Effects of Environmental Stressors on the Hematological Indices of Some Freshwater Teleosts

  • Nellie Lopez

Abstract

Changes in blood values were observed in young adult freshwater fishes exposed to environmental stressors. Clarias batrachus (TL=221-391 mm; 68.7-371.4 g) starved for 34, 47 and 53 days showed significant reductions in lymphocyte counts. Lymphocyte percentages decreased while neutrophil percentages increased in starved fish. Oreochromis niloticus (TL=105-172 mm; 19.1-77.6 g) exposed for 30 days to 10 and 20 ppm ZnSO4 concentrations at pH 6.7-7.2 showed consistent reductions in total WBC and lymphocyte counts but insignificant changes in RBC-related values. O. niloticus (TL=56-124 mm; 4.0-21.7 g) exposed for 96 h to 10, 20, and 30 ppm ZnSO4 concentrations showed a general tendency of reduction in RBC-reIated values and total and relative WBC counts.

Exposure of O. niloticus (TL=56-106mm; 2.9-14.2 g) for 96 h to 5, 10, and 20 ppm ZnSO4 at low ph (ph 3.1-3.8) elicited marked increases in neutrophil counts and reductions in lymphocyte and RBC counts. O. niloticus (TL=94-154 mm; 13.2-54.4 g) subjected to 24 h and 48 h crowding showed increased hematocrit, neutrophilia, and lymphopenia. In Ophicephalus striatus (TL=259-306 mm; 123.2-192.8 g) stressful effects of crowding and handling were less evident from the blood values obtained after 24 hand 48 h exposure.
Published
2007-10-16
Issue
Vol 4 No 2 (1992)
Section
Articles
Submission of a manuscript implies: that the work described has not been published before (except in the form of an abstract or as part of a published lecture, review, or thesis); that it is not under consideration for publication elsewhere; that its publication has been approved by all co-authors, if any, as well as by the responsible authorities at the institute where the work has been carried out; that, if and when the manuscript is accepted for publication, the authors agree to the automatic transfer of the copyright to the publisher; that the manuscript will not be published elsewhere in any language without the consent of the copyright holders; that written permission of the copyright holder is obtained by the authors for material used from other copyrighted sources; and that any costs associated with obtaining this permission are the authors’ responsibility.