Morphological and cytochemical characterization of the peripheral blood cells of farmed streaked prochilod Prochilodus lineatus (Characiformes, Prochilodontidae)

D.M Cunha,F.A.A Calixto,A.C.B Portugal,R Takata,A.B.M Fonseca,G.R.F.C Martins,E.F.M Mesquita,S.A Uehara,N.R.P Almosny

doi:10.1590/1678-4162-12388

Abstract

ABSTRACT Morphological and cytochemical studies of peripheral blood cells of fish have improved the understanding of their functions and cell types. The present study performed the Morphological and cytochemical analysis of the peripheral blood of Prochilodus lineatus, Characiform native to South America, which has been gaining space in local aquaculture and as a species introduced in Asia. Our analysis provided information on the morphological and cytochemical characteristics of the leukocytes, for the formulation of hypothesis about their role in the immune system of the species. It was found that Prochilodus lineatus has morphological and cytochemical features in common with other fish species, mainly of the Characiformes order. However, we detected the presence of heterophils and PAS positive granulocytes simultaneously with neutrophils. We also found that heterophils and PAS positive granulocytes are very similar, both morphologically and cytochemically.

Highlights

Fish leukocytes are a very heterogeneous group, and there are differences even among closely related species
While some cite the presence of lymphocytes, neutrophils, monocytes and eosinophils (Tavares Dias et al, 2008; Cazenave et al, 2009; Belo et al, 2013; Tavares Dias, 2015), another study reports the presence of these cells and the periodic acid Schiff (PAS) positive granulocyte (Ranzani Paiva et al, 1999)
PAS positive granulocytes have been reported in Characiformes species – Piaractus mesopotamicus, Colossoma macropomum (Tavares Dias et al, 1999a, 1999b, 2003; Tavares Dias, 2015) and in Cypriniformes species Aristichthys nobilis (Tavares Dias, 2006) and Cyprinus carpio (Tavares Dias et al, 2003; Cazenave et al, 2009), whose morphology is similar to what has been reported in Prochilodus lineatus in the present study

Summary

Introduction

Fish leukocytes are a very heterogeneous group, and there are differences even among closely related species These cells are less differentiated in comparison to their mammal counterparts, making their identification more difficult (Shigdar et al, 2009). For a better characterization of these cells and elucidation of their role in fish, techniques that demonstrate their enzymatic profile and/or structural components are necessary, since they differ among leukocyte subpopulations and maturation stages. In this regard, cytochemical staining and morphological analysis can provide additional information that enables the identification of leukocyte subpopulations and their likely functions (Shigdar et al, 2009)

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