Hematological parameters and phagocytic activity in fat snook (Centropomus parallelus) bred in captivity Antenor Aguiar Santos a, b, c, * ,1 , Maria José T. Ranzani-Paiva d , Marcelo Leite da Veiga e , Lucas Faustino f , Mizue I. Egami g, h,1 a UNIFESP/EPM, SP, Brazil b Morphology Department, Adventist University Center of São Paulo, UNASP, Brazil c Laboratory of Environmental Impact and Histopathology, Adventist University Center of São Paulo, UNASP, Brazil d Fishery Institute, Av. Francisco Matarazzo, 455, CEP 05001-900, São Paulo, SP, Brazil e Morphology Department of the Federal University of Santa Maria, Brazil f Department of Immunology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil g Morphology Department, Histology Division, UNIFESP-EPM, SP, Brazil h Comparative Hematology Laboratory, UNIFESP-EPM, SP, Brazil article info Article history: Received 4 April 2012 Received in revised form 6 August 2012 Accepted 8 August 2012 Available online xxx Keywords: Hematology Phagocytosis Season Sex Centropomus parallelus abstract The objective of this work was to determine the hematological parameters and the phagocytic capacity of peritoneal macrophages of fat snook related to sex, stage of gonadal maturation and seasonal cycle. Blood was collected from 135 animals (78 females and 57 males) and used for determinations of: erythrocyte number, hematocrit, hemoglobin, erythrocyte indices mean corpuscular volume (MCV) and mean corpuscular hemoglobin concentration (MCHC), total and differential leukocyte counts, and thrombocyte count. The phagocytic capacity and phagocytic index were determined after Saccharomyces cerevisiae inoculation in the peritoneal cavity of the animals. The hematological results according to sex showed that the erythrocyte, total leukocyte and thrombocyte counts were statistically higher in males than females, with the latter showing a higher MCV. Concerning to erythrocyte count, hematocrit and hemoglobin concentration analyzed separately by sex and stage of gonadal maturation, males were found to have significantly elevated values in the mature stage and decreased levels in the resting stage. The results of the erythrocyte and leukocyte series, thrombocytes and phagocytic activity related to seasonal cycle showed significant differences in both sexes, where hematocrit and hemoglobin concentration were lower in winter and higher in the other seasons, mean corpuscular volume was higher in the summer and lower in the winter and fall, total leukocytes and thrombocytes lower in the spring and higher in the fall, lymphocytes low in the winter and summer and high in the spring and phagocytic capacity and phagocytic index high in the summer and low in the winter and fall. The results showed that the hematological values in males are statistically higher than those in females, the erythrocyte values in males increase with the progression of gonadal maturation and that winter is the season of the year least favorable for hematological and phagocytic responses for survival of fat snook kept in captivity. The parameters studied could be utilized in the evaluation of the health status of this species in captivity. Ó 2012 Elsevier Ltd. All rights reserved. 1. Introduction The fat snook, Centropomus parallelus belongs to the family Centropomidae, and is distributed from the southeast of Florida (USA) to Florianopolis in southern Brazil [1e3]. This fish species can inhabit coastal waters, estuaries, brackish lagoons, freshwater environments and occasionally even salt ponds (hypersaline) [4]. It has delicate white meat and is part of a high-cost market, and it is also much appreciated for sport fishing. Moreover, this species shows many biological aspects that are favorable for aquaculture. The fat snook is euryhaline, estuarine-dependent, gregarious, tolerant to high densities, resistant to eutrophic water, and fast growing. It also has highly efficient food conversion ratios (FCRs) and energy utilization, has the potential for very high biomass * Corresponding author. R Sócrates Abrahão, 16 C 15 e Vila Munhoz, CEP 05782- 470, São Paulo, SP, Brazil. Tel.: þ55 11 58165630; fax: þ55 11 99287477. E-mail address: antenorbio@gmail.com (A.A. Santos). 1 Federal University of São Paulo, Paulista School of Medicine, CEP 04023-4000, Brazil. Contents lists available at SciVerse ScienceDirect Fish & Shellfish Immunology journal homepage: www.elsevier.com/locate/fsi 1050-4648/$ e see front matter Ó 2012 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.fsi.2012.08.005 Fish & Shellfish Immunology xxx (2012) 1e9 Please cite this article in press as: Santos AA, et al., Hematological parameters and phagocytic activity in fat snook (Centropomus parallelus) bred in captivity, Fish & Shellfish Immunology (2012), http://dx.doi.org/10.1016/j.fsi.2012.08.005