Medaka Üretimi Ve Bakımı Üzerine Makale 1
International Zebrafish/Medaka Course
(IZMC)
https://izmc.ezrc.kit.edu/IZMC_theoreticalpart_EN.pdf
Medaka Üretimi ve Bakımı
5.2 Medaka husbandry and breeding (Daniela Vallone, Felix Loosli) It is possible to maintain medaka for a constant supply of eggs in standard aquarium tanks obtained through a pet shop. Under these conditions, the maximal fish density is 1-2 fish per liter. For optimal conditions a recirculating system should be used, where up to 5 medaka per liter can be kept. Exceeding a density of 5 adult medaka per liter in recirculating systems may cause stress for the fish and will negatively affect growth rate and fecundity. For optimal breeding conditions, one male should be kept with four to six females in 4 to 6 liter tanks. As medaka are social animals, it should be avoided to keep single fish in isolation of long periods (several weeks). A number of companies offer standard and custom designed recirculating systems: Müller & Pfleger, Rockenhausen/Germany; AquaSchwarz, Göttingen/Germany; Techniplast, Buguggiate/Italy; AquaticHabitats, Apopka/USA. Common to these systems is a recirculation of the water combined with the use of biological filters to ensure constant water conditions and enrichment with oxygen (Fig. 19. In addition, recirculating water can be sterilized using UV irradiation bulbs. Tank sizes for medaka can vary between 3-15 liters depending on their use as either husbandry tanks for young fish (3l), as mating tanks (6l) or to keep large numbers for stock maintenance. Standard conditions for medaka systems are: 26o C, pH 6.8-7.2, ammonia and nitrite < 2ppm, nitrate < 50 ppm. Medaka tolerate a wide range of water salinity, 200- 600 µS/cm in the fish tanks is acceptable. Reverse osmosis can be used to obtain good quality water to which then salt (Mineral Salt) is added to provide a salinity of 0.3-0.5%. Alternatively, deionized water can be adjusted with tap water, for example 70% deionized water and 30% tap water. This results in an improved buffering capacity of the water due to the carbonate buffer (depending on the water hardness). If necessary tap water should be charcoal filtered to remove chlorine. In addition, the system water can be enriched by the addition of trace elements (such as MikroSal, 100 mg/l). At the EZRC medaka facility, tap and deionized water are mixed to 300 µS/cm conductivity, then 8 g/1000 l mineral salt and 100 mg/l trace elements are added. This results in water with a pH 7 and 300- 320 µS/cm. It is important that no sudden changes in the water conditions occur. Thus, water changes should not exceed 30% of the total water. It is better to exchange smaller volumes at shorter intervals, such as 10% per week. With stable water conditions, adequate feeding and snails to reduce algal growth and ensure removal of excess food, cleaning of the tank systems (i.e. removal of algal growth from the walls and debris from the tank bottom, cleaning of the biological filters, 20% water exchange) is required every 3-4 weeks. The basic water parameters pH, conductivity, hardness, nitrite and nitrate levels should be checked every week. In most cases, medaka can be kept in a zebrafish facility and vice versa, since the requirements to water quality, light and feeding are very similar. With the parameters described in Table 2, the life span of medaka is about 1 year. Medaka can also be kept under light dark cycle conditions of 10 hours light and 14 hours dark (10L:14D), but under these conditions they will not reproduce and their life span will be prolonged to about 2 years. Fig.16: Medaka facility at EZRC 48 International Zebrafish Medaka Course IZMC Medaka fish facilities generally avoid the usage of tank enrichment such as vegetation or objects. It is recognized by the medaka research community that enrichment poses a large risk for contamination of fish facilities with pathogens (especially vegetation that cannot be sterilized). Furthermore tank enrichment will obstruct cleaning and maintenance of fish tanks and therefore may be a source of extra stress for fish as it will prolong these procedures. Feeding The growth rate depends critically on the fish density in the tanks and also on the food supply. Medaka should be fed several times a day with an amount of food that they will eat within 5-10 minutes. Feeding in excess will affect the water quality and result in excessive growth of snails. A combination of live (brine shrimp) and dry food Tab.2: Medaka husbandry conditions 49 International Zebrafish Medaka Course IZMC (for example Tetra-min flakes) is optimal. We feed flakes in the morning and evening and feed with shrimps around noon. Shrimps can also be fed to hatchlings starting two weeks after hatching. Feeding medaka with live brine shrimp larvae is considered a tank enrichment as it will stimulate natural feeding and prey capture behavior. Medaka mating, egg collection: One male together with 1 to 4 females are placed in a suitable tank (~6 l.) under recirculating water conditions. This can either be done the day before or on the same day as egg collection. When fertilized eggs of a specific stage are required, such as for icroinjection at the 1-2 cell stage, it is best to place the male and female fish together during the first three hours of the light period (e.g. 8-11 am when the daily light period extends from 8 am to 10 am). Medaka will mate around the onset of the light period, or within about 15-30 minutes after having been placed together. Females carry the fertilized eggs on their body for several hours. Therefore, the females have to be caught from the tank with a small net and a metal hook (rust-free steel) is used to carefully scrape off the eggs. It is important that the female is placed back into the water as soon as possible, latest after 3-5 minutes to prevent unnecessary stress or even suffocation. The eggs stick together due to hairs on the chorion, thus forming a clump. Move the hook under the belly of the female from head to tail to avoid hurting the gills, scoop out the clump of eggs and then transfer them into a dish with embryo raising medium (ERM) (max. 30 eggs in 6cm dish or 100 eggs in 9 cm dish). Freshly fertilized eggs are initially opaque (milky) but clear within a few minutes. The chorion hardens concomitantly and so freshly fertilized eggs are initially very soft. Clumps of eggs have to be dissociated (to ensure equal oxygen supply) by gently rolling the clump with a finger in the dish. This will rupture the hairs and dissociate the clump. Rolling eggs on a wet filter paper is more suitable for injecting embryos as more hairs are removed by this approach. Remove unfertilized (opaque) eggs and incubate the dish in a suitable incubator (standard: 28o C, 14/10 illumination). Medaka hatch after 7-8 days under these conditions. They reach fertility after 8-12 weeks depending on the strain and density/feeding regime.939495969798 93 Iwahashi H1, Kishi K, Kitagawa E, Suzuki K, Hayashi Y., Evaluation of the physiology of M
https://izmc.ezrc.kit.edu/IZMC_theoreticalpart_EN.pdf
Medaka Üretimi ve Bakımı
5.2 Medaka husbandry and breeding (Daniela Vallone, Felix Loosli) It is possible to maintain medaka for a constant supply of eggs in standard aquarium tanks obtained through a pet shop. Under these conditions, the maximal fish density is 1-2 fish per liter. For optimal conditions a recirculating system should be used, where up to 5 medaka per liter can be kept. Exceeding a density of 5 adult medaka per liter in recirculating systems may cause stress for the fish and will negatively affect growth rate and fecundity. For optimal breeding conditions, one male should be kept with four to six females in 4 to 6 liter tanks. As medaka are social animals, it should be avoided to keep single fish in isolation of long periods (several weeks). A number of companies offer standard and custom designed recirculating systems: Müller & Pfleger, Rockenhausen/Germany; AquaSchwarz, Göttingen/Germany; Techniplast, Buguggiate/Italy; AquaticHabitats, Apopka/USA. Common to these systems is a recirculation of the water combined with the use of biological filters to ensure constant water conditions and enrichment with oxygen (Fig. 19. In addition, recirculating water can be sterilized using UV irradiation bulbs. Tank sizes for medaka can vary between 3-15 liters depending on their use as either husbandry tanks for young fish (3l), as mating tanks (6l) or to keep large numbers for stock maintenance. Standard conditions for medaka systems are: 26o C, pH 6.8-7.2, ammonia and nitrite < 2ppm, nitrate < 50 ppm. Medaka tolerate a wide range of water salinity, 200- 600 µS/cm in the fish tanks is acceptable. Reverse osmosis can be used to obtain good quality water to which then salt (Mineral Salt) is added to provide a salinity of 0.3-0.5%. Alternatively, deionized water can be adjusted with tap water, for example 70% deionized water and 30% tap water. This results in an improved buffering capacity of the water due to the carbonate buffer (depending on the water hardness). If necessary tap water should be charcoal filtered to remove chlorine. In addition, the system water can be enriched by the addition of trace elements (such as MikroSal, 100 mg/l). At the EZRC medaka facility, tap and deionized water are mixed to 300 µS/cm conductivity, then 8 g/1000 l mineral salt and 100 mg/l trace elements are added. This results in water with a pH 7 and 300- 320 µS/cm. It is important that no sudden changes in the water conditions occur. Thus, water changes should not exceed 30% of the total water. It is better to exchange smaller volumes at shorter intervals, such as 10% per week. With stable water conditions, adequate feeding and snails to reduce algal growth and ensure removal of excess food, cleaning of the tank systems (i.e. removal of algal growth from the walls and debris from the tank bottom, cleaning of the biological filters, 20% water exchange) is required every 3-4 weeks. The basic water parameters pH, conductivity, hardness, nitrite and nitrate levels should be checked every week. In most cases, medaka can be kept in a zebrafish facility and vice versa, since the requirements to water quality, light and feeding are very similar. With the parameters described in Table 2, the life span of medaka is about 1 year. Medaka can also be kept under light dark cycle conditions of 10 hours light and 14 hours dark (10L:14D), but under these conditions they will not reproduce and their life span will be prolonged to about 2 years. Fig.16: Medaka facility at EZRC 48 International Zebrafish Medaka Course IZMC Medaka fish facilities generally avoid the usage of tank enrichment such as vegetation or objects. It is recognized by the medaka research community that enrichment poses a large risk for contamination of fish facilities with pathogens (especially vegetation that cannot be sterilized). Furthermore tank enrichment will obstruct cleaning and maintenance of fish tanks and therefore may be a source of extra stress for fish as it will prolong these procedures. Feeding The growth rate depends critically on the fish density in the tanks and also on the food supply. Medaka should be fed several times a day with an amount of food that they will eat within 5-10 minutes. Feeding in excess will affect the water quality and result in excessive growth of snails. A combination of live (brine shrimp) and dry food Tab.2: Medaka husbandry conditions 49 International Zebrafish Medaka Course IZMC (for example Tetra-min flakes) is optimal. We feed flakes in the morning and evening and feed with shrimps around noon. Shrimps can also be fed to hatchlings starting two weeks after hatching. Feeding medaka with live brine shrimp larvae is considered a tank enrichment as it will stimulate natural feeding and prey capture behavior. Medaka mating, egg collection: One male together with 1 to 4 females are placed in a suitable tank (~6 l.) under recirculating water conditions. This can either be done the day before or on the same day as egg collection. When fertilized eggs of a specific stage are required, such as for icroinjection at the 1-2 cell stage, it is best to place the male and female fish together during the first three hours of the light period (e.g. 8-11 am when the daily light period extends from 8 am to 10 am). Medaka will mate around the onset of the light period, or within about 15-30 minutes after having been placed together. Females carry the fertilized eggs on their body for several hours. Therefore, the females have to be caught from the tank with a small net and a metal hook (rust-free steel) is used to carefully scrape off the eggs. It is important that the female is placed back into the water as soon as possible, latest after 3-5 minutes to prevent unnecessary stress or even suffocation. The eggs stick together due to hairs on the chorion, thus forming a clump. Move the hook under the belly of the female from head to tail to avoid hurting the gills, scoop out the clump of eggs and then transfer them into a dish with embryo raising medium (ERM) (max. 30 eggs in 6cm dish or 100 eggs in 9 cm dish). Freshly fertilized eggs are initially opaque (milky) but clear within a few minutes. The chorion hardens concomitantly and so freshly fertilized eggs are initially very soft. Clumps of eggs have to be dissociated (to ensure equal oxygen supply) by gently rolling the clump with a finger in the dish. This will rupture the hairs and dissociate the clump. Rolling eggs on a wet filter paper is more suitable for injecting embryos as more hairs are removed by this approach. Remove unfertilized (opaque) eggs and incubate the dish in a suitable incubator (standard: 28o C, 14/10 illumination). Medaka hatch after 7-8 days under these conditions. They reach fertility after 8-12 weeks depending on the strain and density/feeding regime.939495969798 93 Iwahashi H1, Kishi K, Kitagawa E, Suzuki K, Hayashi Y., Evaluation of the physiology of M
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