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1.
本首次报道了陆封型大西洋鲑发眼卵孵化技术,孵化水温3-11℃,积温达到140-221度日破膜孵出稚鱼,孵化率北京房山87.6%,黑龙江渤海81.9%,经21-28d胚后发育上浮平游开食。同时介绍了苗种培育技术和管理方法。  相似文献   

2.
泥鳅全人工繁殖技术及胚胎发育研究   总被引:6,自引:0,他引:6  
本文报道了用人工繁殖获得的泥鳅苗培育成亲鱼和人工催产、孵化技术以及胚胎发育全过程的形态特征。催产亲鱼为二冬龄,健产药物HCO,剂量20-35IU/g,健产率95%,孵化率78.80-85.6%.43天后,幼鱼外部形态发育完全.  相似文献   

3.
乌鳢人工繁殖及苗种培育试验   总被引:1,自引:0,他引:1  
进行了乌鳢人工繁殖及苗种培育试验,采取强化培育亲鱼,塑料大棚水泥池催产孵化,水泥池和土池培育鱼种以及泼洒药液等技术措施,结果;50组亲鱼共产卵150万粒,平均受经率74.58%。孵出鱼苗113万尾,平均成活率47.32%,育成鱼种51.2万尾。试验证明:催产孵化以6月中旬至7月上旬为宜,孵化最适水温为23-26℃。认鉴定认为,试验结果达省内先进水平。  相似文献   

4.
山女鳟人工受精孵化技术初步研究   总被引:4,自引:2,他引:2  
从日本引进的山女鳟发眼卵育成亲鱼后,以挤腹法采孵,取精,干导法人工受精,经30-60分钟止水膨胀后入桶式孵化器进行流水孵化,发展率25.2%,孵化稚鱼畸形率5.1%,患脐囊白点症的占7.3%,稚鱼体质软弱,受精后1-分钟内采用免膨法将卵将卵直接入桶孵化,发眼率59.4%,孵化稚鱼98%以上发育正常,畸形率3.6%,水质澄清孵化水温12℃试验组发眼率95.1%,孵化率94.0%,孵化稚鱼体质良好。  相似文献   

5.
研究了稀土Ce^3 对草鱼受精卵孵化和鱼种生长的影响,Ce^3 的最佳浓度范围为2.4-4.8mg/L,可提高孵化率20.2%-21.7%,铈对孵化的促进作用是通过受精卵对铈的吸收实现的,饲料中添加3.2-12.8mg/kg的铈可提高草鱼鱼种生长率9.56%-13.86%。  相似文献   

6.
乌鳢人工繁殖试验初探   总被引:2,自引:0,他引:2  
1996年5月28日,选择17组乌鳢亲鱼,在孵化槽、产卵池进行人工催产孵化。用轮叶黑藻、水荷叶作鱼巢,一次注射DOM加LRH-A,催产率、受精率、孵化率分别为100%、82.9%、71.7%。共出苗20.8万尾。  相似文献   

7.
人工饲养2-3年的暗纹东方Tun,平均体重为750g,催产3尾雌体和4尾雄体,经人工授精获受精卵30余万粒,催产率100%,受精率98.5%,其中静水孵化(干法受精不脱粘)10万粒,孵化率98.5%,流水孵化(半干法受精不脱粘)受精卵20万粒,孵化率65%,共孵化出幼苗23万尾。研究了在暗纹东方Tun人工孵化中,脱粘与不脱粘的条件。  相似文献   

8.
专塘培育鳜鱼亲鱼,用HCG+LRH-A作为催产剂,胸腔2次注射,分4批催产,受精率90 ̄98%,将受精卵放入孵化环道流水孵化,孵化率34.0 ̄38.3%,以刚脱膜的团头鲂作为开口饵料,进行鱼苗环道培育,共育出2.5 ̄3.0cm夏花鳜种12.5万尾,成活率30 ̄40%。  相似文献   

9.
本研究阐述了运用工业化养鱼技术生产三倍体鲤鱼的一种方法。用热休克阻断受精卵第二次减数分裂的方法获得三倍体。用下列热休克参数得到了最佳结果(三倍体率80%-100%;胚胎存活率是对照组的50%-70%):受精后6分钟开始(休克前的孵化温度是20℃),温度为40或41℃,时间为2或1.5分钟。该技术可大规模生产三倍体鲤鱼,因此可以研究工业化养鱼条件下三倍体的性能。  相似文献   

10.
从云南松花坝水库引种太湖新银鱼卵100万粒,其受精率47.3%,经270小时孵化出膜(其中:长途运输22小时,升温孵化118小时),出膜前镜检成形胚胎达41.6万粒,占受精孵的87.9%。全程常温孵化出膜时间迟120小时。本文详细介绍了引种孵化的技术操作要点。  相似文献   

11.
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.  相似文献   

12.
13.
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.  相似文献   

14.
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.  相似文献   

15.
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.  相似文献   

16.
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.  相似文献   

17.
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).  相似文献   

18.
19.
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.  相似文献   

20.
Plasma estradiol-17 (E2), testosterone (T), 17,20-dihydroxy-4-pregnen-3-one (DHP) and 17,20,21-tri-hydroxy-4-pregnen-3-one (20-S) levels were measured by radioimmunoassay (RIA) in white perch (Morone americana) and white bass (M. chrysops) that were induced to undergo final oocyte maturation (FOM) with human chorionic gonadotropin (hCG). Plasma DHP levels increased in females of both species in association with oocyte germinal vesicle migration (GVM) and germinal vesicle breakdown (GVBD) and decreased thereafter. Plasma 20-S levels also increased with oocyte GVM in white bass, but were several-fold lower than DHP levels. Circulating E2 and T levels were greatest during GVM and GVBD in both species and decreased to low levels during oocyte hydration and ovulation. Follicles from white perch and white bass which received a priming injection of hCG in vivo, produced both DHP and 20-S in vitro after exposure to hCG and their oocytes underwent GVBD. Ovarian incubates from unprimed fish of either species produced only E2 and T and their oocytes did not complete GVBD. Oocytes from unprimed bass, but not perch, matured when follicles were exposed to hCG in vitro. Both trilostane and cycloheximide blocked in vitro production of DHP and 20-S and oocyte GVBD by white perch follices. DHP and 20-S were equipotent inducers of FOM in the GVBD bioassay. None of several other structurally-related steroids tested were effective within a physiological range of concentrations. These results indicate a role for DHP and 20-S in the control of FOM in white perch and white bass.  相似文献   

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