Moments of induced spawning and embryonic development of Brycon amazonicus (Teleostei, Characidae)

Abstract

Based on the economic and ecological relevance of Brycon amazonicus, the goal of this work was to describe the diameter of oocytes and eggs of this species, as well as the chronological embryonic development. The material was provided by Buriti fish farm, Nova Mutum - MT, Brazil. Samples of both oocytes and eggs were obtained from extrusion to hatching. The material was fixed and measured under stereomicroscope, and the samples were divided for light microscopy or scanning electron microscopy (SEM) analyses. At extrusion, the oocytes were bluish green. The frequency distribution of oocytes revealed that 87.7% of them ranged from 1.11-1.30 mm in diameter. During incubation, the total diameter of the eggs increased from 1.22 ± 0.04 mm to 3.06 ± 0.46 mm in the first 60 min post fertilization (PF), and growth ceased at 180 min PF. Between 10-30 s PF, most eggs were fertilized and fertilization cones were observed from 10 s onwards after gamete activation. The main fertilization events took place asynchronically and spermatozoa were visualized in the micropyle vestibule up to 90 s PF. The first cell was formed in the centre of the blastodisc 20 min PF. The morula stage was identified 2 h PF and, 3 h later, 70% of the yolk was covered by the blastoderm; the blastopore was almost entirely closed at 6 h PF. The cephalic and caudal regions of the embryo could be defined 8 h PF and hatching occurred after 13 h of embryonic development. The larvae hatched with undifferentiated organic systems and with a large yolk sac, free from swimming abilities or visual acuity.

Embryonic and larval development of Brycon amazonicus (SPIX & AGASSIZ, 1829)

“…The morphological and morphometric characteristics of dry fertilized eggs and hydrated eggs were similar to those reported in other studies using Brycon (Bernardino et al, 1993;Lopes et al, 1995;Romagosa et al, 2001; Clavijo-Ayala and Arias Castellanos 2004; Nakaghi et al, 2013). The matrinxã's pattern of development is similar to that reported by Kimmel et al (1995) for zebra fish, in which the blastoderm is formed by a single outer layer of flattened cells, known as the involucral outer layer, and a more rounded deep layer of cells.…”

“…Epiboly starts with the deep layer cells radially intercalating and the yolk cell "doming," which was recorded by Andrade-Talmelli et al (2001) and Paes (2008) when eggs presented with 30% epiboly and by Kimmel et al (1995) and Sampaio (2006) when it was in the 50% epiboly stage. With B. amazonicus, Clavijo-Ayala and Arias Castellanos (2004) observed the early gastrula (10% epiboly) at 5 h AF (27.5 ± 0.2 °C), and Nakaghi et al (2013) observed the beginning of the epiboly and gastrula stage when cell proliferation covered approximately 30% of the yolk, at 3 h AF (28.08 °C). We observed the same event 1 h 20 min AF (29.9 ± 0.18 °C), and the difference could be related to temperature.…”

“…The matrinxã's pattern of development is similar to that reported by Kimmel et al (1995) for zebra fish, in which the blastoderm is formed by a single outer layer of flattened cells, known as the involucral outer layer, and a more rounded deep layer of cells. The increase of Faustino et al, 2007;Paes, 2008;Nakaghi et al, 2013).…”

Morphological and morphometric aspects of early life stages of piabanhaBrycon gouldingi(Characidae)

“…The sequence of events observed during embryogenesis of B. gouldingi was similar to that reported for other species of Brycon , such as piabanha Brycon insignis Steindachner 1877 (Andrade‐Talmelli et al ., ), B. cephalus (Lopes et al ., ; Romagosa et al ., ), B. orbignyanus (Reynalte‐Tataje et al ., ), jatuarana Brycon amazonicus (Spix & Agassis 1829) (Nakaghi et al ., ) and other teleosteans such as hybrids of P. corruscans × P. fasciatum (Faustino et al ., ) and P. lineatus (Ninhaus‐Silveira et al ., ). In general, the basic developmental mechanisms of teleosteans are similar and only differ in the chronology of events (Falk‐Petersen, ).…”

Embryonic and Morphological Development of Larvae and Juvenile of the Buenos Aires Tetra, Hyphessobrycon anisitsi (Pisces Characidae) Characidae Fishes

“…In other countries, antioxidant defense capacity against ammonia stress (Pan et al, 2011), the early development of skull (Vandewalle et al, 2005), embryo development (Nakaghi et al, 2013;Weber et al, 2012), etc. have been studied.…”