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The nitrogen cycle in aquaculture systems and aquarium tanks. Ammonia is built up from fish excretion and uneaten food. Nitrosomonas , a bacterium, converts the ammonia into nitrite, which is converted into nitrate by nitrobacter , another bacterium. During both chemical conversions by the bacteria, H + is released causing a reduction in pH. A reduced pH will change ammonia into
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This technical memorandum describes the protocols and procedures for maintaining a small-scale zebrafish (Danio rerio) operation at the Northwest Fisheries Science Center, Environmental Conservation Division. Detailed descriptions are presented for Zebrafish Module maintenance, spawning, larvae rearing, adult feeding, quarantine procedures, and ge...
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... Clean biofilters biofilters every serve 3 an months. important Turn role off in the maintaining water pump. the Attach nitrogen the cycle hose ( Figure 3 to the sump and Appendix valve and drain B). The the biofilter water in provides sump to the a large green surface tape (above area for the the drain ammonia- to the pump). and nitrite- Open the air bleed metabolizing valve (white bacteria valve (our on biofilters top of the are lid) polystrand on Ocean dual Clear filter filter pads). casing Sudden #1. Attach changes the in hose the to the drain water valve quality on or Ocean chemistry Clear (e.g., filter pH casing or the #1, presence open valve of chlorine) and drain can water kill from the bacteria the filter and (the stop other the filters nitrogen will cycle, also which drain part will way lead down). to the build Unscrew up of the harmful filter lid ammonia (if necessary, and nitrites. use the Therefore rubber mallet it is to important help loosen to keep it). water conditions stable for the bacteria and ultimately the fish. Clean biofilters every 3 months. Turn off the water pump. Attach the hose to the sump valve and drain the water in sump to the green tape (above the drain to the pump). Open the air bleed valve (white valve on top of the lid) on Ocean Clear filter casing #1. Attach the hose to the drain valve on Ocean Clear filter casing #1, open valve and drain water from the filter (the other filters will also drain part way down). Unscrew the filter lid (if necessary, use the rubber mallet to help loosen ...
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... setting up a tank from scratch, set up the tank and allow water to go through the nitrogen cycle before adding the quarantine fish. For the quarantine tank, make system water using Instant Ocean salt and distilled water. Distilled water is used instead of the RO/DI water from the zebrafish room. This reduces chances of cross-contamination by eliminating a shared water source. To encourage and speed up establishment of the nitrogen cycle (Figure 3 and Appendix B), seed the tank’s sponge filter by adding water and bacteria from the Z-Mod’s sponge filter. Next, add seed fish (fish that are no longer needed; e.g., too old to spawn) from the Z-Mod system (they will be euthanized once the quarantine fish arrive). Initially after the tank is set up and the seed fish are added, ammonia levels will be high. Do not be alarmed; it takes time for the bacteria to grow and start the nitrogen cycle. Slowly, ammonia levels should go down once the bacteria are growing. Ideally, set up the tank 4–6 weeks before the quarantine fish arrive. This should be enough time for the sponge filter to build a good population of bacteria, which will control ammonia and nitrite ...
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... bacterial growth inside the filter case. Let the dirty water drain out of the valve. Remove the hose and close the valve once the water has drained. Wring excess bacteria from the filter pads in the bucket of system water. Removing the excess bacterial growth will allow water to flow through the filters efficiently, while the remaining population of ammonia-metabolizing and nitrite-metabolizing bacteria will continue the nitrogen cycle (Figure ...
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... Source of the water: It is necessary to filter incoming water for particles and contaminants (such as chlorine). 4. Hardness and alkalinity: Hardness is the amount of cations in the water and can have interactions with other water parameters or disease treatments. Alkalinity is the buffering capacity of the water (resists changes in pH) and is related to the amount of bicarbonate in the water. 5. The nitrogen cycle (Figure 3): Ammonia and nitrite are toxic to the fish; nitrate is toxic at very high concentrations (which is why water changes are important). Nitrosomonas and nitrobacter—bacteria that convert ammonia and nitrite—remove the buffering capacity (alkalinity) so the pH will naturally go down. Under low pH conditions, ammonium (NH 4 +) will accumulate, as the nitrosomanas cannot convert this ion. An increase in pH will cause nontoxic ammonium to convert to toxic ammonia. The nitrogen cycle (nitrosomonas and nitrobacter) takes time to establish (4–6 weeks). The reaction is aerobic, so the biological filter must not become anaerobic. Also the bigger the surface area of the filter, the higher the fish capacity the system can support. 6. Filtration: This is required for closed systems. There are three parts to filtration. • Biological filters grow bacteria for the nitrogen cycle. Sudden changes in water quality, therapeutics, and antibiotics can destroy the biofilter. Examples of biofilters are foam, floss, and gravel (they provide surface area for bacteria). • Mechanical filtration removes particulate matter. Examples are foam, filter floss, and gravel (1/4–1/8 inch diameter). • Chemical filters remove small molecular weight compounds. Examples are activated carbon, dolomite, zeolite, ion exchangers, and peat moss (but it also lowers pH). 7. Water sterilization: It is important to remove pathogens from the water source in flow through systems or in closed recirculating systems. Water should be UV or ozone sterilized. 8. Water changes: They are helpful in diluting waste products (e.g., nitrate) and correcting the pH level. 9. Carrying capacity of the system: The number of fish sustainable in a closed system is determined by the amount and capabilities of filtration. 10. Chlorine (and chloramines): It is toxic to fish. Chlorine can be removed by sodium thiosulfate, allowed to dissipate with time, aeration or agitation (to speed release), or with an activated carbon filter. 11. Other toxicants: Toxicants such as pesticides, fertilizers, metals, gases, and smoke affect the health of the fish. 12. Change is not good: Sudden changes in water quality stress the fish and can have detrimental effects on biological ...
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... Make a the bleach bleached solution embryos in a 250-ml are 24–48 beaker hpf, by they adding should 100 be μl manually of 5.25% dechorionated sodium as bleaching hypochlorite will (bleach) cause the to 170 chorions ml of to system become water. tougher. Use Keep a pipette in mind to transfer that even up to bleaching 30 embryos does to not guarantee the bleach that solution. no diseases Keep will the embryos be transferred in the (Appendix solution for D: 2 min Zebrafish while Diseases). occasionally swirling the beaker to allow the entire surface area of the chorions to come in contact with the bleach solution. With a clean pipette, transfer the embryos from the bleach solution to a 250-ml beaker of clean system water. Swirl the embryos in the system water. Repeat the wash in system water one more time, then transfer the embryos back into petri dishes with fresh system water. When the bleached embryos are 24–48 hpf, they should be manually dechorionated as bleaching will cause the chorions to become tougher. Keep in mind that even bleaching does not guarantee that no diseases will be transferred (Appendix D: Zebrafish Diseases). Adding Several a things new aquaculture should be considered system is to an minimize opportunity the to spread make of a fresh pathogens start at to establishing the new a colony system with and to minimal monitor amounts the health of pathogens. of a larger colony. Since a Typically, new system a new will share aquaculture the same system space is as the old seeded one, by it transferring is highly unlikely several that tanks the of new healthy system young will be fish kept from entirely the old pathogen system to free. the new However, it is system. ideal to The reduce introduction the transfer of fish of pathogens to the new between system will systems. produce In the ammonia, unlikely which event will of a start disease the outbreak, nitrogen cycle at least (Figure 3) both systems and grow will the not ammonia- succumb to and a massive nitrite-metabolizing die-off or other bacteria deleterious in the sponge effect. biofilters. However, adding fish to the new system will carry over any pathogens from the old system. To eliminate transfer of pathogens to the new system, seed a system without using fish by adding large amounts of fish food to the new system daily. This should build up ammonia and start the nitrogen cycle. However, it will also take longer to achieve a good population of ammonia- and nitrite-metabolizing bacteria in the sponge biofilters without fish. Several things should be considered to minimize the spread of pathogens to the new system and to monitor the health of a larger colony. Typically, a new aquaculture system is seeded by transferring several tanks of healthy young fish from the old system to the new system. The introduction of fish to the new system will produce ammonia, which will start the nitrogen cycle (Figure 3) and grow the ammonia- and nitrite-metabolizing bacteria in the sponge biofilters. However, adding fish to the new system will carry over any pathogens from the old system. To eliminate transfer of pathogens to the new system, seed a system without using fish by adding large amounts of fish food to the new system daily. This should build up ammonia and start the nitrogen cycle. However, it will also take longer to achieve a good population of ammonia- and nitrite-metabolizing bacteria in the sponge biofilters without ...
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... Make a the bleach bleached solution embryos in a 250-ml are 24–48 beaker hpf, by they adding should 100 be μl manually of 5.25% dechorionated sodium as bleaching hypochlorite will (bleach) cause the to 170 chorions ml of to system become water. tougher. Use Keep a pipette in mind to transfer that even up to bleaching 30 embryos does to not guarantee the bleach that solution. no diseases Keep will the embryos be transferred in the (Appendix solution for D: 2 min Zebrafish while Diseases). occasionally swirling the beaker to allow the entire surface area of the chorions to come in contact with the bleach solution. With a clean pipette, transfer the embryos from the bleach solution to a 250-ml beaker of clean system water. Swirl the embryos in the system water. Repeat the wash in system water one more time, then transfer the embryos back into petri dishes with fresh system water. When the bleached embryos are 24–48 hpf, they should be manually dechorionated as bleaching will cause the chorions to become tougher. Keep in mind that even bleaching does not guarantee that no diseases will be transferred (Appendix D: Zebrafish Diseases). Adding Several a things new aquaculture should be considered system is to an minimize opportunity the to spread make of a fresh pathogens start at to establishing the new a colony system with and to minimal monitor amounts the health of pathogens. of a larger colony. Since a Typically, new system a new will share aquaculture the same system space is as the old seeded one, by it transferring is highly unlikely several that tanks the of new healthy system young will be fish kept from entirely the old pathogen system to free. the new However, it is system. ideal to The reduce introduction the transfer of fish of pathogens to the new between system will systems. produce In the ammonia, unlikely which event will of a start disease the outbreak, nitrogen cycle at least (Figure 3) both systems and grow will the not ammonia- succumb to and a massive nitrite-metabolizing die-off or other bacteria deleterious in the sponge effect. biofilters. However, adding fish to the new system will carry over any pathogens from the old system. To eliminate transfer of pathogens to the new system, seed a system without using fish by adding large amounts of fish food to the new system daily. This should build up ammonia and start the nitrogen cycle. However, it will also take longer to achieve a good population of ammonia- and nitrite-metabolizing bacteria in the sponge biofilters without fish. Several things should be considered to minimize the spread of pathogens to the new system and to monitor the health of a larger colony. Typically, a new aquaculture system is seeded by transferring several tanks of healthy young fish from the old system to the new system. The introduction of fish to the new system will produce ammonia, which will start the nitrogen cycle (Figure 3) and grow the ammonia- and nitrite-metabolizing bacteria in the sponge biofilters. However, adding fish to the new system will carry over any pathogens from the old system. To eliminate transfer of pathogens to the new system, seed a system without using fish by adding large amounts of fish food to the new system daily. This should build up ammonia and start the nitrogen cycle. However, it will also take longer to achieve a good population of ammonia- and nitrite-metabolizing bacteria in the sponge biofilters without ...
Citations
... When aquatic animals excrete waste, ammonium (NH 4+ ) and ammonia (NH 3 ) are formed. The latter is extremely toxic, causing damage to the delicate gill tissue at relatively low levels (Moe 1992, DeTolla et al. 1995Johnston and Jungalwalla 2005;Linbo 2009). The toxicity of the compound also increases in waters that display higher pH (more alkaline waters), temperature and salinity (Johnston andJungalwalla 2005, Nickum et al. 2004). ...
Snowy Hydro Limited received approval in 2020 to construct a new large-scale pumped hydro-electric storage and generation scheme (Snowy 2.0), to increase hydro-electric capacity within the existing Snowy Mountains Hydro-electric Scheme. This will involve the connection of the existing Talbingo and Tantangara reservoirs via a series of underground pipes and an underground power generation station. Water will be transferred in both directions between the reservoirs, which are in separate river catchments.
The Arthur Rylah Institute for Environmental Research has been engaged by Snowy Hydro to provide specialist advice that can inform the selection of options and preparation of various aquatic Management Plans required as part of the New South Wales (NSW) and Commonwealth approvals for the Snowy 2.0 project. This report details a captive breeding strategy for Stocky Galaxias (Galaxias tantangara). It outlines the known requirements and identifies the key knowledge gaps required to establish a captive population and breeding program for the species should this be attempted in the future. Given the long-term nature of such an endeavor, the value and relevance of this strategy will extend beyond the Snowy 2.0 Management Plans.
... Once the bio-filter is established and stable, measurements can be done weekly instead of daily, if all other parameters are acceptable and fish behaviour is normal. To reduce nitrate levels, routine water changes are required (Linbo, 2009). ...
... The nitrogen cycle in aquaculture systems and aquarium tanks.(Linbo, 2009) CHAPTER 3: RESULTS AND DISCUSSION ...
One of the major constraints in South African warm-water aquaculture is low water temperatures associated with cold weather and winter months. The extreme cost of heating to raise the water temperature during these times is generally unfeasible; and for this reason, warm-water aquaculture is predominantly confined to one 6-month summer production cycle per year. Geothermal hot springs have thus been proposed as a viable alternative heat source for the support of warm-water aquaculture all year round. A geothermal hot spring at the Brandvlei Correctional Facility in Worcester in the Western Cape, was identified as the start site for this 12-month project. The spring water at Brandvlei is approximately 60°C and emerges from the ground at 126 L/s and complies with all water drinking standards. The overall aim of the project was to investigate a suitable method to use the heat from the Brandvlei geothermal spring to support the warm-water aquaculture of Nile tilapia, with focus on renewable energy, and creating food security and skills development opportunities. The specific aims were to firstly develop an appropriate method to harness the geothermal heat to support tilapia aquaculture; to then determine the costbenefit of utilising geothermal heat for aquaculture; and to also provide a SWOT analysis evaluating the potential use of the test-system for fish production and skills development. The project involved the design and installation of two separate single-tank recirculating aquaculture systems of 10 000 L each, that individually maintained a water temperature of 28°C for optimum Nile tilapia aquaculture. The ‘control’ system included a conventional heating method (a heat pump) and was referred to as the HP system; and the ‘test’ system included a heat exchanger which transferred heat from the Brandvlei geothermal spring to the fish-tank system’s water and was referred to as the HX system. A kilowatt meter was included in each system to monitor and compare the electricity usage of the systems separately. From the power consumption records it was seen that the HX system used significantly less power than the HP system at any given time. Records for monthly power usage for the period from November 2021 to April 2022, showed that the cost savings percentage was as high as 55.7% for the coldest month (April) when comparing the daily power usage for the HX system to that of the HP system. It was seen that the average monthly power usage of the HP system had a strong negative correlation with the minimum average monthly temperature for Worcester, whereas the power usage for the HX system appeared to be relatively consistent over the months, having only a moderate negative correlation with minimum temperature. The power consumption records and historical temperature records for ambient temperature in Worcester were used in simple linear regression analyses to make predictions for what the systems may have cost to run for the full previous year of 2021. In terms of power usage, predictions indicated that the HX system would use 57.8% less power than the HP system for the full year of 2021. In terms of the average monthly cost for running and heating the 10 000 L systems, it was predicted that for 2021 it would cost between R3 838.50 and R3 423.00 monthly for the HP system and between R1 445.60 and R1 411.25 monthly for the HX system. Depending on the electricity user tariffs, this could be a cost-savings percentage of between 57.8 and 63.2% in favour of the HX system. It is expected that in colder weather or in winter months, the cost savings percentage would be higher to a point, and then the HP system would most likely need insulation to keep temperatures from dropping below 28°C. Fish were stocked successfully in both systems, however, due to this being a 12-month project, a full growth cycle (±6 months) was not possible within this project’s timeframe, but the co-management plan between Stellenbosch University and the Department of Correctional Services was established to ensure continued maintenance of the fish and the system until harvest at ±6 months. Based on the results, it was concluded that geothermal energy may be a viable solution to producing warmwater fish species all year around feasibly, as long as there is a good management strategy in place. This project provides a system design that can be applied at other hot springs in South Africa, which in turn will promote the development of the aquaculture sector while also creating food security and skills development opportunities. Besides the cost savings advantage, another major benefit of using a heat exchanger for geothermal aquaculture is that the geothermal water does not come into contact with the water of the aquaculture system. This means that even geothermal hot springs with poor water quality can be used, as it would just be the heat that would be harnessed from these springs. A limitation that was identified during the project was with regard to the data collection, as the power consumption meters only recorded the total power used for each system each day and did not record at smaller intervals. It was therefore not possible to obtain accurate estimates of running and heating power consumption separately. A recommendation for improvement or for future studies would thus be to either set the meters to record power used for heating only, or to find a power recording programme that would record power usage at minute intervals. Installing a roof or cover over the systems is also recommended to protect the systems and managerial staff from the harsh elements of sun and rain during extreme weather. A remote alarm system would also be useful for notifying the manager and core project members about any system failure on their cell phone, as a delayed response to system issues can result in mass fish mortalities
... Because test 1 had the longest operation time (approximately 7 days), the membrane separation might cause compound accumulation in the feed tank. Moreover, the complicated matrixes of the used FS (aquaculture wastewater) in tests 2 and 3 might have caused membrane fouling (Li et al., 2020;Lotfi et al., 2018;Wall, 2013;Linbo, 2009). In particular, the ammonia fluxes are a function of the initial concentration of the FS, and the ammonia transport mechanism differs upon the surface density of the membrane (Ortega-Bravo et al., 2016). ...
This paper describes the fabrication, modification, and evaluation of the performance of thin-film composite (TFC) forward osmosis (FO) membranes for lab-scale aquaculture wastewater recovery using various fumed silica (SiO2) nanoparticles. The active polyamide (PA) layers of these membranes were novelly modified using different types of pretreated SiO2 nanoparticles [virgin SiO2, dried SiO2, and 3-aminopropyltriethoxysilane (APTES)-modified SiO2] and concentrations (0.05, 0,1, 0,2, and 0.4 wt.%) to improve the membrane hydrophilicity with minimum particle agglomeration. Results show that the APTES-SiO2 modified membrane had the highest water flux and selectivity, followed by the dried-SiO2 modified membrane. The APTES coupling agent notably reduced the SiO2 aggregation on the membrane surface and improved membrane hydrophilicity. Consequently, high permeate flux and an acceptable reverse solute flux were observed. The optimal SiO2 concentration for PA modification was 0.1 wt.% for all the nanoparticle types. The virgin and APTES-SiO2 modified membranes were used for aquaculture wastewater recovery. The water recovery rate reached 47% in 84 h when using the APTES-SiO2 modified membrane, while it reached only 26% in 108 h when using the virgin membrane. With a suitable design of the filtration apparatus and choice of draw solution (DS), the prepared novel TFC-FO membrane containing APTES-modified SiO2 can be used for recycling aquaculture wastewater into the DS, which can then be reused for other purposes.
... Debido a su relevancia como modelo biológico, la instalación de laboratorios especializados en la crianza y mantenimiento de esta especie se incrementó en 1994 tras la publicación del "The Zebrafish Book. A Guide for the Laboratory Use of Zebrafish (Danio rerio)" considerado una referencia mundial en diversos ámbitos científicos (Monte Westerfield, 1994) y cuyos conocimientos han sido reforzados por el libro "Zebrafish: a practical approach" (Christiane Nüsslein-Volhard, 2002) y un amplio número de publicaciones relevantes reportadas a la fecha (Barney Reed, 2011;Bilotta et al., 1999;Linbo, 2009;Matthews, 2002). ...
... Los compuestos nitrogenados son un factor muy importante y se pueden encontrar en diferentes formas en el medio. Los desechos que son expulsados por los peces y el alimento que no ha sido consumido se descomponen y producen amoniaco (NH3), un compuesto toxico para los peces (Barney Reed, 2011;Linbo, 2009). Las Nitrosomonas y las cianobacterias son bacterias que consumen y procesan este amoniaco (NH3) y generan nitrito (NO2 -) como subproducto, el cual sigue siendo tóxico para los peces, aunque en menor grado que el amoniaco. ...
... Su reproducción es sexual y ovípara con fertilización externa. La hembra, al recibir los estímulos del macho, inicia el desove e induce la expulsión del esperma por el macho en el agua lo que favorece la fertilización de los huevecillos (Lawrence, 2007;Linbo, 2009). Las hembras llegan a poner hasta 200 huevecillos por desove cada segundo o tercer día (Rocha et al., 2002;Spence and Smith, 2005;Spence, 2007). ...
La gamificación es la inserción de elementos de los juegos en la enseñanza con el fin de
potenciar la motivación y, por consiguiente, optimizar el desempeño de los estudiantes.
La gamificación en Ciencias Naturales ha demostrado resultados positivos, como la
identificación de factores motivacionales y potencializar el aprendizaje de los alumnos
con el uso de tecnología (Rodríguez & Avendaño, 2018); así como el desarrollo de
valores y habilidades sociales (Segura Jiménez, 2019).
Este trabajo representa un esfuerzo para integrar a la Educación Básica Pública nuevas
metodologías para la enseñanza y el aprendizaje que involucren el uso de tecnologías
dentro y fuera del aula. La educación en las escuelas públicas no puede demorar más
tiempo en incorporar las TIC’s y nuevas metodologías de comprobada eficacia en sus
planes de trabajo con el propósito de disminuir la brecha que divide a los países ricos y
mejor desarrollados en educación de aquellos que van en vías de desarrollo (UNESCO,
2005), así como fomentar el desarrollo de docentes y alumnos.
... Purified mRNAs were diluted in sterile distilled water at concentrations enabling microinjection of 10 or 100 pg in a 4 nl volume into early cleavage stage embryos of AB strain zebrafish using a Harvard Apparatus PL100 injection system (Holliston, MA, USA). The zebrafish broodstock was maintained according to the policies of the US Department of Commerce and the Public Health Service, conforming to the standards of the National Academy of Sciences' Guide for the Care and Use of Laboratory Animals (National Research Council, 2011;Linbo, 2009). At mid-gastrulation, viable embryos were transferred to 100 mm Petri dishes in 40 ml zebrafish system water and incubated at 28.5°C. ...
... The relative expression of target genes was normalized using the averaged values of two reference genes, wdtc1 and ef1α (Edmunds et al., 2014). For quantification of zebrafish nkx genes, hearts were dissected from 1 month old juveniles and >1 year old adults (AB strain) reared using standard procedures according to the animal care policy of the US Department of Commerce (Linbo, 2009), and was RNA extracted and processed for qPCR as above for salmon cardiac RNA. ...
Cardiac remodeling results from both physiological and pathological stimuli. Compared to mammals, fish hearts show a broader array of remodeling changes in response to environmental influences, providing exceptional models for dissecting the molecular and cellular bases of cardiac remodeling. We recently characterized a form of pathological remodeling in juvenile pink salmon (Oncorhynchus gorbuscha) in response to crude oil exposure during embryonic cardiogenesis. In the absence of overt pathology (cardiomyocyte death or inflammatory infiltrate), cardiac ventricles in exposed fish showed altered shape, reduced thickness of compact myocardium, and hypertrophic changes in spongy, trabeculated myocardium. Here we used RNA sequencing to characterize molecular pathways underlying these defects. In juvenile ventricular cardiomyocytes, antecedent embryonic oil exposure led to dose-dependent up-regulation of genes involved in innate immunity and two NKX homeobox transcription factors not previously associated with cardiomyocytes, nkx2.3 and nkx3.3 Absent from mammalian genomes, the latter is largely uncharacterized. In zebrafish embryos nkx3.3 demonstrated a potent effect on cardiac morphogenesis, equivalent to nkx2.5, the primary transcription factor associated with ventricular cardiomyocyte identity. The role of nkx3.3 in heart growth is potentially linked to the unique regenerative capacity of fish and amphibians. Moreover, these findings support a cardiomyocyte-intrinsic role for innate immune response genes in pathological hypertrophy. This study demonstrates how an expanding mechanistic understanding of environmental pollution impacts - i.e., the chemical perturbation of biological systems - can ultimately yield new insights into fundamental biological processes.
... Physicochemical parameters of the water were controlled and adjusted to be as follows: temperature 28°C; pH: 7.5 (recommended by Brand et al. 32 as the best pH to rear and breed zebrafish and to maintain the biofilters 34 ) adjusted using 1 M Na 2 CO 3 33 ; and conductivity 1043-1094 lS cm -1 . 35 These regular tanks were filled leaving 1.5 cm of air space between the water surface and the tank lid to let fish gulp air. 36 The tanks were set up in an isolated room with the room temperature set 1°C higher than the tank water temperature. ...
... Glass beakers of 1000 mL were placed in the regular tanks filled halfway with tap or distilled water. Six-month-old zebrafish, 33,35,40 selected as consistent spawners 47 were used for the experiments. The age of the fish was determined from the time of hatching of the eggs. ...
... Zebrafish breeding, embryo collection, and fecundity and FR determination A 1 L mating cage 67 with a screen of 2 mm 2 porosity, which had been provided with plastic plants 32 was setup into a regular tank (of either 5 or 12 L) equipped with a submersible heater, aerator, and thermometer (filled with system water). One healthy male and female zebrafish (ratio 1:1, a pairwise crossing spawning 36 ), segregated 1 week before mating session, 35 were transferred to the mating cage late in the afternoon (6:00 p.m. *15 h before spawning) the day before spawning. Genders were housed in different chambers separated by a transparent plastic divider of the mating cage and left there overnight. ...
Sperm quality is an important topic in general health, chemotherapy, and gamete preservation technology. Fatty acid (FA) composition of membranes, which is influenced by the diet, plays key roles in sperm biology and quality. Dietary supplementation with natural products can be used as a technique to screen potential agents to protect, modify, and recover sperm quality. In this study, zebrafish (male [♂-ZF] and female [♀-ZF]) were fed a single cultivar olive oil (OO) bioencapsulated in Artemia. OO-treated ♂-ZF had higher (p < 0.05) sperm density and motility compared to the Artemia nauplii (AN). A significant difference was also observed in follicle abundance at different stages of gametogenesis, and a nonsignificant increase in total fecundity between OO-treated ♀-ZF and the AN, although in OO-treated ♀-ZF, mature follicles had a smaller diameter. A higher fertility rate (FR) was observed in OO-treated pairs compared to the other groups. Hatching in the OO-treated fish was accelerated, although no significant differences could be found in terms of hatching rate (HR) and embryo/larval survival rate (SR). These findings in FR, HR, and SR were also confirmed in male and female replacement mating trials. Taken together, this study shows that altering the FA ratios in the diet has a clear impact on several reproductive parameters in the zebrafish, adding new information about the nutritional requirement of this model species.
... Adult wild-type (AB) zebrafish were maintained and spawned at NOAA's Northwest Fisheries Science Center in control water following standard institutional protocols for animal care and husbandry. 29 Eggs were collected each morning and incubated in control water until 2.5 h postfertilization (hpf). Normally developing embryos were then transferred to glass Petri dishes (15 × 60 mm) and exposed to 10 mL of either control water or highway runoff for 48 h at 28.5°C ...
Urban stormwater runoff is a globally significant threat to the ecological integrity of aquatic habitats. Green stormwater infrastructure methods such as bioretention are increasingly used to improve water quality by filtering chemical contaminants that may be harmful to fish and other species. Ubiquitous examples of toxics in runoff from highways and other impervious surfaces include polycyclic aromatic hydrocarbons (PAHs). Certain PAHs are known to cause functional and structural defects in developing fish hearts. Therefore, abnormal heart development in fish can be a sensitive measure of clean water technology effectiveness. Here we use the zebrafish experimental model to assess the effects of untreated runoff on the expression of genes that are classically responsive to contaminant exposures, as well as heart-related genes that may underpin the familiar cardiotoxicity phenotype. Further, we assess the effectiveness of soil bioretention for treating runoff, as measured by prevention of both visible cardiac toxicity and corresponding gene regulation. We find that contaminants in the dissolved phase of runoff (e.g., PAHs) are cardiotoxic, and that soil bioretention protects against these harmful effects. Molecular markers were more sensitive than visible toxicity indicators, and several cardiac-related genes show promise as novel tools for evaluating the effectiveness of evolving stormwater mitigation strategies.
... Wild-type (AB) zebrafish were cultured and spawned at the NWFSC using previously described methods (Linbo, 2009). Groups of embryos (n = 15) were distributed at 2-4 h post-fertilization (hpf) into triplicate glass petri dishes (60 × 15 mm) and exposed to 10 mL highway runoff (exposed) or embryo rearing medium (controls). ...
Urban stormwater contains a complex mixture of contaminants that can be acutely toxic to aquatic biota. Green stormwater infrastructure (GSI) is a set of evolving technologies intended to reduce impacts on natural systems by slowing and filtering runoff. The extent to which GSI methods work as intended is usually assessed in terms of water quantity (hydrology) and quality (chemistry). Biological indicators of GSI effectiveness have received less attention, despite an overarching goal of protecting the health of aquatic species. Here we use the zebrafish (Danio rerio) experimental model to evaluate bioinfiltration as a relatively inexpensive technology for treating runoff from an urban highway with dense motor vehicle traffic. Zebrafish embryos exposed to untreated runoff (48-96h; six storm events) displayed an array of developmental abnormalities, including delayed hatching, reduced growth, pericardial edema, microphthalmia (small eyes), and reduced swim bladder inflation. Three of the six storms were acutely lethal, and sublethal toxicity was evident across all storms, even when stormwater was diluted by as much as 95% in clean water. As anticipated from exposure to cardiotoxic polycyclic aromatic hydrocarbons (PAHs), untreated runoff also caused heart failure, as indicated by circulatory stasis, pericardial edema, and looping defects. Bioretention treatment dramatically improved stormwater quality and reversed nearly all forms of developmental toxicity. The zebrafish model therefore provides a versatile experimental platform for rapidly assessing GSI effectiveness.
... Embryos of zebrafish AB strain were obtained from adults maintained using conventional zebrafish animal care protocols (Linbo, 2009). Embryos were exposed at either 4-6 h (sphere to shield developmental stage) or 28-30 h post-fertilization (hpf). ...
... In control embryos, rates of edema were low enough to provide only a single group with edema (n = 30), while embryos without edema were pooled into five replicate groups (n = 30 each). The new replicate groups were transferred to clean water, incubated at 28.5 • C in 100-mm Petri dishes until feeding stage and then raised until juvenile stage (2 weeks post-fertilization) as detailed elsewhere (Linbo, 2009), with mortality assessed daily. At 2 weeks post-fertilization, fish were anesthetized, assessed for morphological defects, and lengths measured. ...
The 2010 Deepwater Horizon disaster in the Gulf of Mexico was the largest oil spill in United States history. Crude oils are highly toxic to developing fish embryos, and many pelagic fish species were spawning in the northern Gulf in the months before containment of the damaged Mississippi Canyon 252 (MC252) wellhead (April-July). The largest prior U.S. spill was the 1989 grounding of the Exxon Valdez that released 11 million gallons of Alaska North Slope crude oil (ANSCO) into Prince William Sound. Numerous studies in the aftermath of the Exxon Valdez spill defined a conventional crude oil injury phenotype in fish early life stages, mediated primarily by toxicity to the developing heart. To determine whether this type of injury extends to fishes exposed to crude oil from the Deepwater Horizon - MC252 incident, we used zebrafish to compare the embryotoxicity of ANSCO alongside unweathered and weathered MC252 oil. We also developed a standardized protocol for generating dispersed oil water-accommodated fractions containing microdroplets of crude oil in the size range of those detected in subsurface plumes in the Gulf. We show here that MC252 oil and ANSCO cause similar cardiotoxicity and photo-induced toxicity in zebrafish embryos. Morphological defects and patterns of cytochrome P450 induction were largely indistinguishable and generally correlated with polycyclic aromatic compound (PAC) composition of each oil type. Analyses of embryos exposed during different developmental windows provided additional insight into mechanisms of crude oil cardiotoxicity. These findings indicate that the impacts of MC252 crude oil on fish embryos and larvae are consistent with the canonical ANSCO cardiac injury phenotype. For those marine fish species that spawned in the northern Gulf of Mexico during and after the Deepwater Horizon incident, the established literature can therefore inform the assessment of natural resource injury in the form of potential year-class losses.
... A zebrafish breeding colony (wild type AB) was maintained using routine procedures (Linbo, 2009). Fertilized eggs were collected in water adjusted to a conductivity of approximately 1500-1600 lS cm À1 , pH 7.5-8 with Instant Ocean salts (''system water''). ...
Crude oils from different geological formations vary in composition, yet most crude oils contain a polycyclic aromatic hydrocarbon (PAH) fraction that would be expected to produce cardiotoxic effects in developing fish. To determine whether different crude oils or PAH compositions produce common or distinct effects, we used zebrafish embryos to directly compare two crude oils at different states of weathering. Iranian heavy crude oil (IHCO) spilled in the Yellow Sea following the 2007 Hebei Spirit accident was compared to the intensively studied Alaska North Slope crude oil (ANSCO) using two different exposure methods, water-accommodated fractions containing dispersed oil microdroplets and oiled gravel effluent. Overall, both crude oils produced a largely overlapping suite of defects, marked by the well-known effects of PAH exposure on cardiac function. Specific cardiotoxicity phenotypes were nearly identical between the two oils, including impacts on ventricular contractility and looping of the cardiac chambers. However, with increased weathering, tissue-specific patterns of aryl hydrocarbon receptor (AHR) activation in the heart changed, with myocardial AHR activation evident when alkyl-PAHs dominated the mixture. Our findings suggest that mechanisms of cardiotoxicity may shift from a predominantly AHR-independent mode during early weathering to a multiple pathway or synergistic mode with prolonged weathering and increased proportions of dissolved alkyl-PAHs. Despite continued need for comparisons of crude oils from different sources, the results here indicate that the body of knowledge already acquired from studies of ANSCO is directly relevant to understanding the impacts of other crude oil spills on the early life history stages of fish.
