Myxobolus sp. (Myxozoa) in the circulating blood of Colossoma macropomum (Osteichthyes, Characidae)

Patricia Oliveira Maciel,Elizabeth Gusmão Affonso,Luis Antonio Kioshi Aoki Inoue,Marcos Tavares-Dias,Cheila De Lima Boijink

doi:10.1590/s1984-29612011000100018

Abstract

Myxosporea parasitize many organs in fresh and saltwater fish. Species of the genus Myxobolus parasitizing the gills and other organs of the tambaqui Colossoma macropomum have been described. In the present study, blood smears were made from juvenile tambaqui and were stained with May Grunwald-Giemsa-Wright in order to identify myxozoan parasites. Out of a total of 36 fish examined, one specimen (2.7%) that was reared in a cage presented spores that were identified as M. colossomatis, whereas fish kept in 250 L tanks showed prevalence of 5.5%. This is the first report of M. colossomatis in the blood of farmed tambaqui in the Amazon region. These results indicate that myxozoan parasites should also be investigated in fish blood smears. Some myxosporean species may cause diseases in fish, and these species need to be identified so that adequate preventive sanitary control can be instituted.

Highlights

The tambaqui (Colossoma macropomum) is one of the mostconsumed fish in the central Amazon region
These results indicate that myxozoan parasites should be investigated in fish blood smears
The blood smears from the tambaqui in the cage system and in the laboratory (PVC tanks) revealed that spores with two polar capsules were present

Summary

Introduction

The tambaqui (Colossoma macropomum) is one of the mostconsumed fish in the central Amazon region. For this reason, it is sensitive to diminished natural stocks in the areas surrounding large cities like Manaus, and this favors fish farming on a variety of scales, as a commercially profitable alternative (ROUBACH et al, 2003). As well as being the third most farmed species in Brazil, it is the native species most reared in the Northern. Myxobolosis of the tambaqui, caused by Myxobolus colossomatis, was first found in Brazil by Molnár and Békési (BÉKÉSI; SZÉKELY; MOLNÁR, 2002). With the aim of contributing towards the knowledge of parasitic diseases among tambaqui in captivity, the present study investigated blood smears to diagnose and identify myxosporean parasites

Material and Methods

Findings

Results, Discussion and Conclusion