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Optimalizace procesu triploidizace u candáta obecného (Sander lucioperca)
TRNKA, Kamil
This thesis was aimed on optimization of induction of triploidization of pikeperch (Sander lucioperca) using cold, hot and pressure shocks. To induce the triploid status of the larvae using cold shock fertilized eggs of pikeperch were dropped into the cold bath of temperature 0,5-1°C in 2, 4, 8, 12 and 16 minutes post fertilization with shock duration of 20, 40, 60, 90 and 120 minutes. Hot shock was induced by 30°C bath 2, 4, 8, 12 and 16 minutes post fertilization with duration of shock 5, 10, 20, 30 and 40 minutes. Pressure shock was also tested for induction of triploidization using pressure of 70 MPa 5, 10 and 20 minutes post fertilization with duration of shock 5 minutes. Ploidy level was then determineted using flow cytometry. As a result hatchability (%), share of malformed larvae (%), share of triploid individuals (%) and yield of triploids (%) were determined. None of the experiemental shocks have led to a 100% share of triploids concerning the samples examined by flow cytometry. Best result was reached via pressure shock with duration of 20minutes which resulted with share of triploid individuals of 95% and yield of triploids 12.2+-2.5%. It must be noticed that increasing duration of pressure shock resulted in decreased hatchability and increased share of malformed larvae. Second best result was achieved via cold shock. Worst results were obtained via hot shock.
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Induction and potential use of monosex populations of pikeperch (Sander lucioperca) in intensive farming
ŠVEJDA, Pavel
The aim of this study was to induce monosex populations of pikeperch using the method of direct masculinization and direct feminization in order to change sex and evaluate the production parameters and body indices of the treated groups of pikeperch. For direct masculinization, 17 -methyltestosterone was used at a dose of 30 or 50 mg.kg-1 for 30 or 60 days. For direct feminization, 17 -estradiol was used at a dose of 30 mg.kg-1 feed for 30 days. Individuals of pikeperch with TL = 51.52 +- 4.19 mm and W = 1.23 +- 0.26 g, FC = 0.9 +- 0.3 were used for the experiment. In the experiment, direct feminization achieved a sex ratio 98.3 % of females and 1.7 % of males. This is the first record of an almost all-female population induced with 17 -estradiol. The highest level of masculinization of the tested individuals was achieved in the group exposed to 17 -methyltestosterone at a dose of 30 mg.kg-1 feed for 60 days. In this population, 75 % of individuals with male genital tissue were found, of which 21.7 % were individuals whose testicular sperm could be used to produce an all-female population. In groups treated with 17 -methyltestosterone for 60 days, the presence of "neomales" and intersex (hermaphrodite) individuals was observed. The experiment revealed that the use of the hormones 17 -methyltestosterone and 17 -estradiol can temporarily cause growth suppression, particularly during and shortly after exposure of individuals to these hormones. However, it does not have a lethal effect on individuals in the doses we applied. The higher growth rate of pikeperch females was not confirmed in the test. Females treated with 17 -estradiol did not show higher weight gains compared to the control group. A significant difference in the achieved final weight was not observed between both sexes in the control group at the end of the experiment.
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Vliv nasycení kyslíku ve vodě na efektivitu intenzivního chovu candáta obecného (Sander lucioperca) v recirkulačním akvakulturním systému
VOJTA, Petr
This thesis deals with an issue of Zander (Sander lucioperca) production in a recirculating aquaculture system RAS in different oxygen rates (50-80% O-, 80-110% Os and O+ 110-150%). Zander weighted W=22,98?15g was planted into two identical recirculating systems with different water temperature. SGR, FCR and FC of survival and general health condition of kept fish in hematology, biochemistry as well as stress indicators were evaluated. The results proved a negative influence of hypoxia (50-80%) on the food reception, growth and general survival of experimental fish kept in this environment in both the recirculating systems with water temperature 20 and 23°C. In the group O- kept in RAS 20°C, higher coefficient of FCR=1,11 was proved in comparison with group O (normoxia) and group O+ (hyperoxia), where no significant difference (p0,05) was recorded. The health condition showed a significant difference (p0,05) of O group in comparison with group O+ and O in RAS 20°C during the TBARS evaluation (brain, gills, muscle), assessing SOD in liver, and GPx (brain and muscle). By determining the HSI, SSI and VSI indexes, the significant differences (p0,05) of HSI and VSI for O+ and O groups in comparison with O- were proved.
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Inovace chovu larev candáta obecného (Sander lucioperca L.) při použití vířníků druhu Branchionus plicatilis
IMENTAI, Aiman
Pikeperch (Sander lucioperca L.) has been realized as one of the promising candidates. Currently one of the crucial bottlenecks in pikeperch larviculture is larval first feeding when high mortalities occur. Since recognition of rotifers as potential candidate for larvae culture, its value has grown tremendously in fish hatcheries. Although using rotifers and Artemia as a starter food items has become a common practice in hatcheries, yet rotifers has not been used for pikeperch larval culture. Many questions regarding introduction of rotifers during pikeperch larval first exogenous feeding are still not answered. The aim of this Ph.D. thesis was to maximize survival, growth and fitness of pikeperch larvae during first exogenous feeding by using rotifers Brachionus plicatilis. The effects of B. plicatilis on survival rate, growth performance and fitness of pikeperch larvae during first feeding were evaluated in the first study. Larvae were reared under three different diets (Artemia; Art /rot; rotifers) from 3 till 17 days post hatch (DPH). Using rotifers as first diet for pikeperch larvae was shown to benefit survival and growth rates. Larvae fed on rotifers only or combined diet (rot/Art) obtained higher survival and growth compared to Artemia diet. It was found that essential fatty acids of rotifers and their smaller size had a crucial effect on the larval survival and performance. The findings of the first study showed that the mixed diet (rot/Art) could be recommended as innovated first exogenous feeding in pikeperch larvae. The objective of the second study was to optimize the first exogenous feeding regime for pikeperch larvae using rotifers and Artemia. Larvae were fed with rotifers for 3 days and afterwards from 8 to 17 DPH they were adopted to 5 different regimes. It was found that feeding pikeperch with rotifers from 5 to 8 DPH and afterwards exclusively with Artemia or mixed of rotifers and Artemia till 17 DPH can ensure high survival and growth rates, and better development of digestive organs. Feeding larvae with rotifers from 5 to 8 DPH and afterwards replacing with Artemia till 17 DPH is recommended as an optimum feeding regime because larval survival and growth were satisfying, and it reduces the costs for production. The main aim of the third study was to determine the optimal salinity for rearing of pikeperch larvae using B. plicatilis. Rotifers were stocked under different salinities and motility was investigated over a 6-h period. The same salinities were used in second trial of this study to quantify the effect on pikeperch gut fullness over the course of 11 h. In the third trail, the survival and growth rate of larvae from 4 to 11 DPH at low and medium salinities were analyzed. Results of this study showed that rotifers stocked at all tested salinities, except for freshwater retained motility for over a 6-h period. Pikeperch larvae reared at 2? and 4 ? showed higher survival and growth rate during trial compared to freshwater. The results of this study showed that larvae in low salinity water had higher survival and growth rate during initial exogenous feeding with B. plicatilis. The aim of fourth study was to determine the optimal rotifers density for pikeperch larvae at the beginning of exogenous feeding. Larvae were divided into 4 groups at different rotifers densities from 5 to 9 DPH. The best growth performance was achieved at the highest rotifers density, however survival rate did not significantly differ among the groups. The results suggested that B. plicatilis at density of 6 ind/mL can be considered optimal for larval growth from 5 to 9 DPH when balancing production and costs, compared to higher prey densities.
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STUDIUM ZÁKLADNÍCH MECHANISMŮ PERITONEÁLNÍHO ZÁNĚTU U CANDÁTA OBECNÉHO (Sander lucioperca)
CHÁBERA, Jan
Pike-perch (Sander lucioperca) is a species of fish whose breeding in recirculation systems has a great prospect in the years to come. Due to the unfavorable conditions of intensive rearing of these fish in recirculation systems, they are often exposed to stress resulting in reduced fish defenses. Thus, fish are exposed to attack of a wide range of bacteria. Although there are preventive measures to protect fish against pathogen attack, knowledge of the immune system and the immune response of the fish is crucial for further evolution of vaccination. Even though we know the mechanisms of immune response of many fish species,but the knowledge of the pike-perch's immune response is very limited.
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ADAPTACE A INTENZIVNÍ CHOV OKOUNKA PSTRUHOVÉHO (Micropterus salmoides) V POROVNÁNÍ S INTENZIVNÍM CHOVEM CANDÁTA OBECNÉHO (Sander lucioperca)
HANZLÍK, Petr
The object of this thesis is to verify Largemouth bass (Micropterus salmoides) as an alternative species to Pikeperch (Sander lucioperca) for fish farming in RAS (Recirculating Aquaculture Systems). Largemouth bass with its good meat quality is comparable to Pikeperch and with its lower sensitivity to stress related to RAS conditions could expand the number of species used in intensive aquaculture. This experiment was split to two parts. In the first part was documented adaptation of Largemouth fingerlings to RAS conditions and artificial feed. After successful adaptation, the second part was started the main experiment. Only 9-16g form pieces were picked from the fish from the first experiment.) The Fish were divided into four groups: Candát 100%, Okounek pstruhový 100%, Candát mix, Okounek mix in three repetitions to nine tanks with capacity of 600 l. Dimensions of these tanks are 101x100x59,5 cm. Each tank was settled by 700 fish. In mixed groups were 350 of Pikeperch to 350 of Largemouth bass in each tank. Second part of experiment lasted 60 days. During that time different parameters of water quality were monitored. Twice a day oxygen, water temperature and once a day pH, NO2- , NH4- were monitored. Every day feeding dosage and mortality were counted. At the end of the experiment all fish were weighed piece by piece to find out the percentage frequency of each weight category in 1 g step. From each tank after every part of the experiment 33 pc of fish were selected and the biometrics were made. Monitored parameters were TL,SL,W and FC, FCR, SGR were counted. Evaluation of outcome and comparison of researched groups pointed to next findings. Largemouth bass showed a slightly smaller growing ability than Pikeperch in RAS. We have to consider a lower water temperature to the end value 21,5°C in system which was set because of Pikeperch sensitivity to bacterial infection and the optimum water temperature for Largemouth bass to 26°C. The experiment proved a high survival of Largemouth bass in groups Okounek 100% 99,86% survival, Okounek mix 99,81% survival. Pikeperch in groups Candát 100% and Candát mix did not exceed 97% in survival. An interesting finding of this thesis proved a positive influence of Largemouth bass to the growth of pikeperch. The group Candát mix had the best results in all monitored parameters TL,SL,W and FC, FCR, SGR.
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Indukce triploidie u candáta obecného (Sander lucioperca)
RŮŽEK, Martin
The aim of this study was to induce the triploidy in pikeperch (Sander lucioperca) with use of a cold shock. To induce the triploidy, fertilised egg were (spawning temperature 14,5 °C) submerged in a cold bath at the temperature of 2 °C. Time of initiation was 1; 3; 5; 7 and 10 minutes post activation. The exposure time was 20 and 40 minutes. Ploidy level of freshly hatched larvae was assessed with use of the flow cytometry. In both exposure times, the hatching rate was getting lower with later time of initiation (20 minutes exposure, hatching rate: 58,4-13,4 %; 40 minutes exposure, hatching rate: 28- 9,6 %). Number of malformed larvae increased with later time of initiation and longer exposure time (20 minutes exposure, malformed larvae 0-47,2 %; 40 minutes exposure, malformed larvae 0-58,8 %). None of the tested combination of exposure time and time of initiation led to a population containing 100 % triploid larvae. However, percentage of triploid larvae grew up with longer exposure time and later time of initiation. The best cold shock combination with highest yield of triploids were after 20 minutes long treatment initiated 10 minutes post activation (57,1 +- 14,2 %) and after 40 minutes long treatment initiated 10 minutes post activation (61,9 +- 8,2 %). The most important finding of this study is that cold shock treatment leads to triploidy in pikeperch. To obtain 100% triploid larvae, shorter exposure time and different shock temperature might be applied. It may also eliminate low hatching rate and high appearance of malformed larvae.
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Optimalizace intenzivního chovu larev candáta obecného (Sander lucioperca L.)
MORAVA, Jakub
The aim of this master thesis was test, comapre and observe the best density of rotifers (Brachionus plicatilis) for growth and survival of zander (Sander lucioperca) larvae stage in the recirculation aquatic systém (RAS). The secondary experiment tests initial feeding of zander by dint of rotifers and consequently by mix of rotifers and artemia. Main experiment observe effect of different density of rotifers on survive and growth of zander. Other observe parameters such as Fulton´s coeficient, total lenght of fish, weight of fish, etc. Fish was divided into 4 groups with different density of feeding and the control group without feeding. Rotifers has been used in density of 2, 6, 10 and 20 pieces per larva. The best growth in "D" group has been compensate by lower surviving. On the other hand the best ratio of survive has been observe in "C" group, which showed lower growth. The optimal rate of growth and survive has been declared in "B" group, which were feed with dose of 6 pieces rotifers for larva. In the second experiment were observe body changes of zander after initial feeding by rotifers folowed with feeding mix of rotifers and artemia. There were observe successful fulfillment of gas bladder and deformation of fish body and spinal after 40 days of keeping larvae in RAS. In the end of experiment there were also observe defirmations body - for example missing lower jaw, upper jaw or both of them. Spinal deformities occured in the form of scoliosis, lordosis, kyphosis and zig zag distortion. The experiment has shown that unsuccessfully filled gas bladder is closely related to the formation of deformitiy in the zander. Another negative factor that affects the filling of the gas bladder is grease on the surface of the water level, so I recommend installing the grease trap in the fill phase of the gas bladder.
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Vývoj úlovků ryb v údolní nádrži Dalešice na řece Jihlavě
Gregr, Tomáš
The Bachelor thesis focuses on evaluation of caught trend in dam reservoir Dalešice (fishery Jihlava 7-8). The main object aim is to evaluate fish caught by angling in decade 2005 - 2014. Thesis focuses on predatory fish species and their ratio to other species. There is used research from 1991 - 2000 to compare results. This work discuses dam reservoirs and species structure of the fish community, compares each species of fish between them and its suitability for dam reservoirs. Amount of predatory fishes caught by anglers decreases during evaluated ten years, depending on quantity of each predatory fish species. The biggest influence had pike (Esox lucius), pikeperch (Sander luciopeca) and asp (Leuciscus aspius).The ratio between predatory fishes and other fish species depends also on proportion of each fish species to total richness of predatory fish species. In the second half of decade (since 2010) the ratio increases in fa-vour of not predatory (cyprinid) fish species.
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Využití střevličky východní (Pseudorasbora parva) při produkci násadového materiálu candáta obecného (Sander lucioperca)
Kadlec, Lukáš
The subject of the Diploma Thesis was to summarize all the data published either from scientific papers or collected during the experiments, relating to the possibility of using topmouth gudgeon as fish food. The main part is composed of the results and conclusions obtained from the experiments conducted in the model recirculation system, under controlled conditions. The experiments were focused on the feed preferences of the pikeperch (Sander lucioperca), for the given size category of the topmouth gudgeon (Pseudorasbora parva), stimulation of the food intake of the pikeperch in the conditions with different amounts of topmouth gudgeon, and on the intraspecific competition for food in cases with different numbers of the stocked pikeperch. Bigger food preference was confirmed for the topmouth gudgeon, in the size category up to 7 cm (on average 29.8 % of the whole body length), than for the topmouth gudgeon bigger than 8.5 cm (on average 42 % of the whole body length). Results also show higher food intake in-tensity in case of continuous supply of topmouth gudgeon, while the intraspecific stimu-lation of the food intake has not been either proven, or disproved. Data obtained enables us to better understand the nutritional activity of the pikeperch, and can be used in working conditions, with the aim to dose the amount of the topmouth gudgeon as fish food.
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