Foto del docente

Albamaria Parmeggiani

Associate Professor

Department of Veterinary Medical Sciences

Academic discipline: VET/02 Veterinary Physiology


Keywords: metabolic hormone gonadal maturity nutrition and reproduction endocrine disruptors intestinal ontogenesis and larval weaning

1 Influence of enviromental factor on sexual activity of male and female teleost fish

2 Influence of endocrine disruptors on sexual activity of mature male and female teleost fish

3 Reproductive and metabolic endocrinology applied to Veterinary Science

4 Study of intestinal ontogenesis and larval weaning

1 Effect of environmental factors on gonad maturation processes of Teleosts

The photoperiodic techniques (defined as artificial manipulation of the photoperiod) are used in large scale by farmers in order to induce spawning in the broodstock. All this is made necessary both by the strong seasonal reproductive that characterizes most aquaculture species, and their difficult acclimatization in captivity. In spite of these measures, it is particularly difficult to predict the period of spawning within the broodstock. Because some freshwater species, and in particular the Ciprinus carpio and its homeomorphic varieties, do not exhibit sexual dimorphism, the evaluation of specific parameters, such as the vitellogenin assay (VTG, marker of the female sex) could allow to separate the sexes optimizing the sex ratio in the breeding tanks.

Particularly interesting, is also the role played by thyroid hormones that are of great importance in the cold-blooded organisms, as they control physiological processes such as larval development, growth, utilization of nutrients and reproductive processes.

The research aims to monitor the seasonal variations of steroidogenetic gonadal, thyroid hormones (T3 and T4), cortisol and vitellogenin (VTG).

2 Evaluation of the effects of ECDs (endocrine disruptors) of the endocrine Teleosts.

Many studies have shown that anthropogenic factors, such as pollutants, may alter the endocrine functions, interfering with the cascade of events that lead to the attainment of sexual maturity and gamete deposition. The gonads of teleosts produce sex steroids: 17-beta-estradiol in the female, testosterone and 11-ketotestosterone in males. The production of oestradiol by the liver follicular cells involves the release of vitellogenin (VTG), a glicolipophosphoprotein that will be accumulated as a reserve substance in the cytoplasm of the egg cell. The perfluorinated organic compounds (PFOS) have wide application as a starting material for polymers, surfactants and pesticides resulting in a wide global distribution. For their hydrophilic nature, they do not accumulate in the lipids, but are found in high concentrations in the blood and in the liver. They have the chance to interact with plasma proteins, including sexual hormone-binding and corticoid binding globulins and presenting the hypothesis that this would lead to an alteration of the normal endocrine function. Because of their chemical nature PFOS can potentially bind to sites that are normally occupied by steroid and thyroid hormones resulting in an endocrine disrupting action. Based on the research carried out on freshwater fish, PFOS are able to determine morpho-functional alterations on the hypothalamic-pituitary-gonadal axis. The research aims to develop an experimental model of endocrine disruption by Perfluorooctanesulfonic acid (PFOS) in crucian carp stocked under controlled conditions with the aim to evaluate changes in the endocrine profile for 17-beta-estradiol, testosterone, cortisol, T3 and T4 and vitellogenin in samples at short (within 1 month) and long (4, 6 and 9 months) exposure

3 Control of energy homeostasis and reproductive activity in the major livestock species

To understand the mechanisms that underlie the influence of nutrition on reproduction it is necessary to expand the current knowledge on the metabolic and endocrine reproductive structure of animals at different times, particularly in those characterized by special energy demands. The identification of these signals represents a fundamental acquisition in order to study the appropriate dietary regimes to support an efficient reproductive function and accurately identify the range of metabolic conditions in which it is necessary to stock the animals. Specific surveys conducted in the past have shown clear and obvious relationships between restriction in nutrient and a decreased pulsatile secretion of gonadotropins, a delay in the onset of puberty, a cyclic or delayed ovarian activity in the postpartum, a decreased number of ovulatory follicles, lower oocyte fecundability.Beyond the best-known endocrine factors, the influence of hormones and neurohormones should be taken into account such as leptin, ghrelin, the axis (GH, IGF-1), due to the recent discovery of their involvement in the control of the animal appetite, satiety and metabolism. Control of the reproductive activity of the male eel through the vatulation of sperm motility with the use of activation / storage medium

4 Study of intestinal ontogenesis and larval weaning

These researches are aimed at understanding the physiological changes that occur in the digestive system in Anguilla anguilla and Acipenser Naccarii larvae during the resorption of the yolk sac and the initiation of exogenous feeding.




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