This study describes the hematological alterations in Astyanax altiparanae associated with infestation with Lernaea cyprinacea. The study was carried out in a lagoon of the MogiGuaçu River, in the municipality of Pirassununga, in the state of São Paulo, Brazil. Of 46 fish examined, 45.6% had their integument infested by L. cyprinacea, with a mean intensity of 4.9 parasites per fish and a mean abundance of 2.2, giving a total of 139 recovered crustaceans. The abundance of L. cyprinacea correlated positively with the length and weight of the hosts, and the intensity of infestation was higher in female hosts. Macroscopic observation of lesions associated with the parasite showed a severe inflammatory reaction around the site of attachment of L. cyprinacea, associated with a lower relative condition factor and blood parameters. The hematocrit, number of red blood cells and thrombocytes were higher in non-parasitized than in parasitized fish. However, the hemoglobin concentration, hematimetric indices and the number of white blood cells were not influenced by infestation.
KEY WORDS: Ectoparasites · Hematology · Infestation · Continental fish
Resale or republication not permitted without written consent of the publisherDis Aquat Org 120: [77][78][79][80][81] 2016 Gallio et al. , Raissy et al. 2013). Often such damage can lead to secondary infections caused by bacteria and fungi in hosts (Gabrielli & Orsi 2000, Thatcher 2006, Gallio et al. 2007, Raissy et al. 2013. Heavy infestations may cause mass mortalities of wild and farmed fish and make the fish undesirable to anglers, thus affecting fishery management targets (Thatcher 2006, Raissy et al. 2013. L. cyprinacea was introduced to Brazil along with carps imported from Hungary, and presently these parasites can be found infesting diverse wild fish populations in various hydrographic basins of the country (Medeiros & Maltchik 1999, Gabrielli & Orsi 2000, Gallio et al. 2007).In fish populations, blood parameters can be important tools for understanding the physiology and oxygen carrying capacity, as well as the immune system, of fish , Ranzani-Paiva et al. 2013. Therefore, blood cell parameters may be good indicators of the health status of a fish population (Nair & Nair 1983, Ranzani-Paiva et al. 2013. However, few studies have addressed the effects of the infestation of parasitic crustaceans on the hematological parameters of fish (Nair & Nair 1983, Silva-Souza et al. 2000, TavaresDias et al. 2007, Fajer-Ávila et al. 2011, Peña-Rehbein et al. 2013). This study investigated the effect of moderate levels of infection by L. cyprinacea on the hemato logical parameters of A. altiparanae from the Mogi-Guaçu River, part of the upper Pa raná River basin (Brazil).
MATERIALS AND METHODSIn August 2012, 46 specimens of Astyanax altiparanae were caught in a lagoon of the Mogi-Guaçu River, in the municipality of Pirassununga, in the state of Sao Paulo, Brazil (21°55' 55'' S, 47°22' 37'' W) (Fig. 1). Fish were caught with gillnets of different meshes (5, 10 and 12 mm) ...