Salmo salar: ultrastructural morphology of chorion, from normal and with hatching problems ova

• Published in: Archivos de medicina veterinaria
• Main Authors: Jaramillo, R., Goicoechea, O., Garrido, O., Molinari, E.
• Format: Article in Journal/Newspaper
• Language: Spanish
• Published: Archivos de Medicina Veterinaria 2009
• Subjects: Salmo salar; reproducción; ultraestructura; corion; reproduction; ultrastructure; chorion
• Online Access: http://revistas.uach.cl/index.php/amv/article/view/4947; https://doi.org/10.4067/S0301-732X2009000100009

Either eyed alevins unable to digest the chorion or those digesting it partially, are both suffering the “hard chorion” phenomenon; in both cases alevins can not survive producing high mortality rates. During recent years, the salmon farming industry in Southern Chile has been facing massive mortality events caused by “hard chorion”. Since “hard chorion” is a recently observed phenomenon there are no literature reporting its origin. The aim of this study was to find differences in the ultrastructure of chorion fibers fromSalmo salarova at different stages of development by using Scanning Electron Microscopy and image analysis technique. Early results here reported indicated no differences in thickness of chorion fibers forSalmo salarova at different stages of development, however differences in spatial arrangement of fibers forming the inner layer of chorion seem to explain the “hard chorion” occurrence. No pores were observed in the inner layer of chorion of ova exhibiting “hard chorion” as opposed to normally developed ova which have pores and allow hatching of alevins. Since choriogenin is a protein formed by a number of sub-units, it is possible that failure in synthesis of one of these sub-units might be responsable for an anomalous arrangement of fibers of chorion causing the “hard chorion” phenomenon. El “corion duro” es un fenómeno de reciente ocurrencia y se caracteriza porque algunos alevines con ojo no son capaces de degradar el corion que les rodea o lo hacen sólo de manera parcial, produciéndose en ambos casos la muerte del alevín. Este fenómeno ha causado fracasos reproductivos importantes en algunas pisciculturas del sur de Chile, desconociéndose hasta ahora la razón de su ocurrencia. En este estudio se realizaron mediciones del grosor del corion deSalmo salarasí como de las fibras que forman parte de éste en ovas fertilizadas, no fertilizadas, con desarrollo normal y ovas que no lograron eclosionar. Los resultadosobtenidos indican que las leves variaciones observadas en el grosor del corion ...