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Ji Hyun Kim Sophie Fridman Hamutal Borochov‐Neori Tamar Sinai Dina Zilberg 《Aquaculture Research》2019,50(2):431-438
Garlic (Allium sativum) has been shown to possess antimicrobial properties against a range of disease‐causing agents, including fish parasites. Our study aimed to investigate the potential use of garlic as a treatment against Cryptocaryon irritans infection, using guppies (Poecilia reticulata) as the fish model. Garlic was freeze‐dried, powdered, and used as it is or as an aqueous extract. The content of allicin, its main active ingredient, was 1.25 mg/g in garlic powder and 0.82 mg/ml in the aqueous extract, as determined by HPLC analysis. Aqueous garlic extract fully immobilized C. irritans theronts and protomonts within 20 and 40 min, respectively, following exposure to 5 µl/ml. Treatment trials were performed, in which infected fish were fed with garlic powder‐supplemented feeds (5%, 10%, or 20% supplementation), bathed in garlic aqueous extract (250 or 500 µl/L) and subjected to a combined treatment which included both feeding and bathing. Results revealed that the tested treatments failed to cure the infection, though reduction in infection intensity on the caudal fin, but not on the gills, was evident following dietary supplementation with 20% of powdered garlic in one of the trials. 相似文献
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Water quality,ecological processes and management procedures in a periphyton biofiltration system in mariculture: A statistical analysis 
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下载免费PDF全文 Ana Milstein Alon Levy Amir Neori Sheenan Harpaz Muki Shpigel Lior Guttman 《Aquaculture Research》2018,49(4):1491-1503
A periphyton biofiltration system of mariculture effluents was studied to identify ecological processes and management procedures that strongly affect the biofilter functioning, in order to attain optimal biomass production and nutrient removal. The multivariate statistical technique of factor analysis allowed reducing the large amount of data available into three main factors. The first factor, which accounted for 49% of the overall data variability, was herein called “biological activity” as it represents the joint effects on the variables measured of photosynthesis, N and P uptake, respiration and decomposition of organic matter. The second and third factors were “autotrophic biomass density” and “nitrite and phosphate uptake/release balance”, which, respectively, accounted for further 20% and 14% of the data variability. A conceptual model, describing the functioning of the periphyton biofilters, revealed a delicate equilibrium among the different processes, whose understanding help to manage the biofilters towards optimal production of periphytic biomass and nutrient removal. Raising flow rate raised the overall nutrient uptake rate but reduced uptake efficiency and diluted nitrifying particles. A reduced flow rate led to sedimentation of organic particles, decomposition and nutrients re‐mineralization. Apparently, control of water flow and nutrient content, periphyton substrate area and the cleaning of the effluent supply system are key management elements for the operation of a periphyton‐based biofilter system that maximizes both periphyton biomass production and nutrient removal. 相似文献
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A pilot-scale system for the intensive land-based culture of abalone was established using an integrated design aimed at eliminating the dependence on external food sources, whilst reducing water requirements and nutrient discharge levels. The system was the first and simplest trial in a series of progressive complexity of the concept of integrated culture of seaweed, abalone, fish and clams in modular and intensive land-based facilities. Relative sizes of the modules, their stocking densities and the rate of nutrient supply were determined based on earlier results to be optimal. Effluents from two abalone (Haliotis tuberculata) culture tanks drained into macroalgae (Ulva lactuca or Gracilaria conferta) culture and biofilter tanks, where nitrogenous waste products contributed to the nutrition of the algae; net algal production from each algal tank was harvested and used to provide a mixed diet for the abalone. Excess algal yield was used elsewhere. The system was monitored to assess productivity and nitrogen partitioning over a year, while improvements were made based on the accumulating results. Total annual N-budgets were combined with mean production figures to determine a suitable ratio of abalone biomass to algal culture vessel productivity, towards commercial application of the concept. The abalone grew on average 0.26% and 0.25% body weight/d in the two culture tanks; reduced growth and increased food conversion ratios (food eaten/biomass gain; w/w) were associated with high summer water temperatures (max. 26.9°C). U. lactuca showed reliable growth and filtration performance (mean production of 230 g fresh weight/m2/d, removing on average 58% of nitrogen supplied). Conversely, G. conferta growth was highly erratic and was deemed unsuitable for the current application. It is estimated that 1 kg of abalone biomass would require food supplied by 0.3 m2 of U. lactuca culture, reducing N inputs required by 20% and N in effluent by 34% when compared to the two organisms grown in monoculture. 相似文献
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A Novel Zero Discharge Intensive Seawater Recirculating System for the Culture of Marine Fish 总被引：2，自引：0，他引：2
Ilya Gelfand Yoram Barak Ziv Even-Chen Eddie Cytryn Jaap Van Rijn Michael D. Krom Amir Neori 《Journal of the World Aquaculture Society》2003,34(3):344-358
Results are presented of a zero‐discharge marine recirculating system used for the culture of gilthead seabream Sparus aurata. Operation of the system without any discharge of water and sludge was enabled by recirculation of effluent water through two separate treatment loops, an aerobic trickling filter and a predominantly anoxic sedimentation basin, followed by a fluidized bed reactor. The fish basin was stocked for the first 6 mo with red tilapia Oreochromis niloticus × O. aureus at an initial density of 16 kg/m3. During this period salinity was raised from 0 to 20 parts per thousand. Then, gilthead seabream, stocked at an initial density of 21 kg/m3, replaced tilapia at day 167 and were cultured for an additional 225 d. Non steady‐state inorganic nitrogen transformations occurred as a result of these salinity changes. After day 210, the system operated at all times with those water quality parameters considered critical for successful operation of mariculture systems, within acceptable limits. Thus ammonia, nitrite, and nitrate concentrations did not exceed 1.0‐mg total ammonia‐N/ L, 0.5‐mg NO2:‐N/L and 50‐mg NO3‐N/L, respectively. Sulfide levels in the fish basin were below detection limits and oxygen > 6 mg/L after the oxygen generator was added at day 315. Ammonia, produced in the fish basin and to a lesser extent in the sedimentation basin, was converted to nitrate in the aerobic trickling filter. Nitrate removal took place in the sedimentation basin and to a lesser extent in the fluidized bed reactor. Sludge, remaining in the sedimentation basin at the end of the experimental period, accounted for 9.2% of the total feed dry matter addition to the system. The system was disease‐free for the entire year and fish at harvest were of good quality. Water consumption for production of 1 kg of tilapia was 93 L and 214 L for production of 1 kg of gilthead seabream. Additional growth performance data of gilthead seabream cultured in a similar but larger system are presented. During 164 d of operation of the latter system, maximum stocking densities reached 50 kgl M3 and fish biomass production was 27.7 kg/m3. Relatively poor fish survival and growth resulted from occasional technical failures of this pilot system. 相似文献
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M. Shpigel A. Marshall I. Lupatsch J. P. Mercer A. Neori 《Journal of the World Aquaculture Society》1996,27(4):435-442
Abstract.— The European abalone Haliotis tuberculata , a valuable macroalgivore, was introduced and acclimated for culture in a land-based facility at Eilat, Israel, on the Red Sea (Gulf of Aqaba). Large quantities of high-protein seaweed ( Ulva lactuca ) are produced there in biofilters used in fish mariculture. Although high water temperatures (25–27 C) inhibited summer growth, and in spite of the high salinity (41 ± 1 ppt). four groups of abalone of different sizes grew more in 1 yr than reported in their natural habitat. This fast growth is attributed to the long period (8 mo, from fall to spring) in which temperatures in Eilat waters are within the optimal range for this species, and to the high protein content of the seaweed. Winter timing of maximal growth as well as reproduction in Eilat was reversed compared with Europe, where they occur in summer. Gametogenesis began in December, and the gonads in most broodstock were spent by May. Haliotis tuberculata appears to have excellent potential for intensive mariculture in Israel. 相似文献
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The rising share of aquaculture in supplying seafood changes the mixture of species in the world's market, because capture fisheries target carnivorous species whereas aquaculture focuses on species that are lower in the food chain. Trophic level correlates with production volume (tons/yr) and with unit value (US$/ton) in aquaculture but not in capture fisheries (FAO's fisheries data). Apparently, sustainability and economics in aquaculture both depend on ecological efficiency, i.e., the use of resources and the production of waste. Species feeding low in the food chain use efficiently the natural resources. Each level up the food chain inflates costs related to the use of resources, the production of waste and the maintenance of water quality. This effect has further repercussions on the economics of aquaculture: (1) cost influences profit and unit price, and (2) price influences demand and market share. The overall ecological efficiency, sustainability and economics of culturing carnivorous fish are improved by growing them in an ecological balance with species from low trophic levels in integrated multi-trophic aquaculture. 相似文献
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