大黄鱼体长与体质量的相关关系(0.957)最大,体长对体质量的直接作用(0.658)最高;建立大黄鱼低盐养殖模式多元回归方程为m=-143.694+13.062L(r2=0.959),经显著性检验,体长对体质量的偏回归系数及回归常数均达到了极其显著水平(P0.01);分析低盐养殖大黄鱼体高、体长和体质量的现实遗传力分别为0.623、0.681和0.363均明显高于自然海水养殖大黄鱼的体高(0.178)、体长(0.548)和体质量(0.110)。低盐环境养殖的大黄鱼选育子代可以更好的继承亲本性状,应进行大黄鱼抗低盐育种。     

Association between the interannual variation in the oceanic environment and catch rates of bigeye tuna (Thunnus obesus) in the Atlantic Ocean

The environmental processes associated with variability in the catch rates of bigeye tuna in the Atlantic Ocean are largely unexplored. This study used generalized additive models (GAMs) fitted to Taiwanese longline fishery data from 1990 to 2009 and investigated the association between environmental variables and catch rates to identify the processes influencing bigeye tuna distribution in the Atlantic Ocean. The present findings reveal that the year (temporal factor), latitude and longitude (spatial factors), and major regular longline target species of albacore catches are significant for the standardization of bigeye tuna catch rates in the Atlantic Ocean. The standardized catch rates and distribution of bigeye tuna were found to be related to environmental and climatic variation. The model selection processes showed that the selected GAMs explained 70% of the cumulative deviance in the entire Atlantic Ocean. Regarding environmental factors, the depth of the 20 degree isotherm (D20) substantially contributed to the explained deviance; other important factors were sea surface temperature (SST) and sea surface height deviation (SSHD). The potential fishing grounds were observed with SSTs of 22–28°C, a D20 shallower than 150 m and negative SSHDs in the Atlantic Ocean. The higher predicted catch rates were increased in the positive northern tropical Atlantic and negative North Atlantic Oscillation events with a higher SST and shallow D20, suggesting that climatic oscillations affect the population abundance and distribution of bigeye tuna.     

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.     

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.     

Growth performance,digestive enzyme activity and immune response of Japanese sea bass,Lateolabrax japonicus fed with fructooligosaccharide

In this experiment, a feeding trial was performed to determine the effects of fructooligosaccharide (FOS) on growth performance, digestive enzyme activity and immune response of Japanese sea bass, Lateolabrax japonicus juveniles (initial weight 38.3 ± 0.5 g), and the fish were examined following feeding with six levels of FOS (0, 0.5, 1, 2, 4 and 6 g/kg) for 28 days. Significant enhancement of weight gain (WG) and specific growth rate (SGR) was found in fish fed 1 g/kg FOS incorporated diets (p < .05), while the feed conversion ratio (FCR) in the 1, 2 g/kg FOS groups reduced significantly compared with the control (p < .05). Besides, the crude lipid in the 4, 6 g/kg FOS groups increased significantly compared with the control (p < .05). On the other hand, the erepsin and lipase activities significantly elevated in intestine of fish fed 2 g/kg FOS (p < .05) and the lysozyme activity in serum of fish fed 2 g/kg FOS were significantly higher than that in the control (p < .05). Moreover, the alkaline phosphatase activities in serum of fish fed 0.5, 1, 2 g/kg FOS were significantly higher than in control (p < .05). Regression analysis showed that the relationships between dietary FOS levels and either SGR, FCR, erepsin or lysozyme activities were best expressed by regression equations, and the optimal inclusion levels are 1.37, 1.80, 3.06, 3.11, 1.93 and 1.80 g/kg for SGR, FCR, erepsin, lipase, lysozyme and total superoxide dismutase activities, respectively. Overall, this study revealed that FOS incorporated diets could beneficial for L. japonicus culture in terms of increasing the growth, digestion and immune activities. Under the present experimental condition, the optimal supplementary level of FOS in the diet of L. japonicus is 1–3 g/kg.     

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).