Initial development of Prochilodus hartii (Pisces: Prochilodontidae) submitted to induced reproduction

Abstract

The Prochilodontidae prepare for reproduction in captivity, but neither ovulation nor spawning occurs, thus requiring induced reproduction for breeding and restocking. This study analyzed for the first time the embryogenesis and larval ontogeny of P. hartii submitted to induced reproduction by hypophysation with crude common carp pituitary extract. The extrusion of oocytes and sperm was performed manually and fertilization was done using the dry method. After fertilization, the eggs were kept in incubators at 23°C. A stereomicroscope was used to measure egg diameter and to monitor embryo development. Samples of larvae were collected daily for 7 days for histological and biometric analyses. The recently extruded oocytes, non-hydrated, are spherical, grey, and non-adhesive with a diameter of 1480 ± 39 μm and after hydration, have a diameter of 2860 ± 120 μm. The positive response to hypophysation was 100% for females and 80% for males. Spawning occurred 7 h after the third hormonal dosage. The fertilization rate was 77% at 23°C. Blastopore closure occurred at 6 h 45 min and embryonic development was completed 36 h 10 min after fertilization. After 204 h post fertilization (hpf) the larvae reached a standard length of 6.56 ± 0.14 mm with the yolk sac completely resorbed. In P. hartii, the oral cavity opening occurred 132 hpf. The results of this study provide knowledge to better understand induced reproduction, breeding, and management of P. hartii, a species with a high potential for pisciculture, and which is commercially important in the Jequitinhonha River basin.

Early development ofProchilodus nigricansSpix & Agassiz 1829 (Characiformes: Prochilodontidae) in captivity

“…Prochilodus nigricans presents spherical, transparent, semi‐dense, pelagic eggs with ample perivitelline space and a short period of embryonic development, a common characteristic for species of Prochilodus (Abdo et al, 2015; Ninhaus‐Silveira et al, 2006; Souza et al, 2015). After fertilization, rapid hydration and obtaining the ample perivitelline space in Prochilodus eggs is a characteristic related to the reproductive behaviour of migratory fish that present external fertilization and development, without parental care, leaving their offspring free in the water column (Abdo et al, 2015; Arias‐Gallo et al, 2010; Orsi et al, 2016). This characteristic is also observed in other genera of Characiformes with the same reproductive strategy, as in Leporinus piau (Borçato et al, 2004), Piaractus brachypomus (Lima, 2014), Colossoma macropomum (Almeida, 2014), Brycon nattereri (Maria et al, 2017) and Salminus hilarii (Araújo et al, 2020).…”

“…The studies describing the early stages of prochilodontids is limited to species occurring in other basins, such as Paraná (Abdo et al, 2015; Nakatani et al, 2001; Ninhaus‐Silveira et al, 2006; Reynalte‐Tataje et al, 2020; Souza et al, 2015). Only S. insignis has the early life cycle described (Araújo‐Lima, 1985).…”

Ontogenesis and embryogenesis of Megaleporinus elongatus larvae (Characiformes: Anostomidae) from the Jequitinhonha River Basin

“…Blastopore closure occurred at 6 hr 34 min. This embryogenesis stage is important in aquaculture as a sign of fertilisation success, since unfertilised oocytes can parthenogenetically develop until closure of the blastopore (Perini et al, 2010;Perini, Sato, Rizzo, & Bazzoli, 2013;Abdo et al 2016).…”

“…The use of new species in a cultivation system will not be efficient without having knowledge about the embryonic development of the species, allowing comparisons between normal and altered patterns (Gomes et al, 2007;Perini et al, 2010). Several events should be observed during larval development, as they are important for fish farming and taxonomy, such as growth rate, size at hatching, size and time of absorption of the yolk sac, opening of the mouth and intestinal lumen, retinal pigmentation, presence of an adhesive organ, fin development, gill arches and chromatophores (Weber, Sato, Santos, Rizzo, & Bazzoli, 2012;Abdo, Perrotti, Meireles, & Bazzoli, 2016). Several events should be observed during larval development, as they are important for fish farming and taxonomy, such as growth rate, size at hatching, size and time of absorption of the yolk sac, opening of the mouth and intestinal lumen, retinal pigmentation, presence of an adhesive organ, fin development, gill arches and chromatophores (Weber, Sato, Santos, Rizzo, & Bazzoli, 2012;Abdo, Perrotti, Meireles, & Bazzoli, 2016).…”

“…Larval ontogenesis occurs in the post-hatching period. Several events should be observed during larval development, as they are important for fish farming and taxonomy, such as growth rate, size at hatching, size and time of absorption of the yolk sac, opening of the mouth and intestinal lumen, retinal pigmentation, presence of an adhesive organ, fin development, gill arches and chromatophores (Weber, Sato, Santos, Rizzo, & Bazzoli, 2012;Abdo, Perrotti, Meireles, & Bazzoli, 2016).…”