Reproductive apparatus and gametogenesis of Lophiosilurus alexandri Steindachner (Pisces, Teleostei, Siluriformes)

Abstract

The gonad morphology and gametogenesis of Lophiosilurus alexandri Steindachner, 1877 from Santo Antônio river (Minas Gerais, Brazil) were studied through anatomical and histological techniques. Examination of the testis revealed that they were paired, fringed organs with two distinct regions: cranial spermatogenic and caudal spermatogenic and secretory. The cranial region represents ca. 60% of the mature/maturing testis, containing 41 to 73 fringes, while the caudal portion represents ca. 40% and contains 44 to 68 fringes. At the cranial portion the length of the fringes was 3.70 ± 1.70 mm and in the caudal portion was 0.20 ± 0.10 mm. The spermatogenesis was cystic, synchronic, and occurred throughout the whole extension of the seminiferous tubules. The ovaries were saculiforms, paired organs, which present ovigerous lamellae containing cells of the oogenic lineage. The oocytes were classified into four developmental stages according to their cytological characteristics and the characteristics of the cell layers that surround them.

Induced spawning and reproductive variables of the catfish Lophiosilurus alexandri Steindachner, 1876 (Siluriformes: Pseudopimelodidae)

“…The gonad morphology of L. alexandri was similar to those described for pacamã from the Santo Antônio River, Minas Gerais, Doce River basin (Barros et al, 2007). However, in the present study, histological ovary sections from the females that were induced to spawn had vitellogenic oocytes exhibiting nucleus migration toward the mycropilar apparatus in the region of the animal pole.…”

“…Essential biological information about wild populations, such as reproductive cycles, fecundity, and fertility, are needed to manage native and endangered species and for aquaculture purposes (Sato et al, 1998;Sato et al, 2003a;Caneppele et al, 2009;Arantes et al, 2011). Although L. alexandri is potentially useful in aquaculture and important in sport and craft fishing, only a few studies about its reproductive biology have been published, and they describe the reproductive apparatus, gametogenesis, and adhesive eggs (Rizzo et al, 2002;Barros et al, 2007). In the present study, L. alexandri responded well to treatment with CPH; the rate of positive responses in females submitted to hypophysation (75%) was high compared to other Siluriformes species: 58.3% in Pseudoplatystoma corruscans (Sato et al, 2003a) and 67% in Trachelyopterus galeatus (Santos et al, 2013), or was similar to 70.4% in Pimelodus maculatus (Sato et al, 1999), 71% in Rhamdia sapo (= Rhamdia quelen) (Espinach Ros et al, 1984), 75% in Pseudopimelodus charus, and 80% in R. quelen (Sampaio & Sato, 2006).…”

WITHDRAWN: Histological and ultrastructural characteristics of the testis of the invasive suckermouth sailfin catfish Pterygoplichthys disjunctivus (Siluriformes: Loricariidae) from Marikina River, Philippines

“…Testis morphology and ultrastructure of the P. disjunctivus in this study appeared similar to those of relative species, Liposarcus anisitsi (Cruz et al, 2005) and R. aspera (Agostinho et al, 1987) The absence of seminal vesicles in P. disjunctivus is also apparent in related species-L. alexandri and R. aspera, Iheringichthys labrosus, and P. maculates where the origin of secretion can be attributed to secretory cells located in the epithelium of the testes' caudal region (Santos et al, 2001;Barros et al, 2007;Melo et al, 2011). Testicular morphology and ultrastructure of the gonads for hypostominae has not been explored fully.…”

Analyses of the development and glycoproteins present in the ovarian follicles of Poecilia vivipara (Cyprinodontiformes, Poeciliidae)

“…The morphological change observed in the follicular epithelium indicates alteration in its role during oogenesis. In Lophiosilurus alexandri (Steindachner 1877), Barros et al (2007) reported that these cells synthesize certain glycoconjugates that promote the adherence of the eggs to the substrate when they are secreted on their surface. In the guppies, due to the internal fertilization, there is no adherence of the eggs; therefore, the secretory activity of the follicular epithelium cells in this species is probably important for the mechanical protection of the eggs.…”