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 46 毫秒
1.
对于水产养殖而言,水资源的水质是保证水产养殖业健康良性发展重要因素之一。随着我国社会经济的高速发展,水产养殖业的发展也得到了很大的提升,由于水产养殖业的发展同水资源环境高度密切相关,因而水产养殖业发展是否良性同水质健康与否具有关联性。近年来,由于我国水资源水质条件恶化,对水产养殖造成了较大的负面影响,因此,探究水资源水质条件的改善至关重要。本文从水产养殖水资源水质影响因素出发,分析了水产养殖水质调控技术的运用以及水产养殖异常水质的调控技术运用,以期对水产养殖业水质的改善提供经验借鉴。  相似文献   

2.
《科学养鱼》2008,(4):78
近来水产养殖业迅猛发展,集约化高密度养殖规模日益扩大。根据可持续发展的观点,建立清洁养殖模式,是保持水产养殖健康、稳定发展的重要手段。微生态制剂能有效地净化水质,改善养殖生态环境;抑制病原微生物,提高养殖动物机体免疫力;作为饲料添加剂能促进生长,增进健康。  相似文献   

3.
易力  汪洋 《内陆水产》2007,32(12):35-36
当前,在我国水产养殖业已成为国民经济的主要增长点,如何加强生物防治手段减少病害,发展无公害、可持续发展的绿色水产养殖模式,已成为水产养殖业亟需解决的关键问题。光合细菌是水产养殖的益生菌,在水产养殖中具有净化水质、促进动物生长、减少病害的功能。为了解光合细菌对水产养殖病原菌的直接拮抗功能及机理,笔者采用琼脂纸片扩散法,检测光合细菌对各类微生物的抑菌作用,为光合细菌在实际生产中的推广应用作出指导。  相似文献   

4.
水产养殖中水环境的污染是一个制约水产养殖业健康稳定发展的突出问题。微生物修复技术低碳环保,不但能有效消除污染物、净化水质,而且能够抑制水中有害微生物的繁殖,改善养殖生态环境。文章分析了目前养殖水环境存在的污染问题,概述了微生物修复技术的原理、分类及其在养殖水环境修复中的应用。  相似文献   

5.
当前,如何加强生物防治手段减少病害,发展无公害、可持续发展的绿色水产养殖模式,已成为水产养殖业亟需解决的关键问题。光合细菌是水产养殖的益生菌,在水产养殖中具有净化水质、促进动物生长、减少病害的功能。为了解光合细菌对水产养殖病原菌的直接拮抗功能及机理,笔者采用琼脂纸片扩散法,检测光合细菌对各类微生物的抑菌作用,为光合细菌在实际生产中的推广应用提供参考。  相似文献   

6.
淡水养殖尾水处理研究现状及进展   总被引:4,自引:0,他引:4  
随着我国水产养殖业的快速发展,水产养殖方式从传统粗放养模式向规模化、集约化转变,加上养殖尾水肆意排放,养殖尾水污染日益严重。淡水水产养殖水处理技术的研究受到越来越多的关注。引起水质污染的物质有以下几种:有机物、氨氮、亚硝态氮等。  相似文献   

7.
当前,如何加强生物防治手段减少病害,发展无公害、可持续发展的绿色水产养殖模式,已成为水产养殖业亟需解决的关键问题。光合细菌是水产养殖的益生菌,在水产养殖中具有净化水质、促进动物生长、减少病害的功能。为了解光合细菌对水产养殖病原菌的直接拮抗功能及机理,笔者采用琼脂纸片扩散法,检测光合细菌对各类微生物的抑菌作用,为光合细菌在实际生产中的推广应用提供参考。  相似文献   

8.
水产养殖用的水质和底质调节剂是用于调节和改良水产养殖水质和底质环境条件的一类物质,它包括一些化学产品、生物产品和天然物质。随着我国水产养殖业的快速发展,这类物质的使用量越来越大,类群数量也在逐年增加,但目前我国对这类似药非药性物质的管理几乎是空白,存在着对养殖环境影响和养殖水产品质量安全方面的隐患;如何加强对这类物质的管理已成为当前我国水产养殖业管理中的一个重要课题。  相似文献   

9.
硝化细菌与反硝化细菌及其在水产养殖业的应用   总被引:2,自引:0,他引:2  
近年来,硝化细菌在水产养殖业上的应用越来越引起人们的注意,从而引发了较为广泛的研究。可以说,迄今为止,在大规模集约化的水产养殖生产中,大都使用硝化细菌来净化水质。因为在集约化的水产养殖系统中,经过长期的大量积累,  相似文献   

10.
<正>近年,宁夏水产养殖业快速发展,养殖亩产量增长到500千克以上,养殖生产主要依靠水源水质及大量换水来保障产品质量。随着宁夏水资源日趋紧张,养殖系统因缺水导致水质下降、病害频发,造成药残问题突出,水产品质下降。2016-2017年银川市水产技术推广服务中心联合中国水产科学研究院渔业机械仪器研究所、自治  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.
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   

19.
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   

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