对有分枝长石莼(缘管浒苔)的研究

报道了有分枝的和气囊状的长石莼。在山东、江苏和浙江等地分别采集到了有分枝的长石莼,对有分枝的长石莼进行研究表明,分枝有两种情况:一种是真分枝,另一种是假分枝。同时研究了有分枝的长石莼的生活史,与无分枝长石莼的生活史相同,其生活史亦是单倍的配子体与二倍的孢子体相互交替的同形世代交替。在2008年度暴发的绿潮中采到了气囊状且具分枝的类似长石莼藻体,气囊状的结构可以使此类长石莼漂浮在海面生长。漂浮的绿潮藻成为生殖细胞的附着基质,大量的生殖细胞在囊状藻体上附着生长,可能成为黄海海域漂浮海藻泛滥的原因之一。     

青岛沿海石莼属藻类暴发增殖的生物学调查与物种鉴定

2009年4月下旬～6月上旬,青岛部分内湾发生漂浮绿藻暴发性生长.本文系统调查了绿潮藻华发生的区域,以青岛湾为观测点估测了生物量,其高峰期生物量可达138 t.通过对漂浮绿藻的外观形态和显微结构观察,鉴定漂浮绿藻的样本为长石莼Ulva linza,但飘浮绿藻样本与固着生长的长石莼在形态结构上有明显的不同,主要表现为叶片宽大、细胞壁加厚.为确定其物种,作者克隆了漂浮绿藻的18S-28S rDNA转录间隔区序列(Internal Transcribed Spacer,ITS)和5S rDNA串联重复间隔区序列(5S rDNA Spacer Region,5SS),采用分子系统学方法确定漂浮绿藻样品为长石莼.本文首次报道了发生在青岛内湾的长石莼藻华,同时观察到了长石莼为适应漂浮生活在形态结构上发生的适应性变化,从而为阐释其发生机制提供依据.     

几种陆、海生植物源对仿刺参幼参生长指标的影响

使用鼠尾藻、亨氏马尾藻、石莼、浒苔、马齿苋、羊栖菜、海带等7种植物源单独投喂仿刺参幼参,一种商品饲料作为对照组,各试验设3个平行,每平行20头幼参(体质量2.5~3.5g/头),试验周期60d,之后通过对比体长、特定生长率、质量平均增加率、蛋白质表观消化率、存活率、饲养水质等指标,得出可能适宜作为幼参人工配合饵料的配料成分。试验结果表明,以体长为考核指标,各种植物源对其影响依次为:马尾藻海带200目浒苔粉鼠尾藻马齿苋石莼粉400目浒苔粉羊栖菜添加海泥400目浒苔,部分组别之间差异极显著(P0.01);以幼参特定生长率、质量平均增加率、表观消化率、饵料系数为考核指标时,鼠尾藻、马尾藻、石莼、浒苔各项数值优于其他植物源,差异显著(P0.05);马尾藻的蛋白质表观消化率高于其他植物源,羊栖菜的表观消化率值最低;浒苔、石莼、鼠尾藻、马尾藻较其他植物源更有利于幼参生长,可作为幼参人工配合饲料组分。     

饲料盐藻水平对卵形鲳鲹体色和生长的影响

以初始体质量为(13.88±0.28)g的卵形鲳鲹为试验对象,研究不同盐藻添加量(0.0%、0.1%、0.2%、0.4%、0.8%、1.6%)饲料对其体色和生长的影响。每组设3个平行,每个平行饲养20尾鱼,每日饱食投喂2次(8:00;17:00),试验周期为56d。结果显示,盐藻添加量为0.1%~1.6%时,随着饲料中盐藻水平的提高,卵形鲳鲹背部和腹部黄色值(b*)呈显著上升趋势(P0.05),饲料中添加盐藻可明显改善卵形鲳鲹体色;与此同时,卵形鲳鲹质量增加率和特定生长率随饲料盐藻水平的上升呈下降趋势(P0.05),未添加盐藻的对照组具有最高蛋白质效率和最低饲料系数,且与盐藻添加量为0.4%的试验组差异显著(P0.05),饲料中添加盐藻对卵形鲳鲹生长性能和饲料利用没有明显的促进作用;此外饲料盐藻水平对卵形鲳鲹体成分也没有显著影响(P0.05)。     

海柏和扇形海柏的形态观察及孢子萌发类型的比较

对我国大连沿海地区的海柏(Polyopes polyideoides)和扇形海柏(Polyopes affinis)进行了外部形态和孢子萌发类型的比较研究,其结果如下:(1)海柏藻体呈亚二叉分枝,上部叉分的距离较近,下部枝距较远,藻体上有轻微缢缩并偶有小育枝;扇形海柏藻体数回叉状扇形分枝,分枝处基部不缢缩或略微缢缩,下部为圆柱形,往上分枝轻度或中度扁压,藻体上多有小育枝。(2)海柏与扇形海柏孢子萌发类型均属于间接盘状型。海柏孢子萌发时,先形成基细胞,再分裂形成盘状体,不出现丝状体。扇形海柏孢子萌发时,形成基细胞后,继续分裂出现两种情况:第一种情况由基细胞逐渐延长先形成丝状体,末端细胞不断分裂,总体积膨大,丝状体逐渐变短消失,最后形成盘状体;第二种情况是在基细胞形成后,原位呈十字型分裂,形成盘状体,无丝状体形成。海柏在辽宁沿海为首次发现,是该领域的一新纪录种。     

赤潮异弯藻对孔石莼生长及其某些生理特性的影响

通过实验生态学和生物化学的方法,研究了赤潮异弯藻[Heterosigma akashiwo(Hada)Hada]对孔石莼(Ulva pertusa Kjellman)生长及其叶绿素a(Chl-a)含量、丙二醛(MDA)含量、总抗氧化能力(T-AOC)、过氧化氢酶(CAT)活力、超氧化物歧化酶(SOD)活力和谷胱甘肽过氧化酶(GPX)活力的影响。结果表明:孔石莼的克生作用会明显抑制赤潮异弯藻的生长,同时赤潮异弯藻也会抑制孔石莼的生长,且孔石莼生理生化特性对其有明显的响应。赤潮异弯藻会使孔石莼CAT活力和MDA含量呈现升高的趋势;GPX活力呈现下降的趋势;T-AOC和T-SOD活力呈现先下降后升高趋势;Chl-a含量并无明显变化。推测赤潮异弯藻克生作用诱导孔石莼产生活性氧自由基,是藻体受损伤的主要原因。     

不同光质及胁迫处理对鼠尾藻及附生藻类光合生理的影响

利用鼠尾藻(Sargassun thumbergii)、菱形藻(Nitzschia)、石莼(Ulue pertusa)和绢丝藻(Callithamnion corymbosum)作为研究对象,通过白光、蓝光、红光照射,1%硝酸铵、1%柠檬酸、3%硫酸铵处理不同时间,淡水浸泡不同时间3种杂藻清除方法,系统研究光质、药物和淡水处理对鼠尾藻及杂藻光合生理的影响。结果显示,对于相对生长速率(RGR)、表观光合速率(Pn)及表观光合速率与呼吸耗氧速率(R)的比(Pn/R),鼠尾藻幼孢子体在蓝光下均明显大于在白光和红光下,而菱形藻则在红光下较大,且鼠尾藻幼孢子体与菱形藻在蓝光下的Pn比明显大于其在白光和红光下的Pn比。结果显示,鼠尾藻幼孢子体若与菱形藻进行竞争,在蓝光下相对于在白光和红光下更有优势。硝酸铵、硫酸铵、柠檬酸药物处理对鼠尾藻幼孢子体的生理状态有一定的影响,且这种伤害具有不可逆性;对鼠尾藻嫩芽的伤害较小,且可恢复正常;对石莼的清除效果不明显,对绢丝藻有伤害。淡水处理对鼠尾藻幼孢子体有伤害,对鼠尾藻嫩芽伤害较小,对石莼影响不大,对绢丝藻有伤害。研究表明,在鼠尾藻幼苗早期培育过程中,可增大蓝光的照射或减少红光的照射,在一定程度上能促进鼠尾藻的生长且抑制菱形藻的生长;在鼠尾藻早期幼苗的杂藻清除中,应避免使用1%硝酸铵、1%柠檬酸和3%硫酸铵处理,会对鼠尾藻幼孢子体产生伤害;鼠尾藻育苗早期不宜使用淡水浸泡除去杂藻,鼠尾藻嫩芽每次淡水浸泡30 min,可清除杂藻,且对藻体无伤害。     

海参池塘青苔的危害和清除

海参池塘常见青苔的种类有:刚毛藻(钢丝藻)、水绵(棉花苔)、转板藻、浒苔、礁膜、石莼、"泥皮"等。其中刚毛藻、水绵、转板藻危害较大,且生长旺盛时不易清除。一、海参池塘青苔的危害1.导致水质清瘦透明青苔的大量繁殖会疯狂地吸收水体中的无机盐等水生     

超声波辅助酶法脱除石莼水溶性膳食纤维中蛋白质的工艺研究

本试验以蛋白质脱除率和水溶性膳食纤维(SDF)保留率作为指标,探讨各主要因素对石莼SDF脱蛋白效果的影响,并采用L_9(3~4)正交试验确定超声波辅助酶法脱蛋白的优化工艺参数。结果显示:在控制石莼SDF浓度0.6%和超声功率200 W的前提下,石莼SDF的超声波辅助酶法脱除蛋白优化工艺参数组合为:碱性蛋白酶使用量1 400 U/g、石莼SDF样液pH 11.0、超声温度50℃、超声时间1.5 h,以上述条件进行验证性试验,石莼SDF的蛋白质脱除率为(83.91±0.18)%,SDF保留率为(86.23±0.25)%,蛋白质脱除效果优于正交试验9个处理组。     

中国沿海石莼属绿藻的ITS和5S rRNA序列分析

对采自2008年、2009年中国沿海的石莼属(Ulva)海藻进行了ITS基因间隔区序列和5S rRNA序列系统发育分析,探讨了绿潮藻的分类问题。根据ITS序列分析结果,绿潮藻中存在着几个不同的种,包括LPP复合体(Ulva linza-procera-prolifera)中的种类以及Ulva compressa。绿藻的5S rRNA序列系统分析结果的差异性较明显,但也在一定程度上印证了上述结论。根据本文中ITS基因间隔区及5S rRNA序列分析结果,本实验采集到的绿潮藻的后代中至少存在U.prolifera、U.linza和U.compressa三个种类。据此推断,我国黄海海域2008年、2009年爆发的绿潮中,存在上述三个种类。     

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).