Structural analysis of the Pimelodus maculatus (Lacépède, 1803) embryogenesis (Siluriformes: Pimelodidae)

Abstract

The fish embryonic development comprises the events between the egg fertilization up to larvae hatching, being useful for the identification of viable eggs in productivity and survival studies as well as in raising experiments of several species. The goal of the present study was to characterize the embryonic development of Pimelodus maculatus (Siluriformes; Pimelodidae). The embryogenesis was typical of teleosteans, but with differences in relation to other species such as duration of development, type of blastocoel, moment of somite segmentation among others. Six stages of embryonic development were defined: zygote, cleavage, blastula, gastrula, organogenesis (divided in phases: early segmentation and late segmentation) and hatching with a period of incubation equal to 13 hours at 29 ºC and 17 hours at 25 ºC. The extruded oocytes presented a mean diameter of 812 m before and 1066 m after hydration. When fertilized, they presented a yellowish coloration and a gelatinous layer surrounding the chorion. The cleavage pattern is described as: 2; 4; 8 (4x2); 16 (4x4); 32 (4x8) and 64 (2x4x8) blastomeres up to morula phase (+64 cells). It was also possible to observe at this phase, the beginning of the formation of the yolk syncyctial layer (YSL). Afterwards, the blastula and gastrula stages followed. The end of gastrula was characterized by the formation of the yolk plug. Subsequently, the differentiation between cephalic and caudal regions began, along with the embryo elongation, structuring of optic, Kupffer's and otic vesicles besides a previously unidentified structure in the yolk syncyctial layer. The end of this stage is typified by the tail detachment. The late segmentation phase was distinguished by a free tail, presence of more than 30 somites, optic and otic vesicles, development of posterior intestine, pigmentation of cephalic and caudal regions of yolk sac and embryo growth. The recently-hatched larvae presented a primordial digestive tract, quite evident and pigmented eyes, closed mouth, encephalic vesicles and a mean length of 3410 m. O desenvolvimento embrionário de peixes compreende eventos que ocorrem desde o ovo fertilizado à eclosão das larvas, podendo auxiliar na identificação dos ovos viáveis em estudos de produtividade e sobrevivência, como também nas pesquisas de cultivo desses animais. O objetivo do presente estudo foi caracterizar o desenvolvimento embrionário do Pimelodus maculatus (Siluriformes; Pimelodidae). A embriogênese foi característica de teleósteos, apresentando variações que difere de outras espécies como, tempo de desenvolvimento, tipo da blastocele, momento de segmentação dos somitos, entre outros. Seis estágios de desenvolvimento embrionário foram definidos: zigoto, clivagem, blástula, gástrula, organogênese (dividido em fases: segmentação inicial e segmentação final) e eclosão com período de incubação de 13 horas à 29ºC e de 17 horas à 25ºC. Os ovócitos extrusados apresentaram diâmetro médio de 812 m antes da hidratação e após 1066 m. Após a fertilização, apresentaram colo...

Morphofunctional transformations of the yolk syncytial layer during zebrafish development

“…C,D, and A,B,C). It is also thin in P. maculatus during segmentation (Buzollo et al, ). The YSL characteristics that will remain quite constant till the 3–4 dpf or even later are establiahed at the 14‐somite stage when the yolk extension is formed (Fig.…”

“…The ultrastructure of the YSL has been described in the embryos of Fundulus heteroclitus (before and during epiboly; Lentz and Trinkaus, ; Trinkaus and Lentz, ; Bailey, ; Betchaku and Trinkaus, ), Oryzias latipes (up to hatching; Yamamoto, ; Kageyama, ), Perca fluviatilis (up to hatching; Krieger and Fleig, ), Prochilodus lineatus (up to hatching; Ninhaus‐Silveira et al, ), Pimelodus maculatus (up to hatching; Buzollo et al, ), Sebastes schlegeli (at the stage that corresponds to prehatching in F. heteroclitus; Shimizu and Yamada, ), in embryos (from the establishment of «vitelline» vascular system) and in the larvae of Salmo gairdneri (Vernier and Sire , b; Sire et al, ) and in the larvae of Salmo trutta morpha fario, Hippoglossus hippoglossus, Gadus morhua, Dicentrarchus labrax, Stizostedion lucioperca, Sparus aurata, Scophthalmus maximus, Pleuronectes platessa, Osteoglossum bicirrhosum (Walzer and Schönenberger, 1979a,b; Kjørsvik and Reiersen, ; Morrison, ; Mani‐Ponset et al, ; Poupard, 2000; Skjarven et al, ; Jaroszewska and Dabrowski, ). The developmental histology of the YSL has been studied in the embryos of Oncorhynchus keta (Nishida, ,b), in the larvae of Salmo irideus, O. keta, Hypomesus olidus, Leuciscus idus , S. lucioperca (Yamada, , b; Ostaszewska et al, ; Ostaszewska, ) and in both embryos with yolk sac and larvae of P. fluviatilis , Pterophyllum scalare and Coregonus alpinus (Kunz, ).…”

Embryonic development and larval stages of Steindachneridion parahybae (Siluriformes: Pimelodidae): implications for the conservation and rearing of this endangered Neotropical species

“…In this study, we identified the embryonic and larval development stages according to the descriptions established for other Siluriformes studied so far (Cardoso et al, 1995;Buzollo et al, 2011) and also by Nakatani et al (2001) and Richards (2006).…”

“…Pseudoplatystoma fasciatum (Leonardo et al, 2004), Pseudoplatystoma corruscans (Campos, 2005), Rhamdia quelen (Baldisseroto & Neto, 2005), Pimelodus maculatus (Buzollo et al, 2011), Pauliceia luetkeni, and Iheringichthys labrosus . Furthermore, reproductive status of broodstock when reared under different rearing systems and hormonal treatment (hormone stimulation techniques to induce ovulation and spermiation) of Pimelodidae species were also described (Batlouni et al, 2006;Andrade et al, 2010;Romagosa, 2010).…”

Morphological development of Corydoras aff. paleatus (Siluriformes, Callichthyidae) and correlation with the emergence of motor and social behaviors

“…Post-hatching development of Siluriformes has deserved many studies which illustrate a wide variety of developmental adaptation strategies, from species without true larval phases (lima et al, 2012) to other exhibiting many post-hatching phases, similar to the species of our study, as shown in the cascadu, Hoplosternum littorale (Hanckock, 1828) by ramnarine et al (1994). Taking into account exclusively the Pimelodidae family, a great variety of developmental stages, phase names and incubation times can be found, including hatching times as short as 14-16 h as reported by Buzollo et al (2011) andnogueira et al (2012), 30 h (Pereira et al, 2006), 50 h (honJi et al, 2012 and extremely prolonged incubations, as found in some marine catfishes (lima et al, 2012). It is generally accepted that in most teleosts, larger eggs will produce, as a rule, larger larvae with larger yolk sacs and therefore, more developed organisms at hatching (sanches et al, 1999).…”