Histology of digestive system in the larval and juveline stages of the mullet Mugil platanus Günther, 1880 (Osteichthyes, Mugilidae

Authors

  • Márcia Santos Nunes GALVÃO Pesquisador Cientifico (Bolsista CAPES) -  Seção de Maricultura -  Divisão de Pesca Marí­­tima -  Instituto de Pesca -  CPA/SAA
  • Nelsy FENERICH-VERANI Profa. Dra. -  Depto. De Hidrobiologia -  Centro de Ciências Biológicas e da Saúde -  UFSCar
  • Naoyo YAMANAKA Pesquisador Cientifico -  Seção de Maricultura -  Divisão de Pesca Marí­­tima -  Instituto de Pesca -  CPA/SAA
  • Idili da Rocha OLIVEIRA Pesquisador Cientifico -  Seção de Maricultura -  Divisão de Pesca Marí­­tima -  Instituto de Pesca -  CPA/SAA

Keywords:

development, digestive system, mullet, Mugil platanus, histological technics, histochemical

Abstract

The aim of this paper was to characterize the functional and structural development of the digestive system in larval to young stages of the mullet Mugil platanus through histological and histochemical technics. Fishes from 1 to 60 days old were reared in Mariculture laboratories of the Instituto de Pesca. The samples were embedded in historesin and sections of 2 µm thickness were produced by ultra-microtome. The sections were stained with HE and toluidine blue to observe the general structure of the tissues, Alcian Blue (pH=0.5 and 2.5) and PAS were employed to detect glycosaminoglicans. The digestive tract of the newly hatched larva is a straight, simple and undifferentiated tube. Three days after hatching, the mouth opens, starting the exogenous feeding and so the tract begins to be differentiated into buccopharinge, esophagus and intestine. In esophagus, the first mucous cells were observed between 18 and 21 days, presenting acid nonsulphated mucins. The gastric glands appear at the 38th day. Near the 40th day, it is possible to observe in the stomach 3 segments: cardiac, corpus and pyloric. The pyloric portion presents a thick muscle layer and a triturant surface similar to a gizzard, making easy the mechanical digestion. The posterior intestine enterocytes show large spherical eosinophilic incIusions in supranucIear region, as result of the protein macromolecules pinocytosis. The first goblet cells in intestine appear at the 48th day, presenting neutral and acid mucins. The early development of the mullet M. platanus digestive system is very slow, making difficult the replacement of the live food by artificial diets before the 40th day of life.

Published

2018-09-25

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