SHORT COMMUNICATION Haematological and biochemical characteristics of male jundia ´(Rhamdia quelen Quoy & Gaimard Pimelodidae): changes after acute stress Leonardo Jose¤ Gil Barcellos 1 , Luiz Carlos Kreutz 1 , Laura Beatriz Rodrigues 1 , Irineo Fioreze 2 , Rosmari Mezzalira Quevedo 2 , Leonardo Cericato 3 , Jaqueline Conrad 3 , Auren Benck Soso 3 , Michele Fagundes 3 , Luciana de Almeida Lacerda 4 & Silvia Terra 4 1 Universidade de Passo Fundo, Faculdade de Agronomia e MedicinaVeterina Ł ria, Campus I, Cx Postal 611, Bairro Sa ì o Jose¤ . CEP 99001-970 ^ Passo Fundo, RS, Brasil 2 Laborato¤ rio de Piscicultura, Universidade de Passo Fundo, UPF 3 MedicinaVeterina Ł ria, Universidade de Passo Fundo, Curso de MedicinaVeterina Ł ria, Campus Universita Ł rio do Bairro Sa ì o Jose¤ , Caixa Postal 611, CEP 99001-970, Brazil 4 MedicinaVeterina Ł ria, Universidade Federal do Rio Grande do Sul. Av. Bento Gonc° alves 9090, Porto Alegre, RS, Brazil, CEP 90000-000 Correspondence: L Jose Ł Gil Barcellos, Universidade de Passo Fundo, Faculdade deAgronomia e MedicinaVeterina Ł ria, Campus I, Cx Postal 611, Bairro Sa ì o Jose¤ . CEP 99001-970 ^ Passo Fundo, RS, Brasil. E-mail: lbarcellos@upf.tche.br The jundia Ł ( R. quelen) is an endemic ¢sh species in South America that can withstand cold winters and grows fast in the summer. In aquaculture systems, at a density of two to four ¢sh per m 2 , it will reach 600^ 800 g body weight in 8 months. Jundia Ł is a suitable species for ¢sh production in the southern part of South America, making it ideal for any region with a temperate or subtropical climate (Barcellos,Wasser- mann, Scott,Woehl, Quevedo, Ittze¤ s, Krieger & Lulh- ier 2001a). According to Wendelaar Bonga (1997), several practices of commercial aquaculture, includ- ing harvest procedure induce a characteristic stress response. According to Stoskopf (1993), the evaluation of blood parameters may be useful to monitor the phy- siological status of ¢sh and for the diagnosis of ¢sh pathologies. The elevation in the concentrations of plasma cortisol is recognized as the principal re- sponse to stressors and is widely used as stressors’ response indicator (Barton & Iwama1991). The aim of the present study was to determine the basal haematological and biochemical levels of sev- eral blood parameters and to evaluate hormonal (cor- tisol) and blood changes after a typically conduced harvest in a 5000 m 2 tank. The e¡ects of stressors in teleost ¢sh have been well de¢ned (Barton & Iwama 1991); however, experiments aiming to evaluate the potential stress e¡ects of some practices of commer- cial aquaculture, in commercially important ¢sh spe- cies, should be tested rather than standardized stressors (e.g. handling with pen nets). The study was conducted at the facilities of the University of Passo Fundo (281 15’S/521 24’’W, 687 m above the sea level). One-year-old adult males R. que- len (500 50 g SEM) were kept in 5000m 2 tank with one ¢sh per m 2 . The mean level of dissolved oxygen during culture was 5.072.0 mg L À 1 and the pH ran- ged between 6.0 and 7.2. The ¢sh were fed once a day with commercially available food (Alisul Rac° o ì es Ltda., Brazil). The basal cortisol concentrations were determined by analysis of blood samples from 12 males at the pond immediately before the water drainage that pre- ceded harvest. For the haematological and biochem- ical determinations, 60 ¢sh were sampled during the culture period. These samples were taken under- Aquaculture Research, 2003, 34, 1465^1469 r 2003 Blackwell Publishing Ltd 1465