一种大水体太阳能自动增氧装置的研发与试验

研发一种大水体太阳能自动增氧装置,为大水体的缺氧、水体污染提供一种解决方法。太阳能自动增氧装置由太阳能光伏发电系统、检测与智能增氧系统、自动化驱动系统组成。光伏发电系统充分利用太阳能资源,解决了电能消耗问题;检测与智能增氧系统实现了增氧过程中氧溶解浓度检测和智能感应运行;自动化驱动系统通过智能感应信号和电子差速控制系统实现增氧机原地转向、转弯和直行3种运动模式的移动,增加了增氧面积。使用太阳能自动增氧装置增氧试验表明,80 min内1 m水深处溶氧量增加0.79 mg/L,2 m水深处溶氧量增加0.78 mg/L,3m水深处溶氧量增加0.77 mg/L,4 m水深处溶氧量增加0.78 mg/L;改善水质试验表明能有有效提高水体溶氧,降低氮磷含量;养殖试验表明,增加鲤产量35.3%、鲢鳙产量31.2%。     

自主移动式太阳能水车增氧平台设计

针对目前增氧设备不能移动、能源利用单一、自动化及智能化程度低、不具备溶氧检测系统的问题,设计了一种自主移动式太阳能水车增氧平台。通过整体性能的研究分析,设计了增氧平台的整体结构,提出了以超声波测距传感器实时检测和水车左右电机差速控制的自主移动式增氧的实现方法;根据增氧平台工作时间、功率消耗以及阴雨天措施等要求,理论分析了系统太阳能电池板和蓄电池组的配置方法,设计了系统硬件并对各功能模块进行了选型;研究了增氧平台的软件系统以及远程监控端的上位机系统。通过离岸测距实验,验证了增氧平台能够按设定安全距离沿岸边平行移动,并在前方遇到障碍物时进行转向避障,初步实现了增氧平台的自主巡岸移动,扩大了水域的增氧范围。相比传统电力供电固定式增氧设备,增氧平台的增氧范围更大、更灵活,自动化和智能化程度更高。     

射流式增氧机性能研究

为评价射流式增氧机性能,采用SC/T 6009-1999<增氧机增氧能力试验方法>标准,通过清水试验和养殖池塘试验,研究了射流式增氧机在清水中的增氧能力、动力效率,以及实际养殖池塘中上下水层溶解氧变化.结果表明:射流式增氧机对于下层水体具有良好的增氧效果,能使1.5 m水深处溶氧值提高31.0%;利用产生的水流搅拌水体...     

管道式微孔增氧装置的增氧性能研究

为了评价不同进气量和进气压力对管道式微孔增氧装置增氧性能的影响，参照SC/T 6051—2011《溶氧装置性能试验方法》中的标准测试方法，在3个进气压力条件下开展不同进气量的室内清水增氧试验。结果显示：在相同进气量条件下，降低进气压力可取得较好的增氧性能；在相同进气压力条件下，装置的氧质量转移系数和增氧能力随着进气量增大而增大，氧利用率和动力效率则呈下降趋势，但在进气压力为0.2 MPa时，其氧利用率和动力效率下降幅度较缓。综合考虑增氧能力和运行能耗等因素，装置的进气参数可设置为进气压力0.2 MPa、进气量0.064～0.081m³/h,在该条件下增氧能力达到29.79～34.36 g/h,氧利用率达到29.83%～32.32%,动力效率达到7.67～8.31 kg/(kW·h)。研究表明，进气量对装置的增氧性能有较大的影响，合理控制进气量对于提高增氧性能、降低增氧装置能耗具有重要意义。     

移动式叶轮增氧船的研制

本文介绍了一种新型增氧船的工作原理、结构、主要技术参数、使用及经济效益.该船在增氧技术上选用了动力效率最佳的叶轮式增氧机,通过生产实践表明,把叶轮式增氧机装到船上,移动增氧,技术上是可行的,能满足大面积、高密度水产养殖的需要,具有明显的经济效益和社会效益.     

水车式增氧机性能试验研究

研究了水车式增氧机在清水试验中的增氧能力、动力效率以及实际养殖池塘试验中上下水层溶解氧变化。结果表明,水车式增氧机对于水深为1 m以内的养殖水体具有良好的增氧和搅拌效果,开启100 min左右,可使距增氧机10 m、水深0.9 m处水体溶氧值从6.5 mg/L左右上升到8.7 mg/L左右,和上层水体溶氧值趋于一致;运转时可形成一股较大的定向水流,对鳗鱼等喜好水流的鱼类较为适合。但水车式增氧机对<1.5 m的底层水体增氧作用较弱。本研究为水车式增氧机池塘养殖的运用提供了有益的借鉴。     

典型增氧设备在养殖池塘中组合应用的研究

叶轮式、水车式、射流式和曝气式增氧机是目前我国池塘养殖使用的主要增氧设备;由于结构形式和工作原理的不同,4种形式的增氧机有不同的特点和功能。为提高养殖池塘增氧设备的增氧效果,通过增氧设备对养殖池塘水体不同深度增氧效果的试验和养殖池塘自然增氧的试验,分析了4种典型的增氧设备的增氧性能和特点,提出了叶轮式增氧机与耕水机、水车式增氧机与耕水机、水车式增氧机与射流式增氧机以及曝气增氧机与耕水机组合配置使用的混合增氧模式,可以优势互补,充分发挥各种形式增氧设备功能。通过组合使用,达到对养殖池塘水体最大限度的增氧效果的目的。     

工业化养鱼增氧装置的研制

增氧技术是工业化养鱼中的重要措施.本文介绍的装置主要是在中科院煤化所1982年的科研成果—变压吸附制氧机以及增氧塔、水泵和多孔喷射管等技术的基础上研制而成的.这一装置制出的富氧空气的氧纯度可达80%以上,利用强化溶解方法还可使增氧塔出日的水体溶氧达到20毫克/升以上.在养鱼试验中能保证鱼池水体溶氧在8毫克/升以上.     

锥式增氧装置

中国科学院海洋研究所发明了一种锥式增氧装置，在一密闭容器内向水体增氧，有较高的溶解度，没有气体逸出，并且不需要耗能。     

一种新型管式曝气装置的设计与试验

随着水产养殖业逐渐向高密度、集约化方向的发展,为实现氧气(O_2)高效溶解、二氧化碳(CO_2)调控、流态改善等目的,急需研制新型高效曝气装置,开发高效节能的曝气技术。基于气水两相溶解的双膜理论和文丘里原理,设计开发了一种管式曝气装置,经初步试验获得了影响增氧性能的关键技术参数,并以此为基础对曝气装置进行优化设计,研究新型节能增氧技术。试验结果表明,管式曝气装置中影响曝气效果的因素有水面高程(Hw)、缩径(D_1/D_2)、旋混结构、进气口大小、进气量等。水面高程、缩径、进气口越大,进气量越充足,曝气装置的增氧效果越高;而额外增加延长结构和旋混结构后,曝气装置水头损失增大、进气量下降,从而导致增氧效果显著下降。该装置利用额外水流动力实现增氧,是一种高效、节能、经济的新型曝气装置,可为水产养殖提供一种新的增氧方法。     

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 hormone (GH) and reproduction: a review

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.     

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).     

Imported ornamental fish are colonized with antibiotic‐resistant bacteria

There has been growing concern about the overuse of antibiotics in the ornamental fish industry and its possible effect on the increasing drug resistance in both commensal and pathogenic organisms in these fish. The aim of this study was to carry out an assessment of the diversity of bacteria, including pathogens, in ornamental fish species imported into North America and to assess their antibiotic resistance. Kidney samples were collected from 32 freshwater ornamental fish of various species, which arrived to an importing facility in Portland, Oregon from Colombia, Singapore and Florida. Sixty‐four unique bacterial colonies were isolated and identified by PCR using bacterial 16S primers and DNA sequencing. Multiple isolates were identified as bacteria with potential to cause disease in both fish and humans. The antibiotic resistance profile of each isolate was performed for nine different antibiotics. Among them, cefotaxime (16% resistance among isolates) was the antibiotic associated with more activity, while the least active was tetracycline (77% resistant). Knowing information about the diversity of bacteria in imported ornamental fish, as well as the resistance profiles for the bacteria will be useful in more effectively treating clinical infected fish, and also potential zoonoses in the future.     

Effect of iodophor disinfection of non‐hardened Salmo trutta eggs on their bacterial and fungus load

This study investigated the efficiency of iodophor disinfection (135 ppm active iodine for 15–30 min) of non‐hardened Salmo trutta eggs against different groups of bacteria and against fungus. Egg samples were taken from non‐disinfected and from disinfected eggs, microorganisms were cultured on specific nutrient media and their mass was measured by turbidimetric methods. Bacteria and fungus mass of non‐hardened eggs could be reduced but not eliminated by iodophor disinfection with 135 ppm active iodine for 15 min. The extent of reduction was 47–65% (Experiment 1). The efficiency of disinfection increased with disinfection time as the reduction in bacteria and fungus mass was 40–55% after 15 min and 58–74% after 30 min (Experiment 2). Disinfection efficiency of iodophor solution diluted in water (reduction 49–57%) and of iodophor solution diluted in sodium chloride solution iso‐osmolar to the oocytes (reduction 52–61%) was similar (Experiment 3). The reduction in bacteria and fungus mass was persistent as it was 39–72% lower in embryos deriving from disinfected eggs than in embryos deriving from non‐disinfected ones (Experiment 4). In conclusion, the tested disinfection method is inadequate to eliminate pathogens completely but it could positively influence immune defence of eggs and embryos.     

Nitrogenous waste excretion and accumulation of urea and ammonia inChalcalburnus tarichi (Cyprinidae), endemic to the extremely alkaline Lake Van (Eastern Turkey)

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.     

Influence of the antibacterial herbs, Solanum trilobatum, Andrographis paniculata and Psoralea corylifolia on the survival, growth and bacterial load of Penaeus monodon post larvae

The indiscriminate use of antibiotics and chemicals in shrimp hatcheries has led to biomagnification and that in turn could lead to rejection of a whole consignment. The application of the bioencapsulation technique as a tool for curative treatment in shrimp larvae was investigated. Herbs having antibacterial properties such as Solanum trilobatum, Andrographis paniculata and Psoralea corylifolia (methanolic extracts) were bioencapsulated in Artemia and fed to Penaeus monodon post larvae PL 1–25. The post larvae were reared in a medium inoculated with pathogenic bacteria such as Pseudomonas aeruginosa, Staphylococcus aureus, Salmonella typhi and Vibrio sp. Post larvae reared in the non-inoculated water and fed with non-enriched Artemia exhibited 90% survival, highest specific growth rate (12.43%) and reduced bacterial load. P. monodon reared in the bacterial inoculated water and fed with the non-enriched Artemia exhibited the lowest survival (10–30%), specific growth rate (8.42–9.1%) and increased bacterial load (2.86 × 10³ to 3.76 × 10⁵ cfu/g). The methanolic extracts of the herbs helped to increase survival and specific growth rate and reduced bacterial load in the P. monodon culture system. Among the three herbal extracts, P. corylifolia enriched Artemia fed post larvae showed the tendency to higher survival (>50%), growth rate (11.5 averaged) and low bacterial load (1.12 × 10⁵ cfu/g). This revised version was published online in August 2006 with corrections to the Cover Date.