|
|
Isolation of early stages of germ cells in pikeperch (\kur{Sander lucioperca})
GÜNGÖR, Ege
A practical technique for enzymatic dissociation and isolation of pikeperch (Sander lucioperca) (Percidae, Teleostei) early stage germ cells (eGC), including spermatogonia and spermatocytes, is reported in this study. Their potential to differentiate into functional gametes, and transmit genetic information to the next generations makes them suitable for cryopreservation and surrogate reproduction studies by germline chimera. Two different age groups (14 month old and 18 month old) of pikeperch were used to adjust the correct stage of eGC isolation. Finally the 18 month old samples were selected due to their high average gonadal volume (0.513 g). 10 ml PBS + 0.3% trypsin (304 mOsm/kg, pH 8) were used for enzymatic dissociation of testicular cells and they were sorted by centrifugation in Percoll density gradient. eGCs were identified on the basis of their ploidy level by CYSTAIN DNA 1 steps kit (PARTEC) and morphological characteristics trough by light microscopy. Cell counting was performed on histological sections and Percoll gradient layers whit the method of random square counting. The method of isolation enriched the number of eGC from 41.3% to 84.7%, obtained from the 33% of Percoll concentration.
|
|
| |
|
|
Adaptation of Intensively Bred Juvenile Fish of Pikeperch (\kur{Sander lucioperca}) to a Pond Condition
CHOTĚBORSKÝ, Michal
The aim of this study was to evaluate the adaptability of juvenile fish of pikeperch (Sander lucioperca) artificially bred in the recirculation system, which were planted to experimental ponds. Within this study of adaptability, the survival rate of planted fish and their growth in determined period was observed. Later, after several months of breeding the pikeperch in experimental ponds, the returnable adaptability was evaluated, when the fish from ponds were returned to the recirculation system, where they were adapted back to the controlled breeding conditions and artificial feed. Again, the survival rate and growth of adapted fish was evaluated.
|
|
|
Optimization of harvest of juveniles of pikeperch (\kur{Sander lucioperca}) taken out of ponds and following ability of the fish to adapt to system RAS
HAMPL, Jan
Within my bachelor thesis I have been trying to resolve the possibilities of optimization of harvest of juveniles of pikeperch (Sander lucioperca) taken out of ponds, and continuously I have been tracking the ability of the fish to adapt to system RAS that is applied at the experimental fish culture facilities at FROV JU. Working at the fish harvest it has shown me to be important to synchronize the work of every one of the assistants during the individual activities. The fish have been harvested in a very short time and carefully taken to already prepared transport boxes. We checked the most important parameters for the quality of water, its temperature and oxygen saturation. The mortality of the fish during the harvest and transport did not get over 2 %. Just after the transport to experimental fish culture facilities at FROV JU, to the system RAS at Vodnany, the harvested fish has been placed to 9 tanks for the weaning period. Each out of three ponds always received three tanks of harvested and adapted fish. The experiment at RAS has been divided into three parts. First part has been about the weaning period of the fish to the RAS system and the artificial food. The results were very satisfying. I have been following these parameters: SGR, FCR, increase of biomass, survival and cannibalism at the tanks. The level of survival from the pond Rohlíček has been around 83,6 %, the pond Bejkovna 69,7 % and Horažďovice 4 the level of survival was 71,8 %. After finalizing the weaning period we did biometry for 37 of selected representatives. Second part has been the 1st post-weaning period. Here I focused at the parameters such as SGR, FCR, increase of biomass, survival and cannibalism at the tanks. The level of survival from the pond Rohlíček has been around 84,17 %, the pond Bejkovna 83,83 % and Horažďovice 4 the level of survival was 82,83 %. After finalizing the 1st post-weaning period we did biometry for 37 of selected representatives. Third part has been the 2nd post-weaning period. Here I focused at the same parameters as above such as SGR, FCR, increase of biomass, survival and cannibalism at the tanks. The level of survival from the pond Rohlíček has been around 87,5 %, the pond Bejkovna 88,17 % and Horažďovice 4 the level of survival was 87,17 %. After finalizing the 2nd post-weaning period we did biometry for 37 of selected representatives, the experiment was evaluated and pikeperch juveniles were sold to the French company Asialor.
|
|
| |
|
| |
|
| |
|
| |
|
| |
|
|
Intensive Pikeperch Fry Feeding (Stizostedion lucioperca)
SVĚTNIČKA, Michal
Tato studie je zaměřena na možnosti využití candáta obecného (Stizostedion lucioperca) pro intenzivní chov ryb v umělých podmínkách. Největším úskalím v počáteční fázi odchovu je bezesporu naplňování plynového měchýře, proto byl k pokusu použit rozkrmený plůdek z přirozeného rybničního chovu rybářství Hluboká. Důležitým bodem intenzivního odchovu je přechod candáta z přirozené potravy na uměle sestavenou krmnou dietu. Byly provedeny dva laboratorní experimenty s převodem rychleného plůdku při využití kombinované stravy (suchá dieta se živou složkou) a vlhčené stravy, při nichž se sledovalo procento přežití a specifická rychlost růstu SGR, dále i krmný koeficient. V prvním pokusu v délce trvání 30 dní, byly použity ryby o počáteční průměrné délce 31,0{$\pm$}0,97 mm a průměrné hmotnosti 0,201 g. Na začátku druhého pokusu v délce trvání 16 dní, měly ryby počáteční průměrnou velikost 33,1{$\pm$}1,11 mm o průměrné hmotnosti 0,246 g. Po skončení obou pokusů byla vyhodnocena úspěšnost převodu. Varianta s kombinovanou stravou, dosáhla úrovně přežití 40,4 %, o průměrné velikosti 3,69 cm, průměrné hmotnosti 0,314 g a SGR byla 1,55.d־{$^1$}, navíc byla část ryb navyklá pouze na příjem zooplanktonu a nepřijímala suchou dietu.U varianty s využitím polovlhkého krmiva bylo dosaženo přežití na úrovni 45,24 %, průměrné velikosti 4,17cm, průměrné hmotnosti 0,560 g, SGR byla 5,12 %.d־{$^1$} a krmný koeficient činil 4,1. Na základě dosažených výsledků lze pro užití v rybářském provozu doporučit metodu přímého převodu s využitím polovlhkých granulí. Z těchto získaných výsledků a ze závěrů výzkumných studií dalších autorů vyplývá, že candát obecný je vhodným druhem pro intenzivní akvakulturní chov.
|
guest ::
