Oogenesis inLaetacara araguaiae(Ottoni and Costa, 2009) (Labriformes: Cichlidae)

Abstract

We aimed to analyze the oogenesis of adult females of the cichlid fish Laetacara araguaiae. The specimens' gonads were removed and processed for light and transmission electron microscopy. Oogenesis in L. araguaiae showed the following characteristics: a germinal epithelium with three types of oogonia (A-undifferentiated, A-differentiated and B-oogonia), oocytes at meiotic prophase stage and ovarian follicle formation. Oocytes showing primary growth with pre-vitellogenic and cortical alveolus were observed. Similar to data for other cichlids, oocytes in secondary growth or vitellogenesis were characterized by the initial deposition of yolk microgranules. The event that characterizes the maturation stage is nucleolus migration, also called the germinal vesicle, to the oocyte periphery in the direction of the micropyle. The follicular complex undergoes several changes throughout the oocyte stages. To the best of our knowledge this study is the first to describe L. araguaiae oogenesis. Moreover, this study is the first step to better understand the reproductive biology of this species, which shows great potential for use as an ornamental fish.

Oocyte growth, follicular complex formation and extracellular-matrix remodeling in ovarian maturation of the imperial zebra pleco fish Hypancistrus zebra

“…zebra were found individually or in nests. This organization pattern is the same as in Laetacara araguaiae 10 , Pseudotocinclus tietensis 12 and Astyanax altiparanae 21 . This arrangement in nests occurs through projections of follicular cells that separate the nests of other oogonia scattered through the germinal epithelium 22 .…”

“…zebra the subdivision of the zona radiata is related to the variation in the size of the pore canals (Zr1 and Zr2) and the presence of microvilli (Zr3). Some investigators have established that this layer functions to transport substances and provide resistance to abrasion 10 , 31 . H .…”

“…These modifications occur in the layers that surround the oocyte, for example the zona radiata, follicular cells, basement membrane and theca, and together with the mature oocyte form the follicular complex, FC 9 . The FC is important for reproduction and is observed in different orders, Labriformes 10 , Perciformes 11 and Siluriformes 12 . However, information concerning the emergence of the layers that form this complex is limited for teleost fishes.…”

Ovarian cycle in Devario aequipinnatus with emphasis on oogenesis

“…Folliculogenesis begins with the proliferation of the oogonia, and the differentiation of the oocytes occurs later (Grier, 2000, 2012; Andrade et al ., 2001; Grier et al ., 2007; Mazzoni et al ., 2010). For D. aequipinnatus these modifications are observed and follow the pattern of other teleost orders, specifically Siluriformes and Labriformes (Quagio-Grassiotto et al ., 2011; Santos-Silva et al ., 2015).…”

New occurrence of a non-native ornamental cichlid in the Paranapanema River, southern Brazil

“…Taking into account that this species reaches the first gonadal maturation with 20 mm standard length (Santos-Silva et al, 2015), off the total captured, one fish was juvenile and eight were adults. Since the first detection in December of 2013, this species became more frequent in other samples.…”