水环境中Ca^2＋,Mg^2＋对中国对虾生存及生长的影响

通过单因子静态急性毒性试验和正交设计法,研究水环境中Ｃａ＾２＋、Ｍｇ＾２＋、Ｃａ＾２＋、Ｍｇ＾２＋总量及Ｃａ＾２＋／Ｍｇ＾２＋比值对中国对虾生存及生长的影响。结果表明：（１）中国对虾在水环境中能够生存的Ｃａ＾２＋、Ｍｇ＾２＋质量浓度范围分别为２４．９２￣２８０．６６ｍｇ／Ｌ、３４．５￣３４４．９ｍｇ／Ｌ;（２）Ｃａ＾２＋／Ｍｇ＾２＋比值为１：１０,对中国对虾的生存没有影响;（３）中国对虾的生长与Ｃ     

几种重金属离子毒性对黑鲷孵子和稚鱼的影响

在黑鲷人工繁殖中，发现海水中重金属离子对黑鲷的稚鱼及孵子的发育有影响，因而作了Ｈｇ＾２＋，Ｃｒ＾６＋，Ｆｅ＾２＋，Ｃｕ＾２＋几种重金属离子对黑鲷雅鱼影响的探讨。找出安全浓度，并提出亚铁的毒性不可忽略，其特点为死亡界限明显，过渡段；时发现几种毒物随着水温的升高。其毒性由强到弱的排列顺序为：Ｈｇ＾２＋＞Ｆｅ＾２＋＞Ｃｕ＾２＋＞Ｃｒ＾６＋，用直线内插法求出了ＴＬｍ２４、ＴＬｍ１８、ＴＬｍ９６浓度。     

中华绒螯蟹育苗用水中Mg_2_与_省略_g_2_Ca_2_对出苗率的影响

报道了中山绒螯蟹育苗用水调配原则与不同基础水调配方法的研究结果,育苗用水调配的的基本原则是Ｍｇ＾２＋与Ｃａ＾２＋含量及Ｍｇ＾２＋／Ｃａ＾２＋比值（Ｒ）必须达到一定的范围,以渔塘水与深井水作基础水时,需分别添加６种与１０种化学药品,其中Ｍｇ＾２＋与Ｃａ＾２＋含量及Ｒ值可适范围均分别为４８４～８１６ｍｇ／Ｌ与１７８～３４０ｍｇ／Ｌ,Ｒ值均为２．０～３．０研究表明,以可口水育苗最为经济,如盐度或Ｍｇ＾２     

枝角类适种探索和休眠卵的利用

实验表明多刺裸腹蚤是最易培养的淡水枝角类。适宜条件下接种后６ｄ可达５０００个／Ｌ的生一,人为改变饵 料及水温条件可获得大量休眠卵。休眠卵无休眠期,适宜条件下可卵化。孵化时数与水温的为Ｈ＝４７４．３２５９－２９．４５１５Ｔ＋０．４７８３Ｔ＾２。干燥低温保存休眠卵效果较好。１年后的孵化率可达６０％。     

汞对草鱼卵子孵化的影响

本文研究Ｈｇ＾２＋对草鱼受精卵孵化的影响,结果表明：当Ｈｇ＾２＋的浓度大于０．０４ｍｇ／Ｌ时孵化率显革降低,当Ｈｇ＾２＋的浓度大于０．１６ｍｇ／Ｌ时则孵化率为０。     

河蟹人工海水育苗水质的监测与调控

根据水质监测结果,河蟹人工海不育苗的技术关键是：将各元素按比例合理配制人工海水,ａ＾２＋：Ｍｇ＾２＋＝１：２￣３之间,并充分搅拌、曝气、保持夫工涨水中Ｃａ＾２＋、Ｍｇ＾２＋、ＳＯ４＾２－、ｐＨ、Ｓ的稳定性;采取增与锅炉加温等措施,及时调节Ｄｏ、温度;在蚤幼Ｚ４￣Ｚ５期加大力度换水,及时清淤２,循环水经处理曝气后重新利用,有效控制水体中ＮＨ４＝Ｎ、ＮＯ２－Ｎ含量．通过定时、定量投入抗 经可达到杀灭人     

甲基汞对鲤鱼血浆渗透压及鳃丝Na^＋—K^＋—ATPase活性的影响

以水体甲基汞不同浓度（μｇ／Ｌ）分别染毒鲤鱼２４小时和１周。实验结果表明：在浓度高于５０μｇ／Ｌ染毒２４小时和浓度２０μｇ／Ｌ染毒１周时，多数染毒鱼的血浆Ｋ＾＋和Ｍｇ＾２＋浓度增高，Ｎａ＾＋和Ｃｌ＾－浓度下降，ＰＯ４＾３－值变化不明显。血浆Ｃａ＾２＋浓度仅在２００μｇ／Ｌ染毒２４小时和高于４０μｇ／Ｌ染毒１周时，染毒鱼的血浆Ｃａ＾２＋出现极显著下降。甲基汞量高于１００μｇ／Ｌ染毒２４小时和８０μｇ     

Cu^2＋Zn^2＋和Cd^2＋对5种单细胞藻类生长的影响

报道承Ｃｕ＾２＋Ｚｎ＾２＋和Ｃｄ＾２＋的毒性作用下,三角褐指藻、湛江叉鞭藻、路氏巴夫藻、青岛大扁藻和小球藻等单细胞藻类的生长速度,密度都发生了不同程度的变化,叉鞭、扁藻及巴夫藻易中毒且恢复慢,当金属离子浓度较低时生长仍然缓慢。而小球藻和三角褐指藻耐毒能力较强,在２００×１０＾－６,甚至６００×１０＾－６离子浓度下仍可生长 。     

团头鲂配合饲料中锰和钴添加量的研究

试验按两因子三水平有重复试验设计，网箱养团头鲂。经９０天饲养结果表明，配合饲料中锰（Ｍｎ＾２＋）和钴（Ｃｏ＾２＋）的添加量分别为１２．９ｐｐｍ和２３．４ｐｐｍ时，团头鲂鱼种的生长效果相对最佳，饲料中添加适量的Ｃｏ＾２＋对团头鲂的生长有促进作用，且在０－２３．４ｐｐｍ范围内有递增趋势，当Ｍｎ＾２＋的添加量为２５．８ｐｐｍ时，其生长相对减慢。     

Hg^2＋抑制石斑鱼呼吸运动的研究

本文用微机记录，分析，实验数据用勒让特正交多项式拟合处理，研究致死浓度Ｈｇ＾２＋溶液对石斑鱼呼吸运动的抑制作用，初步探讨了Ｈｇ＾２＋中毒致死的可能机理。     

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.     

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).     

The optimal dietary protein level of juvenile silver sillago Sillago sihama at three dietary lipid levels

A 5 × 3 factorial growth trial was conducted to evaluate optimal dietary protein and lipid levels (dietary protein level, DP; dietary lipid level, DL) for juvenile Sillago sihama (S. sihama) (2.0 ± 0.02 g, initial weight). Fish were fed 15 diets containing 5 DPs (350, 400, 450, 500 and 550 g/kg) and 3 DLs (60, 90 and 120 g/kg) for 8 weeks. The interaction between proteins and lipids significantly influenced the feed conversion ratio, condition factor, body composition, antioxidant indices and lipase activity (p < .05). DP 450 g/kg showed the highest average final body weight. DPs 500 and 550 g/kg significantly decreased the protein efficiency ratio (p < .05). DL 120 g/kg showed the highest percentage weight gain. The low feed conversion ratio was found in diets P45L12, P55L9 and P55L12. Diet P45L12 showed high superoxide dismutase activities. DP 450 g/kg showed the lowest average malondialdehyde content. Lipase activity was increased by increasing DP (p < .05) with a fall at DP 550 g/kg. Under the present experimental conditions, the optimal DP for S. sihama was 450 g/kg under the DL 120 g/kg.     

Vitamin D3 and the renal handling of phosphate in American eels

Cholecalciferol (Vitamin D₃) increased plasma inorganic phosphate concentration in American eels,Anguilla rostrata, in a dose-dependent fashion. This response was more marked in phosphate loaded fish. In control as well as phosphate loaded eels the hyperphosphatemic response to D₃ was associated with a sharp reduction in renal phosphate clearance relative to¹⁴C-polyethelene glycol (PEG) clearance. Glomerular filtration and urine flow rates were not affected by D₃. As renal phosphate clearance, even in phosphate loaded eels, never significantly exceeded that of PEG, it is suggested that D₃ reduced the relative clearance rate of phosphate by increasing renal phosphate reabsorption rather than by reducing the tubular secretion of phosphate.