Experimental studies on intensive polyculture of Chinese shrimp with bay scallop

用放在海水池塘中的８个陆基围隔（５０ｍ×５０ｍ×１８ｍ），研究中国对虾（Ｐｅｎａｅｕｓｃｈｉｎｅｎｓｉｓ）与不同密度海湾扇贝（Ａｒｇｏｐｅｃｔｅｎｉｒａｄｉａｎｓ）投饵混养的放养方式、生产力和极限放养量。对虾体长（２８５±０１６）ｃｍ，扇贝壳长（１１０±０１２）ｃｍ，放养密度分别为６０尾／ｍ２和０，１５，４５，７５粒／ｍ２，用投饵和施肥（鸡粪和化肥）饲养。结果表明，扇贝密度为０和１５粒／ｍ２时，对虾的成活率无显著差异。混养（扇贝１５粒／ｍ２）时对虾的出塘体长、体重和产量分别比单养高２５％，３８％和６５％；当扇贝密度高于１５粒／ｍ２时，对虾的平均体长、体重和产量随扇贝密度的增加而显著减少（Ｐ＜００５）。扇贝密度为１５和７５粒／ｍ２时，其产量由４７０ｋｇ／ｈｍ２增至１２３６ｋｇ／ｈｍ２；当扇贝密度高时，去壳后湿重占体重的百分数从（４２８４±３４４）％降至（３７８８±４２６）％。扇贝的极限放养量为６００～８００ｋｇ／ｈｍ２，适宜放养密度为１０～１５粒／ｍ２。     

对虾源副溶血弧菌拮抗菌的筛选与评价

随着对虾养殖产业集约化程度不断提高,对虾病害的发生越来越多,成为制约产业发展的主要因素。自江苏南部沿海滩涂沉积物中分离得到252株细菌,以14株凡纳滨对虾急性肝胰腺坏死综合征致病性副溶血弧菌为指示菌,经过初筛和复筛,得到1株拮抗效果较好的菌株H0011;经形态、生理生化特性和16S rDNA基因序列鉴定,确定菌株H0011为普罗威登斯菌。利用普罗威登斯菌H0011对凡纳滨对虾进行高密度胁迫试验测试其安全性,试验期间浸浴组和投喂组对虾状态良好,无发病和死亡现象。对普罗威登斯菌H0011的生长条件优化后,最优生长温度为30℃,盐度为10,pH为8。普罗威登斯菌H0011 4 h进入对数生长期,20 h达到生长高峰。本研究获得了对凡纳滨对虾急性肝胰腺坏死综合征具有防控作用的高效拮抗作用菌,将为对虾急性肝胰腺坏死综合征的防控提供新的思路。     

中国对虾败血病病原菌（气单胞菌）的致病性与生物学性状

本文从患败血病的中国对虾的血淋巴中分离到嗜水气单胞菌和豚鼠气单胞菌，经人工感染试验证实为此败血病的病原菌。两种病原菌均为革兰氏阴性，极生单鞭毛能运动的短杆菌，在ＴＣＢＳ上不生长，对０／１２９不敏感，在不含ＮａＣｌ的基础培养基能生长。氧化酶，过氧化氢酶阳性，利用蔗糖，麦芽糖和淀粉产酸不产气，利用果糖，甘露醇，半乳糖和密二糖产酸产气，不发酵乳糖，肌醇，山梨醇，木糖，蕈糖等，精氨酸水解，色氨酸脱氨阳性。     

饵料蛋白量对于日本对虾幼虾生长,消化效率和氮排泄的影响

研究了饵料蛋白量对日本对虾（Ｐ．ｊａｐｏｎｉｃｕｓ）幼虾生长、消化率、氨和尿素排泄的影响。按照同等热量主要以蟹蛋白配制了５种蛋白（２１％～６１％）干饵料，并且在３０ｄ中每天按体重的６％比例来投喂对虾（平均初湿重为０．４ｇ）。在试验结束时，以蜕皮中期的对虾（湿重０．５～２．０ｇ）用作计算干物质和蛋白质的消化率和氨与尿素的排泄率。投喂含２１％和３１．４％蛋白饵料的对虾的增重、特定生长率（ＳＧＲ）和饵料     

Enhancement of Chinese shrimp in northern Yellow Sea, China

根据１９８５～１９９２年黄海北部中国对虾幼虾放流前后相对资源量资料,估算放流虾在混合虾群中占的平均比例约为９２％,平均回捕率９２％。放流量（Ｘ）与放流后相对资源量（Ｙ）的关系为Ｙ＝２４１０Ｘ－１００３Ｘ２,Ｒ＝０８９８。经Ｆ—检验相关显著。结果表明：中等放流量才能获最好增殖效果;与最大渔获量相应的放流量约１６亿尾;与最大相对资源量相应的放流量约１２亿尾。描述了放流虾的死亡特征,并估算了各类死亡值。用Ｃｏｈｏｒｔ分析方法估算了放流虾到开捕时（８月１５日）的存活数量,平均占放流量的１０５％。渔汛的捕捞死亡率约０８２,自然死亡率０１１,其余００７游出黄海北部去越冬场     

投饲次数对网箱中鲤生长的影响

网箱饲养试验表明，在１７０—２００℃时每周投喂６、５和４天时，鲤（重１９３５—２７８０ｇ）的体重瞬时增长率（ＳＧＲ，％／日）分别降低３３１％、３９４％和５００％。５、６、７、８月网箱养鲤（５８８±２８９ｇ）的适宜日投饲次数分别为３、４、５—７和６—５。     

刀额新对虾的快速自溶技术

通过对刀额新对虾快速自溶影响因素的研究,为虾组织快速自溶技术提供了一个基本模式。结果表明：紫外线照射２０分种、Ｎａ＾＋对虾组织快速自溶有促进效果,而Ｋ＾＋、Ｃａ＾２对虾组织自溶基本无影响;ｐＨ７．０～７．５时,自溶效果最佳;采用４５～６０℃（５℃／ｍｉｎ）的梯度温度优于４５℃、５５℃、６５℃恒温反应的效果。虾组织自溶反应时间为３小时左右,蛋白质水解率可达８０％以上。     

皱纹盘鲍幼鲍溃烂病病原菌的研究

从患有溃烂病的皱纹盘鲍幼鲍体上，分离到一种致病性细菌。经人工感染试验，证实该菌为皱纹盘鲍幼鲍溃烂病的病原菌。显微镜观察该细菌为革兰氏阴性，极生１～３根鞭毛，能运动的杆菌，大小为０．７～０．８×２．３～２．８ｕｍ。经细菌分类试验鉴定，该菌生长最适温度为２０～３０℃，最适ｐＨ值５．５～８．５。该菌在培养基Ｂ上产生蓝色的荧光素。能利用葡萄糖产酸不产气，果糖、Ｄ－半乳糖、甘露糖、木糖、阿拉伯糖、海藻糖发酵反应阳性，不能发酵乳糖、麦芽糖、鼠李糖、蔗糖，可分解山梨醇、肌醇、肌苷。过氧化氢酶、脲酶、氧化酶、及明胶液化反应阳性；能利用柠檬酸，不还原亚硝酸盐，不产生吲哚和硫化氢，ＭＲ和Ｖ．Ｐ．试验阴性。初步鉴定该病原菌为荧光假单胞杆菌。还进行了病原菌药敏试验，该菌对卡那霉素、呋喃唑酮、恶喹酸敏感，这些药物可作为防治该病的首选药。     

饲料中必需脂肪酸对中国对虾体内必需脂肪酸含量的影响

用正交设计法设计亚油酸（１８∶２ｎ－６）、亚麻酸（１８∶３ｎ－３）、二十碳五烯酸（２０∶５ｎ－３）和二十二碳六烯酸（２２∶６ｎ－３）３因素、３水平饲喂中国对虾试验,结果表明,对虾体内４种必需脂肪酸（ＥＦＡ）含量随饲料中４种必需脂肪酸含量增加而增加。当饲料中亚麻酸、二十碳五烯酸和二十二碳六烯酸含量分别为０．８４％～１．１０％、０．２１％～０．４８％和０．３７％～０７４％时,养殖对虾与野生虾体内这３种必需脂肪酸含量接近。由于饲料中亚油酸含量较高,所以养殖虾体内亚油酸含量高于野生虾。     

牛蛙爱德华氏菌病的研究

１９９３年９月－１９９４年５月，作者对牛蛙的肝、眼内水样液进行了病原菌分离、人工感染、病原菌生理、生化特性和药物的敏感性的测定，观察了病理组织变化等。结论认为病原菌为革兰氏阴性、周身鞭毛能运动的短杆菌；氧化酶、Ｖ－Ｐ反应阴性，过氧化氢酶、Ｈ２Ｓ产生、吲哚反应、甲基红反应为阳性；最适生长所需温度、盐度和ｐＨ值分别为３０－３５℃、５－１０‰和７．０。病菌为迟钝爱德华氏菌，它对吡哌酸、复方新诺明、氯霉素     

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.