Effects of accelerated photoperiod regimes on the reproductive cycle of the female rainbow trout: I-seasonal variations of plasma lipids correlated with
vitellogenesis.
The gradual increase in the size of the ovarian cells has been attributed to the deposit of lipid in the ovaries during
vitellogenesis (Revathi, Iyapparaj, Munuswamy, & Krishnan, 2012; Castiglioni, & NegreirosFransozo, 2006; Gregati, Fransozo, Lopez-Greco, & Negreiros-Fransozo, 2010).
Influence of temperature regime on endocrine parameters and
vitellogenesis during experimental maturation of "European eel" (Anguilla anguilla) females.
However, it was very common to see ovaries with oocytes in atresia, both in cortical alveoli or
vitellogenesis stages, with different degrees of incidence, but all such cases corresponded with females with evidence of postspawning (Fig.
The bovine or porcine insulin, compared to endogenous ILPS, show varying effects on
vitellogenesis and ecdysteroids synthesis (Brown et al.
Moreover, Hacini [19] reported that in mid March to the end of this month, the females of this species have basic previtellogenesis oocytes and
vitellogenesis.
The production of pre-vitellogenic oocytes was greater than for oocytes in
vitellogenesis, revealing that the recruitment of vitellogenic oocytes from the pre-vitellogenic standing stock occurs continuously in both species.
The stage-specific and seasonal variation of oocyte size frequency distribution, seasonal variation in the percentage of different oocyte stages in individuals in spawning capable phase, and seasonal variation in the mean diameter of oocytes in the tertiary
vitellogenesis stage in individual in spawning capable phase through spawning season are required (West, 1990; Hunter and Macewicz, 1985c; Murua et al.
In addition the smaller body-mass gain of the females without oviposition most likely suggests that those females stopped
vitellogenesis during the experiment.
Oocytes were abundant in most oysters from all treatments by mid-October, at which time the size and appearance of the germinal vesicle, and the presence of oocytes were clear indications of advanced
vitellogenesis.
The successful captive breeding requires the selection of mature fish showing higher chances to respond positively to induction of final maturation and spawning, comprising the selection of individuals that completed
vitellogenesis and with ovaries in the 'dormant stage'.
Subsequent to
vitellogenesis, the E2 levels decreased significantly (P < 0.
