Krystyna Demska-Zakeś

University of Warmia and Mazury in Olsztyn, Allenstein, Warmian-Masurian Voivodeship, Poland

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Publications (3)2.41 Total impact

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    ABSTRACT: Rainbow trout homogametic males, (XX or YY sex genotype), can be obtained, respectively, through masculinisation of genetic females or induced androgenesis. Aim of this study was to compare reproductive potential of neo-males (XX) and super-males (YY) with heterogametic males (XY). We measured spermatozoa motility parameters, sperm concentration, osmolality and characterized protein profiles in samples of stripped and testicular sperm obtained from XY and YY males, and testicular sperm of XX males. The motile spermatozoa, as measured by both subjective method and CASA, showed no differences between testicular sperm of XX males and stripped sperm of XY and YY males whereas testicular sperm of XY and YY males had significantly lower sperm motility. Result of protein densitometry showed similarities in protein profile between seminal plasma of XY and YY males and testicular fluids of XX males. Testis of XX males showed specific histological structures of cysts consists hypertrophied Sertoli cells.
    No preview · Article · May 2011
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    ABSTRACT: Many industrial and agricultural chemicals (including heavy metals and alkylphenols) present in the environment have adverse effects on the reproductive function in fish. Three studies were conducted to assess toxicity of these chemicals towards reproduction of freshwater fish. It was shown that heavy metals added to the diets accumulate in brain tissue of carp, and this accumulation results in inhibition of the secretion of noradrenaline and stimulation of the secretion of dopamine in the hypothalamus. These processes results in a disturbance of hormonal equilibrium of the hypothalamo-pituitary system, which can unfavorably influence the efficiency of artificial spawning in fish. Quality of salmonid and sturgeon sperm was impaired after in vitro exposure to heavy metals. The degree of this toxic effect was species-specific. It was demonstrated that sperm motility parameters appeared to be good indicators of adverse effects of heavy metals fish sperm. The protection role of seminal plasma against toxic effects of heavy metals was suggested for salmonid fish. Oral application of 4-nonylphenol (NP) disrupted reproduction in pikeperch. In juvenile fish a decrease in the percentage of males and an increase of intersex fish was observed in relation to dose of NP and time of exposure to this alkylphenol. Exposure of adult males to the NP led to the reduction in fecundity, milt quality and fertility.
    Full-text · Article · Feb 2006 · Reproductive biology
  • Piotr Hliwa · Krystyna Demska-Zakeś · Andrzej Martyniak · Jarosław Król
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    ABSTRACT: The objective of the studies was to analyse the process of oogenesis in vimba from a non-migratory population living in the waters of Drawieński National Park in north-west Poland. The character of spawning of this species is an obstacle in determining the right moment to catch spawners or developing artificial spawning biotechniques. Previtellogenesis of vimba begins about six months after hatching and lasts three years. The trophoplasmatic growth of oocytes (October-March/April) begins when carbohydrate vesicles appear near the nuclei oocytes of sexually mature females (aged 4+). Just before spawning, granulated, lipoprotein-like substances are cumulated. The resorption of pre-ovulation corpora lutea (non-ejected oocytes) and post-ovulation corpora lutea (ruptured theca folds and follicles) begins in the ovary of vimba in the middle of June. These were observed in histological cross sections for about two to three months. Describing the process of oogenesis can provide a foundation for developing practical applications in aquaculture aimed at preserving the biodiversity of the park's waters and this critically endangered species of the Polish ichthyofauna.
    No preview · Article · Feb 2003 · Folia Biologica