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.
