Comparative Morphology and Morphometry of Blood Cells in Zebrafish (Danio rerio), Common Carp (Cyprinus carpio carpio), and Tilapia (Oreochromis niloticus)

Abstract

Several diagnostic tools are available for veterinarians and fish health professionals to evaluate fish health and their abnormalities. However, reference data regarding the character and size of fish blood cells are limited. The purpose of this study was to analyze the morphology and morphometry of normal blood cells in zebrafish (Danio rerio), common carp (Cyprinuscarpio carpio), and tilapia (Oreochromis niloticus). To get a representative sample, we took blood from ten 6-mo old healthyfish from each species. Fish were purchased from an ornamental fish market and the local government fish breeding centerin Yogyakarta, Indonesia. A total of 100 erythrocytes and a maximum of 30 leukocytes (neutrophils, eosinophils, basophils,lymphocytes and monocytes) were randomly sampled and analyzed qualitatively and quantitatively, including morphometricanalysis of both the long axis (LA) and short axis (SA) of these cells. All data obtained were analyzed using ANOVA statisticaltests to compare the blood cells in each species with SPSS software. The findings revealed distinct differences in bothmorphology and morphometry of the blood cells among the species. Basic knowledge obtained from this research will aidin the development of biomarkers and other ancillary diagnostic tools for further hematology research, conservation, andclinical diagnosis in these 3 fish species.

Application of haematology parameters for health management in fish farms

“…The infantile stage of erythrocytes can be divided into three stages: early, medium and late. 38 Proerythrocytes are large in size, nearly round cells, larger nuclei and less cytoplasm (i.e. large cytoplasmic ratio).…”

“…Lymphocytes accounted for more than 80% of the white blood cells in grass carp, Nile tilapia, and common carp. 25,104,250 Interestingly, in the peripheral blood cells of rohu (Labeo rohita), the neutrophils accounted for a higher proportion of the total number of leukocytes (80.58 ± 0.73%) than lymphocytes (14.74 ± 0.69%). 251 The number of neutrophils in striped catfish, Oreochromis niloticus and Siberian sturgeon was 43.0 ± 0.10%, 30.46% and 22.67 ± 0.33%, respectively.…”

“…The number of eosinophils in fish is approximately 0%-5%, but no eosinophils were found in grass carp, blunt snout bream and other fish. 241,250,251 The number of basophils in fish is even less and these cells are not found in most fish. For example, the number of basophils in Nile tilapia was 2.67 ± 0.33%.…”

“…208 The nuclei are dark blue after Giemsa staining, and the nuclei are large, nearly round and mostly located in the centre, but also biased to one side. 25,250 After Giemsa staining, the cytoplasm of lymphocytes was light blue with relatively large nucleo-cytoplasmic ratio. Many organelles were found in the lymphocytes using electron microscopy.…”

“…However, these studies are far behind those in mammalian blood cells, and there are still some differences in the classification and function of some blood cells. 38,39 However, with the gradual application of modern molecular biology techniques and methods in the study of fish blood cells, some long-debated problems have been clarified or confirmed. Importance has been always attributed to haematology indexes by theorists and practitioners, and thousands of articles have been published on Web of Science and PubMed in recent years (Figure 1).…”