首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 62 毫秒
1.
青蛤育苗成败的关键是是否能培养出满足育苗需要的大量优质藻类,而藻类培养并非易事,其中有很多问题需要解决。关于藻类的培养有很多文献可供参考,然而大多有关藻类培养的资料理论性强,技术复杂,难以在大规模生产上应用。本文从生产实际出发,结合藻类培养的实践经验,对青蛤育苗过程中藻类培养的相关技术进  相似文献   

2.
轮虫的室内高密度培养与营养强化   总被引:6,自引:0,他引:6  
随着海水育苗(特别是海水鱼育苗)的发展,轮虫的培养日益受到水产工作者的重视,轮虫培养技术不断进步。尤其是近几年发展起来的生物“包裹”技术,利用轮虫这个活载体,可以将海水鱼幼苗所需的某些营养物质,如二十二碳六稀酸(DHA)、二十碳五稀酸(EPA)、各种维生素等传递给幼苗。这一技术已在欧、美、日等国家的海水育苗场中得到广泛的应用。因此,如何培养出高质量的轮虫,是育苗工作中重要一环。笔者根据近两年来在大黄鱼育苗中的一些体会,将轮虫的培养及营养强化技术作一简单总结,供同行参考。1种源一是利用冬卵(也称休眠卵…  相似文献   

3.
有关轮虫、丰年虫及虎斑猛水蚤等培养技术,前面已做过介绍。本文将扼要叙述淡水蚤状蚤和微型蠕虫的培养方法,其次就日本在饵料生物培养工作中的某些情况谈谈个人浅见,做为“综述”的小结。不妥之处,请读者指正。  相似文献   

4.
随着泥蚶工厂化育苗技术的不断提高,其生产工艺也逐步简便化、规范化。正常情况下出苗密度已达100万~150万颗/m2,但与之配套的藻类培养工艺往往达不到上述规模的需求。这是因为泥蚶繁殖季节处于高温多雨期,尤其在浙南一带,气候闷热,污染机会明显增多,不能顺利进入下级培养,造成在时间和数量上与投喂需求难以吻合。笔者通过近几年的实践,将整个培养过程分为初级、扩大、生产培养三个阶段,初步总结了一套操作简便易行、生产相对稳定、能充分满足育苗需要的方法,介绍如下。1初级培养  包括保种培养和扩种培养。1.1藻种选择选择…  相似文献   

5.
持续稳定培养单细胞藻技术   总被引:4,自引:0,他引:4  
曹丽 《水产科学》1995,14(4):35-37
持续稳定培养单细胞藻技术曹丽(辽宁省海洋渔业开发中心大连116013)关键词:培养,单细胞藻,技术随着栉孔扇贝、海湾扇贝、太平洋牡蛎、魁蚶等品种人工育苗技术的不断发展与完善,育苗室的综合利用,已成为共识。这就要求技术人员能够稳定地提供大量的单细胞藻类...  相似文献   

6.
单细胞藻中含有大量的多聚不饱和脂肪酸(PUFAs)、EPA和DHA,而且多数的单细胞藻具有生长繁殖快、环境适应力强、培养周期短等特点。可实现在人工控制条件下大量培养获得高产的目的,是鱼、虾、贝类等海产品的理想鲜活饵料,藻类培养质量的好坏将直接影响海产品育苗的成败,因此单细胞藻类的培养技术是育苗成功的基础和关键技术。随着人工育苗技术的成熟,单细胞藻类在贝类、虾蟹类、鱼类人工育苗中得到了广泛应用。以下简述一下藻类培养的注意问题:  相似文献   

7.
萼花臂尾轮虫室内规模培养技术   总被引:1,自引:0,他引:1  
郑伟 《水利渔业》2007,27(1):13-13,90
萼花臂尾轮虫具有生长快、繁殖力强、营养丰富等特点,是水产苗种开食和早期培育阶段的优良饵料,可以在淡水中培养。结合轮虫室内高密度培养特点及自身实践经验,对萼花臂尾轮虫室内规模培养技术作简要总结。  相似文献   

8.
海产底栖硅藻的固定化培养研究   总被引:4,自引:0,他引:4  
本文研究了底栖硅藻双点舟形藻(Naviculadisipata)固定在藻酸盐胶珠中的生长情况。研究结果表明,底栖硅藻的固定化培养可以增加藻的生长附着面积,提高藻的生长量。固定化培养后贮存30-360天,藻细胞都能较好地复活生长。因此,固定化培养技术可应用于海产底栖硅藻的扩种生产和保种培养中  相似文献   

9.
近年来,随着水产业的迅猛发展,单胞藻类的培养越来越成为影响海珍品育苗成败的关键因素。基于基层生产单位设施、设备较差,技术力量相对薄弱的实际情况,笔者在多年生产实践的基础上,总结出一套能有效降低生产成本,节省人力、物力的单细胞藻类培养方法,此技术在单胞藻的一、二级培养中做了较大改进。现介绍如下:  相似文献   

10.
刘永  张春芳 《水产养殖》2007,28(4):35-37
在华南地区高温季节主要采用简单实用的降温技术措施,将单胞藻培养水温稳定在其最适温度范围,可以有效地提高培养效果,保证单胞藻稳定、及时的供应。  相似文献   

11.
12.
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   

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.
Growth hormone (GH) and reproduction: a review   总被引:5,自引:0,他引:5  
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.  相似文献   

15.
Protein and amino acid composition of the mantle of juvenile O ctopus vulgaris (Cuvier, 1797) during fasting for 27 days were determined. Average protein content of octopus mantle was of 711.19 ± 46.80 g kg?1 DW, and it decreased with increasing fasting days. The non‐essential amino acids content was higher (486.18 ± 11.08 g kg?1 protein) than essential amino acids (425.82 ± 9.15 g kg?1 protein) at the start of the experiment (unstarved animals). The results suggest that the amino acid profile of the mantle where the most abundant amino acids are Arg, His, Lys, Gly, Leu and Pro could indicate a prolonged fasting condition (>20 days) or poor nutrition of O . vulgaris. This study supports the idea of using mantle for metabolic needs of starved O . vulgaris suggesting that the degradation pathway of amino acids to pyruvate and tricarboxylic acid cycle intermediates was favoured contrary to the degradation pathway of ketogenic amino acids. Special considerations should be taken concerning Thr, Ile, Ser, Ala, Asx (Asp, Asn), Glx (Glu, Gln) (because of their fast intake) and Lys and His (due to their stable contents) during a prolonged period of fasting.  相似文献   

16.
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   

17.
18.
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   

19.
The endemic, anadromous cyprinidChalcalburnus tarichi is the only fish species known to occur in alkaline Lake Van (Eastern Anatolia, Turkey). EightC. tarichi were maintained individually in Lake Van water (17 – 19°C; pH 9.8; 153 mEq·I–1 total alkalinity; 22 total salinity) and tank water samples analyzed for 24 h in 2 to 4 h intervals. At zero time, < 1µM ammonia was present and urea was undetectable in the tank water; at 24 h, total ammonia and urea made up 114±32 and 35±25µM, respectively. Over the experimental period, ammonia-N and urea-N excretion averaged 1041±494 and 607±169moles·kg–1 fish·h–1, respectively. The extent of urea excretion was highly variable between specimens. Uric acid excretion was not detectable.Urea was present at high concentrations in all tissues and plasma (25 – 35moles·g–1·ml–1) of freshly caughtC. tarichi; total ammonia content of the tissues was by a factor of 1.9 (liver) to 3.0 (brain) lower. High arginase activity (2.4±0.2 U·min–1·g–1) was detected in the liver ofC. tarichi but ornithine carbamoylphosphate transferase, a key enzyme of the ornithine-urea-cycle, was absent. Ureagenesis is likely through degradation of arginine and/or uricolysis. High glutamine synthetase activity (11±0.6 U·min–1·g–1) and low ammonia content in brain suggest that, like other teleosts,C. tarichi has an efficient ammonia detoxification in the brain, but in no other tissue.Nitrogenous waste excretion at alkaline pH is discussed. The ability ofC. tarichi to excrete high levels of ammonia at extremely alkaline pH is unique among teleosts studied so far. The mechanism of ammonia excretion under Lake Van conditions remains to be elucidated.  相似文献   

20.
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   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号