Tissue and Cell 43 (2011) 137–142 Contents lists available at ScienceDirect Tissue and Cell journal homepage: www.elsevier.com/locate/tice Hematological characteristics of the spotted rose snapper Lutjanus guttatus (Steindachner, 1869) healthy and naturally infected by dactylogyrid monogeneans O.B. Del Rio-Zaragoza, E.J. Fajer-Ávila ∗ , P. Almazán-Rueda, M.I. Abdo de la Parra Centro de Investigación en Alimentación y Desarrollo (CIAD), A.C., Unidad Mazatlán en Acuicultura y Manejo Ambiental. Av. Sábalo Cerritos s/n, C.P. 82010, A.P. 711, Mazatlán, Sinaloa, Mexico article info Article history: Received 9 September 2010 Received in revised form 6 January 2011 Accepted 7 January 2011 Available online 3 April 2011 Keywords: Hematology Spotted rose snapper Lutjanus guttatus Dactylogyrids monogeneans abstract The aim of the present study was to obtain a basic knowledge of the hematology in order to determine changes in blood parameters of the spotted rose snapper Lutjanus guttatus. The morphological features of blood cells were described according to the observations made by light microscopy of Wright–Giemsa- stained blood films. The reference intervals and the mean value were determined for each hematological parameter evaluated in healthy fish and data were compared to those of naturally infected, with dactyl- ogyrid monogeneans fish. Infected fish showed a prevalence of 100% and a mean intensity of 246.6 parasites per fish. Mean values of HCT, WBC, thrombocytes percentage and eosinophils percentage were significantly higher (P < 0.05) in the infected fish. In addition, lymphocytes percentage and total protein were significantly lower (P < 0.05) in the infected fish compared to healthy fish. Only total WBC count, lymphocytes per- centage and eosinophils percentage in infected fish were outside reference interval. The hematology of the spotted rose snapper of this study might serve as a basis for future studies and diagnosis. Changes observed in blood parameters in infected fish suggest that the immune system of L. guttatus was affected by the presence of the parasites. © 2011 Elsevier Ltd. All rights reserved. 1. Introduction The spotted rose snapper Lutjanus guttatus (Steindachner, 1869) is found in tropical and subtropical waters of the eastern Pacific from Mexico to Peru (Fischer et al., 1995). This is an important commercial fish species that has been in experimental culture for several years in Central America (Gutiérrez-Vargas and Durán- Delgado, 1999; Valverde-Chavarría and Boza-Abarca, 1999). In Mexico there is an increasing interest in spotted rose snapper cul- tivation by important fish sectors. Several grow-out trials are being carried out by more than 17 coastal Pacific fishery cooperatives, based on wild juveniles of snappers, including the spotted rose snapper (Avilés-Quevedo, 2006). The studies for the experimental culture of spotted rose snapper have been developed mainly in the northwest region of Mexico. Nowadays the technology of juvenile massive production is ready to achieve a pilot-scale (Alvarez-Lajonchère et al., 2007). However, the occurrence of ectoparasites has risen as a potential problem ∗ Corresponding author. Tel.: +52 6699898700; fax: +52 6699898701. E-mail address: efajer@ciad.mx (E.J. Fajer-Ávila). for its development. In this regard, the culture of the spotted rose snapper has lead to the increase of several diseases produced by infestation of the ciliated protozoans, i.e. Brooklynella hostilis and Cryptocaryon irritans and a dinoflagellate Amyloodinium ocellatum. The last two groups of organisms attack the skin and gills causing the death of the fish in captivity (Fajer-Ávila et al., 2006). Other abundant and potentially dangerous parasites are the dactylogyrid monogeneans, a heavy infection of which can cause gill epithelial hyperplasia, asphyxia and anorexia of the spotted rose snappers (Fajer-Ávila et al., 2007); and this in turn, might alter the fish blood parameters. Monitoring the health of fishes using hema- tological analysis is especially important as a direct or inferential indicator; because this gives information related to the tolerance to a stressor agent or/and illness of the fish (Schreck and Moyle, 1990; Del Rio-Zaragoza et al., 2008) such as parasites. In order to facilitate such an approach, first it is necessary to thoroughly characterize the blood cells of the organisms and to use this knowledge to quantify normal blood parameters (Shigdar et al., 2007). In the present work, we studied blood parameters of spot- ted rose snapper healthy and naturally infected with dactylogyrid monogeneans to establish the interval which represents the health status of cultured fish. 0040-8166/$ – see front matter © 2011 Elsevier Ltd. All rights reserved. doi:10.1016/j.tice.2011.01.002