Comparative oocyte morphology and early development in three species of trahiras from the São Francisco River basin, Brazil

Abstract

Oocyte morphology, embryogenesis and early larval development were compared in Hoplerythrinus unitaeniatus, Hoplias lacerdae and Hoplias malabaricus (Characiformes: Erythrinidae) by macroscopical, histological, histochemical and ultrastructural analyses. The eggs of the three species were yellowish and adhesive, containing carboxyl and sulphate radicals in the glycoconjugates of the zona radiata. A complex surface arrangement was identified in oocytes of H. unitaeniatus and H. lacerdae, while H. malabaricus had a simple oocyte surface pattern. Lectin histochemistry revealed different carbohydrate terminal residues in cortical alveoli, outer zona radiata and follicular cells of the three species. At the animal pole, the oocyte surface topography surrounding the micropyle was species-specific. The micropylar cell was ConApositive, suggesting the presence of carbohydrates with mannose/glucose terminal residues that could have a role during fertilization. The erythrinids exhibited a prolonged embryonic and larval development compared to other Characiformes, a reproductive strategy used for increasing offspring protection. Early development proceeded most rapidly in H. unitaeniatus, followed by H. malabaricus and then H. lacerdae, which could have more developed parental care behaviour. An adhesive organ composed of secretory prismatic cells protruding from the cephalic region of the three erythrinid larva allowed them to attach to one another during development. Reproductive behaviour and early developmental strategies were similar in the three species, but the oocyte surface morphology suggests a close relationship between H. unitaeniatus and H. lacerdae.

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

“…The cement gland, or adhesive organ, is found on the dorsal and lateral head region of some fish larvae and is important to attach the larvae to a substrate during early development (Sato et al, 2003b;Gomes et al, 2007). In this work, the larvae of L. alexandri did not present a larval adhesive organ; the absence of an adhesive organ is a common feature in the larvae of some Siluriformes species (Sato et al, 2003b;Sampaio & Sato, 2006;Santos et al, 2013).…”

Morphologic analysis of developmental phases and gill ontogenesis in neotropical species Poecilia vivipara (Cyprinodontiformes: Poeciliidae) exposed to different salinities

“…The presence of yolk in the post-natal period is comparable to the correspondent phase of development of species that present external fertilization, such as Leporinus piau (Fowler, 1941), Gadus morhua (Linnaeus, 1758), and Prochilodus lineatus (Valenciennes, 1847) (BORÇATO et al 2004, FALK-PETERSEN 2005, NINHAUS-SILVEIRA et al 2006, GOMES et al 2007. In these species, the yolk remains are the reserves of energy used by the larvae in the first hours of life, until they are able to find their own nutrition source.…”

A new vision of the origin and the oocyte development in the Ostariophysi applied to Gymnotus sylvius (Teleostei: Gymnotiformes)

“…Gymnotus sylvius is a freshwater ostariophysian fish in which the oocyte does not possess lipid droplets. Several other species of ostariophysians also do not possess lipid droplets (Bazzoli & Rizzo, 1990;Gomes et al, 2007;Martins et al, 2009). Also in Gymnotus sylvius, the hydrolysis and hydration of the yolk preceding ovulation is modest as expected for fish that produce benthophil eggs (LaFleur et al, 2005).…”

“…The structural aspects of folliculogenesis and most of the cellular events appear to be constants throughout oocyte evolution in fish, and the origin of ovarian follicles is precisely identical between Gymnotus and Centropomus and other fish species . However, the studies regarding Gymnotus sylvius, and other freshwater Ostariophysi (Bazzoli & Rizzo, 1990;Gomes et al, 2007;Martins et al, 2009) have shown some significant differences in egg morphology from other studied fish. In an attempt to have a schema that could also be applied to the ostariophysians, a schema from Quagio-Grassiotto et al (2009) is been presented (Fig.…”