应用地热水高密度饲养稚甲的越冬试验

人工养殖甲鱼的中心问题是缩短养殖周期，达到高产，高效的目的。在常温饲养条件下，每年夏秋季孵化脱壳的稚甲鱼，其个体重量仅为4-5克，且不久即进入半年以上的冬眠，越冬期间死亡率很高，据资料介绍：在自然条件下饲养的稚甲鱼，越冬成活率大约为20-30％；而且体重下降5-10％；要经过二年饲养才能达到50克左右。     

甲鱼快速生长及效益的研究

在自然条件下,稚甲鱼的生长要达到500克的商品规格,通常要经过4—5年的饲养期。人工养殖甲鱼如何加快生长速度,缩短养殖周期,达到高产、高效的目的。本文就1988年进行的稚甲鱼在地热水条件下,饲养一周年的生长速度及经济效益研究报告如下: 材料和方法     

室内外结合养甲鱼

辽宁省辽东甲鱼养殖技术培训中心甲鱼养殖试验场近两年来探索出一套北方地区甲鱼快速育肥技术,将7、8月份产卵孵化出的3—5克稚甲鱼移入人工控温工厂化养殖厂房稚申鱼培育地进行越冬培育,体重达到100克左右,在第二年5月份移到室外土池或鱼池进行人工饲养,经过18个月的时间(其中有7个月是越冬休眠不活动期)雄甲鱼平均体重达到750克,雌甲鱼平均体重达到550克。     

加速稚鳖生长促进性成熟的技术

为了摸索如何在自然条件下加速甲鱼生长促进其性成熟，我们在60平方米水泥地中饲养刚孵出的体重3～5克／只的稚鳖，采用改良生态条件、合理投喂和水流刺激等方法．使稚鳖经一年饲养平均体重达到191克／只．成活率97％；其中4.1％体重达到0．5公斤以上，并已性成熟，主要做法如下。1改良生态条件水泥池经生石灰消毒后铺垫软泥沙，厚约30厘米，池中间栽种茨茹等水生植物，60％～80％水面市水葫芦等水草。水生植物吸收了水中养份，大大降低了残饵、甲鱼排泄物造成的污染。水生植物的代谢也增加了水中溶氧．促进了甲鱼的援食生长。甲鱼对水体的…     

乌龟稚龟的生长研究

应用恒温恒湿人工气候箱,加温养殖和室内常温养殖,对乌龟稚龟在越冬期间的生长情况进行了研究。结果显示,在常温养殖下,龟在越冬期间生长速度呈下降趋势,于翌年开春后温度回升时,生长速度开始加快。恒温(30℃)养殖下,生长速度基本上呈直线上升(背甲长、背甲宽和体厚)或指数函数曲线上升(体重)。恒温下饲养与常温下饲养的结果相比较,其体重、背甲长、背甲宽、体厚的测量值均有明显的差别(均为P<0 0001),乌龟在恒温下饲养的生长速度明显快于常温下饲养的生长速度。常温下体重的生长模式为:W=6.8642-0.0206D+0.0001D2。恒温下体重的生长模式为:W=6.570466e0.007732D。实验表明:温度与乌龟的生长有密切关系,加温可以促进乌龟稚龟的生长。     

第三讲 甲鱼的越冬育种及其商品养殖

第三讲甲鱼的越冬育种及其商品养殖王宾贤（湖南省水产研究所４１３１００）甲鱼在其生命过程中，不同的发育阶段有不同的生长特点。一般对甲鱼的不同生长阶段作如下划分：自孵化脱壳之日起，至体重为５０克阶段称为稚鳖阶段；个体重５０克至个体重２５０克阶段称为幼鳖阶...     

甲鱼饲料中无机盐添加剂的研究

23．15—4．05g／只重的稚甲鱼为试验材料，在水温为19-27℃的条件下，经30天饲养对比试验。结果表明：添加试验Ⅰ、Ⅱ组无机盐的稚甲鱼月增重率为126．35％，118．00％，分剐为对照组97．91％的129．05％，120．52％，饲料系数为2．86，2．93，分别比对照组的3．41低0．55，0．48。     

地热水养殖甲鱼技术研究的综合报告（摘要）

一、研究课题的提出：在自然饲养条件下，把甲鱼养成700-800克的规格，需要4～5年的时间，自1970年以来，日本利用加温养殖，打破甲鱼的冬眠期，在12-15个月内把甲鱼养成商品规格，大大促进了日本甲鱼养殖业的发展，1988年年产量为495吨，目前，日本养殖甲鱼的技术水平、每平方米面积的甲鱼产量一般为1．6-2．0公斤，投产比为1：1．37，甲鱼的人工养殖，在我国大陆各省起步较晚，     

控制稚鳖整齐出壳技术

稚鳖的孵化是甲鱼人工养殖生产中最重要的一个坏节。在生产中，无论是自然孵化，还是人工孵化，由于多种因素，稚鳖的出壳时闻常会先后不一，给稚鳖的饲养与管理带来不少麻烦。这里向读者介绍—项控制稚甲鱼整齐出壳的技术——浸水刺激稚甲出壳法。     

两段式人工加温养殖甲鱼模式

我们于1996年7月开始进行两段式养鳖试验,该试验目前已基本结束,现把试验情况分析如下：1．模式原理该模式的设计原理是：根据甲鱼的生理生长需要,在确保12～14个月养殖期的前提下采取适度的人工加温手段,使甲鱼摄食生长始终处于最佳状态,降低温室造价、燃料费用,提高成活率,从而达到降本增收目的。2．操作步骤门）稚甲鱼养殖阶段（7～11月）：9月底以前通过采取保温措施,水温控制在30～3iC的最佳温度。10～11月外界温度不断下降,此时采用人工补充热量的办法,适当加温便可使水温达到30C,本阶段结束稚甲平均体重可达70克。（2）…     

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.     

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.     

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.     

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.