多营养层次生态养殖模式简析

系统介绍了多营养层次生态养殖模式在淡水养殖及海水养殖中的应用与发展,对比了国内外有关该养殖模式发展方向的异同,简述了该养殖模式通过提高物质和空间利用率、改善养殖环境的原理以及在我国推广应用情况,并汇总了我国沿海省份近年来开展该养殖模式选用的品种搭配及产量产值。指出了多营养层次生态养殖模式还存在的问题,对今后发展提出了建议。     

Metal leaching and toxicity of denitrifying woodchip bioreactor outflow—Potential reuse application

The denitrifying woodchip bioreactor is designed to remediate nitrate-rich water, including those produced from aquaculture effluents. Reuse of treated bioreactor outflows in recirculating aquaculture would offer considerable water savings and valuable alkalinity recuperation. However, such bioreactors may leach detrimental wood-bound contaminants, preventing outflow reuse. To determine water reuse potential, woodchip media from two hardwood species (white ash, Fraxinus americana; Norway maple, Acer platanoides) were evaluated for 206 d under a range of operating conditions (start-up, steady-state, reducing conditions, and drying-rewetting cycles) for a spectrum of potentially harmful dissolved contaminants. Aerated outflows also were evaluated for acute and chronic toxicity to the biologically sensitive invertebrate Ceriodaphnia dubia. Dissolved metal leaching subsided within the first few weeks of operation, though initial concentrations of copper and zinc were detected at concentrations of concern. Elevated concentrations of tannins-lignin and total ammonia nitrogen were detected throughout the study and were influenced by operational phase. Acute toxicity was not generally detected, though chronic toxicity was observed during drying-rewetting cycles in the maple outflows. The measured toxicity was not correlated with water chemistry, indicating an additive effect of several toxicants. Overall, significant differences in outflow water quality between ash and maple wood species were negligible. Results indicated that bioreactor outflows may be applicable for aquacultural reuse, though reusing outflows immediately following start-up or restarting after a dry period would not be recommended.     

城市池塘水质时间变化特性--以扬州大学江阳路南校区池塘为例

城市中的池塘是城市水体的重要组成部分,为揭示城市化背景下池塘水体水质的时间变化特性,选取扬州大学江阳路南校区池塘为研究区,对该池塘2018年7月至2019年6月的水质参数蓝绿藻浓度(Phyco)、水温(WT)、溶解氧(DO)、pH与电导率(EC)进行观测,采用变异系数法、单因子水质标识指数法以及多元线性回归法对各参数的变化特性进行评价。结果显示:池塘WT呈季节性变化;观测期间pH变化范围为7.74~9.98,水体呈碱性;DO变化的随机性较强,未表现出明显变化规律;各水质参数变异性及权重从大到小依次为WT>DO>EC>pH;以DO为指标的单因子水质标识指数结果表明:池塘DO达到Ⅲ类水要求的时段占总观测时段的84%;多元线性回归分析结果表明:DO与WT、pH呈正相关,与Phyco呈负相关,Phyco及pH的变化对DO浓度的影响相对于WT大。     

Implementation of an easily reconfigurable dynamic simulator for recirculating aquaculture systems

Methodology of Programmable Process Structures has been implemented and applied for the flexible automatic generation and simulation of Recirculating Aquaculture Systems. First, we implemented and validated the model for a pilot unit, based on short time experiments with Common carp (Cyprinus carpio), utilizing data and functionalities from the literature. Afterwards, starting from this model we generated a hypothetical single tank model of simulated increasing volume, to demonstrate how it supports the simplified, preliminary analysis, design and control of the possible multi-stage systems. We showed that the simulation of a single tank with an appropriately increasing volume makes possible to study the various control strategies, as well as to design the structure and the grading strategy of the multi-stage systems, without an increased combinatorial complexity. In the knowledge of the simulated increasing volume, we determined the volumes of subsequent stages by equidistant partitioning of the rearing time, algorithmically. Considering the available (or planned) tank volumes, this method makes possible to design a multi-stage system that approximately corresponds to the previously optimized single tank model. This conclusion was illustrated by the generation and simulation of the model for the respective multi-stage system.     

水产养殖鱼类生长性状研究进展

生长性状是水产养殖鱼类最重要的经济性状之一,对水产养殖业的发展意义重大。通过以不同的养殖鱼类为对象,大量的研究结果表明,鱼类生长主要受环境、基因,以及基因与环境相互作用的影响,具体为:(1)环境是生长性状调控的外因,其对生长的影响一般呈现出剂量效应的规律。温度、光照、营养等主要环境因子的过量和不足均可能对鱼类生长产生不利影响,因此,寻求最优条件是制定最佳养殖环境的终极目标,人为调控多种环境因子在现代水产养殖业中具有重大的应用潜力。(2)基因是生长性状调控的内因,其对生长的影响很大程度上表现出因果效应的关系。某些基因的单碱基核苷酸多样性、基因结构变异、染色体倍性变化,以及转基因等都表现出对鱼类生长产生统计显著性的影响。鉴于生长是多基因控制的复杂数量性状,寻找主效基因并在选育中加以利用是改良生长性状的重要基础。高通量测序技术在生长相关候选基因的筛选以及辅助分子育种方面展现出强大的优势。(3)基因与环境相互作用的影响主要来自基因型对不同环境条件的适应性,具有特异性和复杂性的特点,因此目前对其量化研究非常有限。但在制定大规模商业育种计划之前,考虑基因与环境相互作用具有重要意义。综上所述,充分理解环境、基因,以及基因与环境相互作用对水产养殖鱼类生长的影响能更好地对其生长性状加以利用,从而最大限度地节约养殖成本和发挥生态效益。     

基于模糊控制的水产养殖环境智能监控系统设计

为实时掌握水产养殖水质和气象环境信息,针对溶氧控制过程中非线性、惯性大和时滞的问题,以循环水流水槽养殖模式为基础,设计了水产养殖环境监测和控制系统。通过PLC对养殖环境中溶氧、pH、温度、湿度、风速、风向、大气压等参数进行信息采集与传输,上位机实时显示环境信息,用模糊算法处理信息,处理后的结果作为PLC的输出传送到变频器中,变频器控制增氧机调节水中溶氧量。结果显示:该系统可实时传输与显示上述参数信息,提供历史数据和环境异常报警功能。模糊控制在调节溶氧过程中超调小、精度高,溶氧偏差±0.4 mg/L,可减少增氧机启停次数、延长设备寿命。监控系统进行实地应用测试,达到预期效果,可在水产养殖中进行推广和应用。     

Immunostimulatory effects of dietary poly‐β‐hydroxybutyrate in European sea bass postlarvae

The stable production of high‐quality fry in marine aquaculture is still hampered by unpredictable mortality caused by infectious diseases during larval rearing. Consequently, the development of new biocontrol agents is crucial for a viable aquaculture industry. The bacterial energy storage compound poly‐β‐hydroxybutyrate (PHB) has been shown to exhibit beneficial properties on aquatic organisms such as enhanced survival, growth, disease resistance and a controlling effect on the gastrointestinal microbiota. However, the effect of PHB on the developing immune system of fish larvae has so far not been investigated. In this study, the effect of feeding PHB‐enriched Artemia nauplii on survival, growth and immune response in European sea bass (Dicentrarchus labrax) postlarvae was examined. Amorphous PHB was administered to 28‐day‐old sea bass postlarvae over a period of 10 days. The survival and growth performance were monitored, and the expression of 29 genes involved in immunity, growth, metabolism and stress‐response was measured. While the expression of the insulin‐like growth factor 1 (igf1), an indicator of relative growth, was upregulated in response to feeding PHB, the larval survival and growth performance remained unaffected. After 10 days of PHB treatment, the expression of the antimicrobial peptides dicentracin (dic) and hepcidin (hep) as well as mhc class IIa and mhc class IIb was elevated in the PHB fed postlarvae. This indicates that PHB is capable of stimulating the immune system of fish early life stages, which may be the cause of the increased resistance to diseases and robustness observed in previous studies.     

Effects of Panax ginseng extract in practical diets for rainbow trout (Oncorhynchus mykiss) on growth performance,immune response and resistance to Yersinia ruckeri

In a preliminary in vitro study, a Panax ginseng extract exhibited an evident antibacterial activity against Yersinia ruckeri and Lactococcus garvieae and affected the respiratory burst and proliferation of rainbow trout Oncorhynchus mykiss leukocytes. Subsequently, the effects of a dietary ginseng extract supplementation on growth, blood biochemical profile, innate immune response and resistance against Y. ruckeri infection were investigated in vivo in rainbow trout juveniles. Four experimental diets were obtained by adding 0.0%, 0.01%, 0.02%, 0.03% of ginseng ethanolic extract to a commercial feed. Each diet was fed to triplicate groups of fish (mean body weight 30.5 ± 0.15 g) at 1% of body weight day^?1 for 10 weeks. The dietary supplementation with ginseng extract did not affect growth performance, feed utilization, biometric traits and fish whole body composition (P > 0.05). No major changes due to graded levels of ginseng extract in the diet were observed in blood biochemical parameters except for increasing plasma triglycerides and non‐esterified fatty acids in fish fed diets including 0.01% and 0.02% of extract (P < 0.05). The innate immune response was barely modulated by the dietary addition of ginseng extract. Serum lysozyme and leukocytes respiratory burst activities were just slightly increased in fish fed all the ginseng extract‐supplemented diets compared with controls, whereas serum antiproteases and leukocyte MPO were not affected (P > 0.05). The dietary administration of ginseng extract induced a reduction in mortality of rainbow trout infected with Y. ruckeri, although no significant differences between treated and control groups were observed (P > 0.05).     

Tracking escaped Atlantic cod (Gadus morhua L.) aggregated around Norwegian farms: Considerations for management strategies

To examine site fidelity and potential for ecosystem impacts, 20 escapee cod (Gadus morhua L.) from fjord‐based cod farms were tagged with acoustic transmitters, released in the vicinity of the same farm, and their subsequent behaviour and survival monitored using a fixed array of acoustic receivers. Most individuals demonstrated high fidelity to their farm where tagged, and this increased during the polar night. Only five individuals (25%) were occasionally detected at another farm (4 km distance), and only three cod (15%) migrated out of the fjord during the 6‐month study period. Vertical movements were consistently greater in the hours around noon than at night, a behaviour inconsistent with that observed for wild fish. A high mortality rate (40%) was observed during the first 4 months post‐release, and actual mortality may have been even higher, limiting the potential for negative ecosystem effects from cod escapees. Findings from this study are used to discuss the development of recapture strategies for minimising potential impacts from cod escapees to ensure sustainable farming activity.     

3种填料对集装箱循环水养殖废水处理的初步研究

为探讨聚丙烯塑料发泡材料(EPP)、悬浮球填料和海绵填料对集装箱循环水养殖废水中细菌吸附性能的差异,以及3种填料挂膜启动和挂膜成熟后对氨氮(NH_4~+-N)、亚硝酸盐氮(NO_2~--N)和硝酸盐氮(NO_3~--N)的净水效果,以集装箱循环水养殖废水为研究对象,采用自然挂膜的方式进行了为期3个月的试验,并对相关指标进行测定。结果显示:EPP填料对养殖废水中细菌的吸附能力最好,另外两种填料对细菌的吸附能力次之并且差异不显著(P0.05);3种填料自然挂膜成熟的时间分别为21 d、26 d和30 d;各填料挂膜成熟后处理高浓度NH_4~+-N养殖废水时,NH_4~+-N浓度与NO_2~--N浓度之间的关系可以用多项式y=ax~2+bx+c进行拟合,NH_4~+-N浓度与NO_3~--N浓度之间的关系可以用对数式y=aln(x)+b进行拟合。研究表明:EPP填料、悬浮球填料和海绵填料均可作为生物填料用于集装箱循环水养殖系统。