Occurrence and significance of ovarian and follicular regression in cachara Pseudoplatystoma fasciatum (Linnaeus, 1766): a histology approach

Abstract

Occurrence and significance of ovarian and follicular regression in cacharaPseudoplatystoma fasciatum (Linnaeus, 1766): a histology approach ABSTRACTThe 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), intermediate regression (Rg II = from 21st to 40th day), final regression (Rg III = from 41st to 80th day) and the recovering stage, called resting II (R II = from 81st to 150th day). The experiment was conducted from late January (summer -longer days) to May (autumn -shorter days). In the beginning, A0 samples showed oocyte diameters ranging from 437.5 to 1,187.5µm, suggesting that oocytes were in perinucleolar, at final maturation and atretic phases. After 150 days, the diameters reached the lowest values and a ruptured zona radiata, as well as the nearly complete reabsorption of the yolk could be visualized. At the same time, a sharp decrease in the mean values of the gonadosomatic index (GSI), water temperature, photophase and rainfall was observed. The gradual involution of this long process was dynamic and complex, affecting the spawning success (fertilization, eclosion and larvae survival rates) and, consequently, the whole productive system. Keywords: cachara, Pseudoplatystoma fasciatum, ovarian regression, atretic follicle, histology RESUMO Estudaram-se os processos de regressão ovariana e atresia folicular em cachara, Pseudoplatystoma fasciatum, mantida em cativeiro, na reprodução não induzida por hormônios. As características macro e microscópicas (diâmetro dos ovócitos e histologia) dos ovários foram descritas a cada 20 dias, em quatro estádios: na regressão inicial (Rg I -os primeiros 20 dias), na regressão intermediária (Rg II -do 21º ao 40º dia), na regressão final (Rg III -do 41º ao 80º dia) e na fase de recuperação ou de repouso II (R II -do 81º ao 150º dia). O experimento foi realizado do final de janeiro (verão-dias longos) a maio (outono-dias curtos

Gonadal steroids levels and vitellogenesis in the formation of oocytes in Prochilodus lineatus (Valenciennes) (Teleostei: Characiformes)

“…A gradual increase in GSI values following the ovarian maturation process has been widely reported for a number of rheophilic species, including Piaractus mesopotamicus (Gazola & Borella, 1997), Pseudoplatystoma fasciatum Leonardo et al, 2006;Romagosa, 2010), Pseudoplatystoma sp. (Dabrowsky et al, 2008), Salminus hilarii (Honji et al, 2009) and Prochilodus argenteus (Arantes et al, 2010).…”

Intestinal histomorphology in Pseudoplatystoma fasciatum fed bovine colostrum as source of protein and bioactive peptides

“…Therefore, research on farmed striped catfish performance, behavior and physiology is yet understandably recent and relatively scarce (Leonardo et al, 2004(Leonardo et al, , 2006Romagosa et al, 2003 a, b). Although intestinal anatomy and histology of striped catfish had already been described by Rodrigues et al (2009), there is a lack on studies on the species' intestinal absorptive mechanisms.…”

Atresia Folicular en Ovarios de Prochilodus lineatus

“…Los folículos atrésicos de P. lineatus predominaron en los meses de febrero a mayo en ejemplares con RGS inferior a 6,5%, y en estadio folicular posvitelogénico. Se señaló que la atresia puede presentarse en cualquier momento del desarrollo oocitario (Ganias et al, 2008 ;Leonardo et al;Miranda et al), sin embargo en cautividad, lo más común es que aparezca en las fases de vitelogénesis y preovulatoria (Bromage & Cumaranatunga, 1988;LinaresCasenave et al, 2002;Miranda et al). En algunas especies, los factores más importantes que determinan el destino hacia la ovulación o la atresia de los folículos son la capacidad de respuesta a gonadotropinas, la capacidad de producir estradiol (Bao & Garverick, 1998;Braw-Tal & Roth, 2005;Garverick et al, 2002;Webb et al, 1999), la participación del sistema de factor de crecimiento insulinoide (IGF) (Rivera & Fortune, 2003a, 2003b) y el medio endocrinológico en el que se desarrollan (Webb et al).…”

“…La atresia es un proceso de degeneración y reabsorción de folículos ováricos que ocurre de manera normal en los ovarios de todos los vertebrados, incluidos los peces. Oocitos atrésicos pueden presentarse tanto en peces de vida silvestre como en los que permanecen en cautiverio (Ball, 1960;Saidapur, 1978;Leonardo et al, 2006) y pueden observarse en todos los estadios del ciclo reproductivo, aunque lo más común es observarlos durante el periodo de post-desove (Miranda et al, 1999;Guraya, 1994). En teleósteos, la atresia puede ser inducida por stress, confinamiento, feromonas, estímulos visuales y táctiles, agentes biocidas, contaminación, radiación, inanición, niveles hormonales inadecuados y cambios en las características del ambiente como luz, temperatura, corrientes de agua (Leino et al, 2005;Nagahama, 1983;Zanuy & Carrillo, 1987).…”