National Repository of Grey Literature 5 records found  Search took 0.01 seconds. 
Vliv teploty na schopnost oplození a líhnivosti při krátkodobém skladování neoplozených jiker síha peledě (Coregonus peled)
The northern whitefish Coregonus peled (Gmelin, 1788), originally from Russia, was introduced to the Czech Republic in 1970 for its tasty meat and good growth ability. Breeding of this species has been very popular in the past. Currently, thanks to the fish-eating predators, traditional breeding of this species is on decline. The aim of this M. Sc. Thesis was to sumarize the avaible information in the field of peled biology, artificial propagation and also information about effect of temperature on the ability of fertilization and hatching for short-term of unfertilized eggs in other salmonid species. In the practical part, the influence of temperature and length of storage of stripped, unfertilized eggs of peled on fertilization, survival to eyed eggs and hatching were observed. Unfertilized eggs were divided into five bowls and deposited in thermo boxes, which were tempered to 2.5, 5, 7.5, 10 and 12.5 °C. After time intervals of 1, 4, 12, 24, 36, 48, 60 and 72 hours, approximately 100 - 200 eggs were taken from each thermobox, which were fertilized with fresh sperm (collected from several males) and water from the hatchery. The fertilized and purified eggs were moved to the incubators with continuously inflow of fresh water. Dead eggs were removed and recorded. Subsequently, fertilization, eyed eggs and hatching eggs were determined. The resulting values of these parameters were expressed as a percentage of the total number of used eggs. High levels of fertilization and survival to eyed eggs were achieved when stored within 1 day from eggs stripping at all temperatures except the highest temperature of 12.5 ° C. As the interval gradually lengthened, the fertilization and survival parameters also decreased, most notably at 7.5 and 10 ° C. To obtain the largest possible amount of fry in fishing practice, it is recommended to store eggs at 2.5 and 5 ° C, up to 48 hours after ova stripping. At higher temperatures, the effective storage time is reduced to 12 hours. Storing eggs for longer than 48 hours, in practical terms has no meaning. At the same time, it was found that at the above-mentioned optimal temperatures for storing eggs (2.5 and 5 ° C), the best hatching results were obtained when storing stripped eggs for 12 hours. Not only for longer, but also for shorter storage lengths, the values of this parameter were lower.
Hormonal induction of ovulation in whitebarred catfish (Agamyxis pectinifrons)
KNOWLES, Jindřiška
The aims of presented work are reviewing of current knowledge about biology and artifical reproduction, evaluation of dopamine inhibition of LH secretion and identification of optimal hormonal treatment of ovulation in tropical whitebarred catfish. Two trials were conducted in years 2012 and 2013. The experiments differed from each other only in the water temperature 29,5 °C (Experiment No.1) and 26 °C (Experiment No.2). In each experiment, the fish were divided into 4 groups. Group A was injected only with mGnRHa, group B was injected with dopamine inhibitor metoclopramide, group C was injected with mGnRHa plus metoclopramide and group D was injected only with physiological saline (0,9 % NaCl). Ovulation occurred only in the groups injected with the combination of GnRHa and dopamine inhibitor, however in both experiments. In Experiment No.1, the ovulation rate was around 60%, relative fecundity was 331,025 +- 47,508 eggs . kg-1, latency interval was at 10.3 +- 0.6 hours and the fecundity index was determined at 13, 8. In Experiment No. 2 ovulation, the level of ovulation was 50%, relative fecundity was 408,561 +- 34,934 pieces of eggs . kg-1, latency interval was 13.7 +- 0.7 hours and fecundity index was 15.35. The results clearly show a strong inhibition of dopamine on LH secretion and show that the combination of GnRHa with dopamine inhibitor can be successfully used to induce ovulation in whitebarred catfish.
Hormonal induction of artificial stripping of the female European catfish (Silurus glanis)
The optimalization way of hormonal induction ovulation females European catfish Silurus glanis was the aim of experiment with the help of hormonal preparate on the base functional of the analogue GnRH. Fish with females were fish out in the ponds early in june and injected by hormonal preparates CPE, Dagin and Ovopel. Was monitoring latency time in dependency of water temperature, percent of ovulated females, relative weight of ovulated eggs, fertilization eggs and hatching performance.
The Short-Term Storage of Unfertilized Roe of the African Catfish (Clarias gariepinus).
The Short-Term Storage of Unfertilized Roe of the African Catfish (Clarias gariepinus). For my Bachelor's Thesis, I address the issue of preserving and incubating the roe of the African Catfish (Clarias gariepinus). This species can be bred very well at high stock concentrations in recirculation systems. The optimal breeding temperature is 25-28°C. Pellets with a concentration of over 40% protein are used as food. The advantages are very rapid growth and high-quality lean meat with a small amount of bones. This species is bred in the Czech Republic on a very limited basis, the reason for this is a conservative approach of both fish breeders and customers. The intensive breeding of the African Catfish is developed mostly in Holland and Hungary, and it is extensively produced in ponds and in certain African countries such as Egypt, Nigeria, Ghana, etc. Reproduction is usually carried out by artificial smearing using hormone-induced ovulation. The possibility of preserving unfertilized roe is known at certain other species of fish bred in aquaculture systems, as there is an effect of water on the unfertilized roe. There is no information available in literature in this respect concerning the African Catfish. There were two objectives of the experiments I carried out. The first objective was to ascertain the possibility of preserving the roe at various temperatures before insemination. The second objective was to ascertain the influence of the contact duration of the uninseminated roe with water on their ability to fertilize. In both cases, the percentage of fertilized roe and the percentage of hatched larvae from the seeded roe were valuable parameters. The roe originated from an artificial smear using a hormonal stimulation of female fish with the Hungarian product Ovopel. The product contains a synthetic analogue releasing hormone luteinizing hormone and a dopaminergic inhibitor supplement. It is used for the artificial propagation of other species of fish in addition to the African Catfish. The experiments began in June 2010 and continued until March 2011. The experiments were first carried out in Vodňany, then in České Budějovice. The first experiment took place in temperatures ranging from 10-30°C. The unfertilized roe were preserved at these temperatures for periods of 0, ?, ?, 1, 2, 4 and 6 hours. Afterwards the fertilization was done using collected sperm and egg samples incubated at 25°C. For the second experiment which took place at a temperature of 25°C, the samples of freshly smeared roe were seeded into dry dishes, poured with water at time intervals from 0 to 10 minutes (at 30 second intervals), then the previously collected sperm was added. Both experiments were done repeatedly for roe that originated from a total of 8 female fish. In both cases, the seeded pieces were counted for the egg samples in the dishes following washing. Their fertilization was evaluated (%) as well as their hatching (%).
Production of sac-fry of perch by means of hormonally induced semiartificial and/or artificial propagation
Kouřil, J. ; Hamáčková, J. ; Lepič, P. ; Lepičová, A. ; Mareš, J. ; Barth, Tomislav
[D-Ala.sup.6./sup., ProNHEt.sub.9./sub., desGlyNH.sub.2./sub..sup.10./sup.] mGnRH and [D-Tle.sup.6./sup., ProNHEt.sup.9./sup., desGlyNH.sub.2./sub..sup.10./sup.] mGnRH were compared in their abilities to induce the ovulation of perch females after the intramuscular administration.

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