Early development of Astronotus ocellatus under stereomicroscopy and scanning electron microscopy

Astronotus ocellatus, popularly known as Oscar, is a cichlid fish from the Amazon basin (Brazil) with a great potential for fish farming. The aim of this research is to describe the morphology of eggs and larvae of A. ocellatus under stereomicroscopy and scanning electron microscopy. Eggs from natur...

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Bibliographic Details
Published in:Zygote (Cambridge) 2012-08, Vol.20 (3), p.269-276
Main Authors: Paes, Maria do Carmo Faria, Makino, Lilian Cristina, Vasquez, Leonardo Avendaño, Fernandes, João Batista Kochenborger, Nakaghi, Laura Satiko Okada
Format: Article
Language:English
Subjects:
Animals
Astronotus ocellatus
Brazil
Cichlidae
Embryo, Nonmammalian - metabolism
Embryo, Nonmammalian - ultrastructure
Fishes - embryology
Fishes - growth & development
Freshwater
Hydrogen-Ion Concentration
Larva - metabolism
Larva - ultrastructure
Microscopy, Electron, Scanning
Temperature
Zygote - growth & development
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Summary:Astronotus ocellatus, popularly known as Oscar, is a cichlid fish from the Amazon basin (Brazil) with a great potential for fish farming. The aim of this research is to describe the morphology of eggs and larvae of A. ocellatus under stereomicroscopy and scanning electron microscopy. Eggs from natural spawnings were taken to hatcheries, collected at previously established time periods and then analysed. Oscar's eggs are demersal, adhesive and fragile to touch, with a slightly oval shape. The fertile eggs are yellowish in colour and when unfertilized are a white opaque colour. In the initial collection (IC), the majority of eggs were found to be at the gastrula phase with 30% epiboly. At 12 h after the IC, the formation of the embrionary axis and somites was observed, followed by differentiation of the tail and of the head. Fifteen hours after the IC, the emergence of the optic and otic vesicles, and of adhesive glands and the yolk pigmentation was observed. Larval hatching took place between 46 and 58 h after the first collection, at an average temperature of 27.45 ± 2.13°C. The larval stage was characterized by the development of the heart, fins, branchial apparatus, neuromasts, taste buds and adhesive glands on the head. Larval development to yolk absorption took a period of 257 h. These results provide important information for reproduction, rearing and preservation of A. ocellatus.
ISSN:0967-1994
1469-8730
DOI:10.1017/S0967199411000116