Lighting conditions during incubation can influence embryonic development, post-hatching ontogeny... more Lighting conditions during incubation can influence embryonic development, post-hatching ontogeny and production efficiency. Previous studies revealed that different light colours differently affect pineal melatonin biosynthesis in embryos and postembryonic development of broiler chickens, but physiological mechanisms mediating these effects are not known. Cold and warm white light consists of different wavelengths and therefore the aim of the present study was to explore if these two lights can differently influence the development of circadian melatonin biosynthesis, production of thyroid hormones and corticosterone, concentration of metabolites (glucose, cholesterol and triacylglycerols) as well as expression of two important immune genes, presenilin 1 and avian beta-defensin 1 (AvBD-1). We evaluated these traits in embryos before hatching (456, 460, 465, 468 and 472 h of incubation) and in hatchlings. The rhythmic profile of pineal melatonin with higher concentrations during the...
Sex steroid levels increase during sexual maturation and cause alterations in many physiological ... more Sex steroid levels increase during sexual maturation and cause alterations in many physiological and morphological traits. Some of these changes may be connected with age-dependent and intersexual differences in the immune system. This topic is still insufficiently understood, especially in avian species, partially due to methodological limitations. In this study we measured the gene expression of proinflammatory cytokines (IL-1β, IL-6, IL-18) and chemokines [K60 (IL-8-like chicken chemokine — CXCLi1), CAF (IL-8-like chicken chemokine — CXCLi2), and K203] in mononuclear cells isolated from blood and spleen after in vitro stimulation with lipopolysaccharide (LPS). Samples were collected from chickens at two ages (from pullets before sexual maturity and from sexually mature egglaying hens). After LPS stimulation, a substantial increase was recorded in the gene expression of IL-6 and K203. All other measured genes were expressed at low levels in mononuclear cells irrespective of cell s...
Comparative biochemistry and physiology. Part A, Molecular & integrative physiology, 2014
Yolk testosterone concentrations vary in response to environmental conditions and different testo... more Yolk testosterone concentrations vary in response to environmental conditions and different testosterone contents can subsequently modify the phenotypic traits of offspring. Apart from effects on growth, proactive behaviour and secondary sexual characteristics, the possible negative impacts of maternal testosterone on the immune system are often considered a limitation for its deposition. The effects of maternal testosterone can be modulated by postnatal environmental conditions, such as the availability of food resources. However, the majority of studies considering the effects of maternal testosterone on the immune system have been conducted under optimum conditions. We evaluated the influence of genetic selection for high (HET) and low (LET) egg testosterone content in Japanese quail on immune responsiveness of offspring to phytohaemagglutinin (PHA) and lipopolysaccharide (LPS) stimulation under severe protein restriction. Protein restriction negatively influenced body weight and...
ABSTRACT A broad variability of yolk androgen levels is considered as an important source of adap... more ABSTRACT A broad variability of yolk androgen levels is considered as an important source of adaptive phenotypic plasticity. This variability of maternal androgen deposition is explained by environmental variation and also by genetic differences among avian mothers. We experimentally investigated such heritable variation of testosterone (T) levels in the egg through the bidirectional selection of Japanese quail. The response to selection for yolk T concentrations was evaluated in downward (low egg T, LET) and upward (high egg T, HET) directions over five generations. Moreover, the correlative response of circulating sex steroids to selection was examined by a comparison of plasma T and estradiol levels between the HET and LET females. We observed a distinct pattern of the response to selection in the HET and LET lines with the stronger response occurring in the upward direction and a limited potential for selection in the downward direction. In the HET line, the population mean increased more than double as compared to the initial population but it seems to be still below its plateau. The LET line reached the selection limit in the second generation suggesting that yolk T concentrations were close to their physiological minimum. Estradiol levels were higher in the circulation of the HET than LET females without changes in plasma T concentrations underlying specific control mechanisms for yolk and plasma hormone levels.
Lighting conditions during incubation can influence embryonic development, post-hatching ontogeny... more Lighting conditions during incubation can influence embryonic development, post-hatching ontogeny and production efficiency. Previous studies revealed that different light colours differently affect pineal melatonin biosynthesis in embryos and postembryonic development of broiler chickens, but physiological mechanisms mediating these effects are not known. Cold and warm white light consists of different wavelengths and therefore the aim of the present study was to explore if these two lights can differently influence the development of circadian melatonin biosynthesis, production of thyroid hormones and corticosterone, concentration of metabolites (glucose, cholesterol and triacylglycerols) as well as expression of two important immune genes, presenilin 1 and avian beta-defensin 1 (AvBD-1). We evaluated these traits in embryos before hatching (456, 460, 465, 468 and 472 h of incubation) and in hatchlings. The rhythmic profile of pineal melatonin with higher concentrations during the...
Sex steroid levels increase during sexual maturation and cause alterations in many physiological ... more Sex steroid levels increase during sexual maturation and cause alterations in many physiological and morphological traits. Some of these changes may be connected with age-dependent and intersexual differences in the immune system. This topic is still insufficiently understood, especially in avian species, partially due to methodological limitations. In this study we measured the gene expression of proinflammatory cytokines (IL-1β, IL-6, IL-18) and chemokines [K60 (IL-8-like chicken chemokine — CXCLi1), CAF (IL-8-like chicken chemokine — CXCLi2), and K203] in mononuclear cells isolated from blood and spleen after in vitro stimulation with lipopolysaccharide (LPS). Samples were collected from chickens at two ages (from pullets before sexual maturity and from sexually mature egglaying hens). After LPS stimulation, a substantial increase was recorded in the gene expression of IL-6 and K203. All other measured genes were expressed at low levels in mononuclear cells irrespective of cell s...
Comparative biochemistry and physiology. Part A, Molecular & integrative physiology, 2014
Yolk testosterone concentrations vary in response to environmental conditions and different testo... more Yolk testosterone concentrations vary in response to environmental conditions and different testosterone contents can subsequently modify the phenotypic traits of offspring. Apart from effects on growth, proactive behaviour and secondary sexual characteristics, the possible negative impacts of maternal testosterone on the immune system are often considered a limitation for its deposition. The effects of maternal testosterone can be modulated by postnatal environmental conditions, such as the availability of food resources. However, the majority of studies considering the effects of maternal testosterone on the immune system have been conducted under optimum conditions. We evaluated the influence of genetic selection for high (HET) and low (LET) egg testosterone content in Japanese quail on immune responsiveness of offspring to phytohaemagglutinin (PHA) and lipopolysaccharide (LPS) stimulation under severe protein restriction. Protein restriction negatively influenced body weight and...
ABSTRACT A broad variability of yolk androgen levels is considered as an important source of adap... more ABSTRACT A broad variability of yolk androgen levels is considered as an important source of adaptive phenotypic plasticity. This variability of maternal androgen deposition is explained by environmental variation and also by genetic differences among avian mothers. We experimentally investigated such heritable variation of testosterone (T) levels in the egg through the bidirectional selection of Japanese quail. The response to selection for yolk T concentrations was evaluated in downward (low egg T, LET) and upward (high egg T, HET) directions over five generations. Moreover, the correlative response of circulating sex steroids to selection was examined by a comparison of plasma T and estradiol levels between the HET and LET females. We observed a distinct pattern of the response to selection in the HET and LET lines with the stronger response occurring in the upward direction and a limited potential for selection in the downward direction. In the HET line, the population mean increased more than double as compared to the initial population but it seems to be still below its plateau. The LET line reached the selection limit in the second generation suggesting that yolk T concentrations were close to their physiological minimum. Estradiol levels were higher in the circulation of the HET than LET females without changes in plasma T concentrations underlying specific control mechanisms for yolk and plasma hormone levels.
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Papers by Zuzana Kankova