Elizabeth Romagosa

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Fecundity and oocyte development in Salminus hilarii female brood stock were analyzed with the aim of investigating the impact of migration impediment on oogenesis. Histological analyses of the ovaries were performed in adult females caught in two different environments—the Tietê River (natural) and captivity—and the gonadossomatic index, oocyte diameter(More)
The efficiency of Ovaprim™ salmon gonadotropin-releasing hormone agonist (GnRHa) and dopamine antagonist on the induction of spawning and spermiation in Prochilodus lineatus in comparison with the commonly used method using pituitary extract (PE) was evaluated. Females received PE at 0.5 + 5.0 mg/kg and Ovaprim™ at 0.05 + 0.45 ml/kg or at 0.125 + 0.375(More)
The aims of the present study were to analyze the gonadal structure of Pseudoplatystoma fasciatum males during their annual cycle to enhance understanding of their reproductive biology and to improve the hormonally induced reproduction and culture of this species in hatcheries. We adopted the recently proposed method that establishes reproductive classes(More)
We identified adhesive junctions and gap junctions between Sertoli cells, between Sertoli and germ cells and between germ cells in the testis of P. fasciatum, a catfish of commercial relevance. To investigate the role of these junctions in spermatogenesis, as well as the molecular composition of the junctions, we performed an immunohistochemistry light(More)
The objective of this study was to assess the growth performance and the histomorphometric characterization of the middle intestine of GIFT strain Nile tilapia, Oreochromis niloticus juveniles fed probiotics, added either before or after the feed processing. The experimental design was completely randomized, with five treatments and five replications:(More)
The processes of ovarian regression and follicular atresia which reproduction was not induced by hormone in confined cachara, Pseudoplatystoma fasciatum, were investigated. The macro and microscopic characteristics (oocytes diameter and histology) of the ovaries were described every 20 days, in four stages: initial regression (Rg I = first 20 days),(More)
The objective of this study was to assess the influence of temperature and time on the storage of fresh Steindachneridion parahybae oocytes. Two experiments were carried out: (1) the fertilization rates of oocytes exposed to temperatures of 5, 15, 28 (room temperature) and 35°C were assessed 15min (control), 115, 235 and 355min after release; (2) the(More)
This study describes at ultrastructural level the germ cells in the testis of matrinxã (Brycon cephalus) raised in captivity. The specimens 'matrinxã' were maintained in four breeding tanks of 200 m(2), at the Aquaculture Research Center at Vale do Ribeira-CEPAR, from Fishery Institute, in Pariquera-Açu City, São Paulo, Brazil. The samples were collected(More)
The objective of this research was to verify the effects of cooling embryos of pacu, Piaractus mesopotamicus, in four stages of development during two stocking periods. The stages of embryo development were at: blastoderm, ∼ 64 cells-1.4 h after fertilization (haf); 25% of the epiboly movement--5.2 haf; blastoporous closing--8.0 haf; and optical vesicle(More)
The present study investigates the effect of different slow chilling curves on the storage of pacu (Piaractus mesopotamicus) embryos submitted to chilling at -8°C. Embryos at the blastopore closure stage were divided into two groups: G1 - embryos exposed to cryoprotectant solution containing methanol (10%) and sucrose (0.5 M), treated as follows: (T1) taken(More)