虾塘投饲船载自适应速度投饲系统设计与实现

为了让投饲船能根据实时船速自动调整投饲速率,从而把虾饲料比较均匀地抛撒至沿着虾塘四周的"食道"上,研制了一种根据虾塘四周"食道"而设计的实时船速自动调节投料量的投饲系统.该系统采用超带宽(UWB)定位系统来定位船体的位置,由单片机解算出投饲船的实时行驶速度,根据船速、虾塘"食道"周长和总投饲量计算出投饲船的实时投饲速率...     

梭子蟹单筐养殖自动投饲系统设计与试验

为解决梭子蟹单筐养殖模式下的自动投饲问题,设计了一套轨道式自动投饲系统。自动投饲系统由行走系统、投饲机、供电系统和控制系统组成。在单片机系统的控制下,行车由直流电机驱动在轨道上行走,当行车上的定位传感器感应到养殖筐边沿上的定位识别板后,投饲机对一排养殖筐同时下料。当行车走到轨道末端时,行程开关可控制行车停止前进,避免行车脱轨。试验结果表明:自动投料系统实现了定量定位自动下料,称料误差在0.3 g以内,投料精度为97%,定位识别率为100%。当水位在0.5 m范围内变化时,定位误差小于3.5 cm,满足梭子蟹单筐养殖自动投喂的要求。     

详解渔业投饲机械(下)

<正>三、工厂化养殖自动投饲机1.工作原理在鱼池上方架设跑道式H型钢轨道,导轨的长度和形状可根据现场鱼池的分布做出相应的调整,在每个鱼池的正上方设置相应的定位识别点。该样机使用反射面为80毫米×150毫米的鱼池定位识别板实现系统定位,投饲装置沿轨道行走到识别点后,安装在投饲装置上的超声     

一种水陆两用自动投饵机设计与试验研究

<正>自动投饵机是提高饲料利用率,降低养殖成本的重要设施。为解决小型池塘的投饲浪费,提高工厂化养殖水平,设计研发出一种新型的水陆两用自动投饵机。根据其工作原理,对投饵机的供料装置、高压流体装置、饵料释放装置和控制系统进行了设计与分析,采用高压流体作为供料能源,管道作为输送机构,混料释放仓作为撒料装置,PLC3系统作为控制器,并按要求制作了样机进行投喂试验。结果表明,该投饵机可以实现底部投喂,投饲深度和投饲距离具有可调性,可以满足不同池塘的需求;投饲的同时还具有增氧的作用。较传统投饵机,该投饵机具有减少饲料浪费,优化鱼类摄食环境,减少局部缺氧的优点,适合现代化渔业养殖的推广和应用。     

轨道式自动投饲系统设计与试验

针对工厂化养殖中人工投饲劳动强度大、投饲误差大、不均匀等问题,研究并设计了一种轨道式自动投饲系统。该系统由上料装置、行走装置、投饲装置和控制装置4个部分组成。控制部分以可编程辑控制器(PLC)为核心、触摸屏为人机界面,采用低压气力输送的方式上料,驱动行走小车运行的方式进行饵料输送,控制螺旋下料装置和旋转抛撒盘的方式进行定量、均匀的饵料抛撒。结果显示:可以实现4个养殖池的饵料投喂,6次投喂等待时间设定,行走速度达18.75 m/min,投饲量精度在0.5%~2.2%,投饲速度1 kg/min左右,定位精度110 mm左右。该投饵系统具有投饲精度高、均匀、高效率等特点,可有效提高饲料利用率和降低劳动强度,从而减少工厂化养殖成本。     

多层水槽式工厂化循环水养殖系统智能投饲车设计

为解决多层水槽式工厂化循环水养殖模式中人工投料操作空间局促、劳动强度大、饲料利用率低等缺点,设计了一套基于K60单片机的小微型智能投饲车。该投饲车由循迹小车、投饲装置和控制系统等组成,在特定投饲跑道上行驶,根据红外对管采集的轨道信息和压力传感器采集的饲料信息判别是否投饲或补料,进而实现智能定点定量投饲。初步试验运行结果显示,该投饲车运行稳定可靠,运行速度0. 5～2. 2 m/s,投饲的定位精度误差在2 cm以内,投饲量误差在10 g以内,基本满足设计要求。     

投饲范围可控的自动投饲机研究

为解决水产养殖用投饲机投饲范围固定、投饲不均匀、饲料利用率低及污染严重等问题,提出并研制了基于气力输送和单片机控制的投饲范围可控的自动投饲机.根据其工作原理,对该自动投饲机的供料系统、抛撒系统和控制系统进行了设计,采用气力作为供料能源,喷嘴和凸台组合作为抛撒机构,选用STC90C516RD+作为控制单元.工作过程表明,与传统投饲机相比,该自动投饲机具有结构简单、饲料不易破碎、饲料利用率高、噪声污染小等特点,并可实现对投饲范围的调节和控制,达到预期投饲范围调节和均匀投饲的效果.     

基于摄食声学的投饵系统设计

针对现在船载式投饵机自动化程度低,人工抛撒成本高、劳动强度大、抛撒不均匀,该文提出了一种基于声学的投饵系统设计。该装置利用Labview声信号采集控件通过罗非鱼鱼群喂食时现场的水下声信号识别,监测和分析鱼群摄食情况,分析该鱼群进食欲望,反馈并制定投饲决策,并驱动舵机和电动推杆实现水平和垂直方向的调整,实现投饲点的控制。该设计可实现对投饲现场的声信号采集和分析,实现对养殖的罗非鱼提供投喂决策。以stm32单片机作为核心,设计的投饵控制系统,驱动执行机构完成抛撒饵料动作。这个设计有望改变目前传统人工以手执投料管的形式定量投饵的行业现状,实现养殖鱼饲料的定向按需投喂。     

高密度养殖池塘自动气力投饲机的设计试验

为解决池塘高密度养殖过程中的投饲机承载量小、投饲不均匀、投饲范围小、饲料利用率低等问题,提出一种基于气体输送原理的自动投饲机。根据其工作原理,对投饲机的供料系统、输送系统、抛料系统和控制系统进行了设计与分析,采用气力作为供料能源,管道作为输送机构,撒料盘作为抛料机构,西门子S7-200PLC作为系统控制单元。结果显示,该自动投饲机能同时满足6个池塘的投喂,并能单独控制,满足池塘的投饲需求;投饲距离达20 m,平均投饲速度400 kg/h,破碎率低于0.9%,基本满足设计要求。与传统池塘投饲机相比,该投饲机具有结构简单、操作方便,饲料不易破碎、饲料利用率高等特点,并可实现对投饲量精确调节与控制。     

一种集成自动投饲与排污的鱼类养殖系统

为提高鱼类养殖中投饲和排污的定时、定量精度及节水效果,降低劳动强度,采用新型PLC、螺旋杆送料机构、减速电机、撒料盘、液位传感器、造流器、电动阀、自动双通道排污装置等,参考人工养殖流程设计开发出一套集成自动投饲与排污的鱼类养殖系统,该系统容积1.57 m3,适宜养殖密度低于23 kg/m3.对系统进行了设备性能测试及鱼...     

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).     

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.     

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.