Structural and ultrastructural analysis of embryonic development ofProchilodus lineatus(Valenciennes, 1836) (Characiforme; Prochilodontidae)

Abstract

SummaryThis survey was performed to characterize the embryogenesis of Prochilodus lineatus. Seven stages of embryo development were identified -zygote, cleavage, blastula, gastrula, segmentation, larval and hatching -after a period of incubation of 22 h (24• C) or 14 h (28 • C). The following cleavage pattern was identified: the first plane was vertical (2 blastomeres); the second was vertical and perpendicular to the first (4 blastomeres); the third was vertical and parallel to the first (4 × 2); the fourth cleavage was vertical and parallel to the second (4 × 4); the fifth was vertical and parallel to the first (4 × 8); and the sixth cleavage was horizontal (64 blastomeres • C); 11.0-13.0 h (28 • C)) showed a free tail, more than 25 somites, an optic vesicle and a ready-to-hatch larval shape. The blastomeres at cleavage stage had disorganized nuclei indicating high mitotic activity. At gastrula, the blastomeres and the periblast had euchromatic nuclei and a large number of mitochondria and vesicles. The yolk was organized into globose sacs, which were dispersed into small pieces prior to absorption.

Toxicity of cryoprotectants on Prochilodus lineatus (Valenciennes, 1837) (curimba) embryos in an experimental incubator (Characiformes: Prochilodontidae)

“…This was observed for curimba embryos in average temperatures of 24°C and 28°C, where hatching occurred 22 and 14 h after fertilization, respectively (Ninhaus et al, 2006). As the temperatures were very close to the comfort range, our larvae took less time to hatch, but the incubation maintained the viability of the larvae, which was observed in satisfactory development rates.…”

“…The initial and final doses of hormone given were 0.5 and 5 mg/kg of fish and 0.4 and 4 mg/kg of fish, for females and males respectively. The application of the hormone was done intramuscularly, with a syringe of 1 mL and near the base of the dorsal fin, at intervals of 12 h (Murgas et al, 1997;Ninhaus-Silveira et al, 2006).…”

Brycon gouldingi(Teleostei, Characidae): aspects of the embryonic development in a new fish species with aquaculture potential

“…In B. gouldingi, the anterior region of the neural tube was expanded, giving rise to anterior brain (prosencephalon), medium brain (mesencephalon) and posterior brain (rhombencephalon) as described in D. rerio by Kimmel et al (1995), G. morhua by Hall et al (2004), P. lineatus by Ninhaus-Silveira et al (2006) and by Marques et al (2008) in P. corruscans.…”

Observation of the embryonic development in Pseudoplatystoma coruscans (Siluriformes: Pimelodidae) under light and scanning electron microscopy

“…Morrison et al (2001) suggested that variations in the embryonic development rate and in the embryonic development (asynchrony and malformation) are related to the incubation period and breeder's age. Kimmel et al (1995), Morrison et al (2001) and Ninhaus-Silveira et al (2006) showed that, even within a fertilized spawning incubated at optimal conditions, there is some asynchrony in the embryonic development time.…”

“…Cleavage started from the centre towards the blastodisc margin Shardo, 1995). Successive cleavage took place up to the 65 blastomere stage and as long as the number of blastomeres increased, their size decreased (Wourms & Evans, 1974;Castellani et al, 1994;Ninhaus-Silveira et al, 2006). We observed that morula stage in the P. coruscans is followed by the blastula stage, which is characterized by the blastoderm formation and, then, by the gastrula stage, when epiboly movements begin (Leme dos Santos & Azoubel, 1996), which extends up to the closure of the blastopore by the blastoderm and formation of the tail button (Kimmel et al, 1995).…”