Abstract

Hematological and blood chemistry parameters are paramount diagnostic tools for understanding the health dynamics of animals and humans. Due to recent advances in veterinary medicine, well-established reference ranges exist for a number of selected species. Yet, studies exploring the values of these blood components in fish, for research or food purposes, are scant. Availability of information regarding blood parameters in fish could play a crucial role in the early detection of disease, facilitating control strategies for disease outbreaks and ultimately decreasing animal losses. Striped catfish, Pangasius hypophthalmus, is a commercially important aquaculture species in Asia and other parts of the world, but there are no reports on baseline information of its blood parameters. The objective of this work was to establish baseline values for both hematological and blood chemistry parameters, which could contribute to understanding the overall health functions of this catfish species.

Seventy juvenile striped catfish (141.7 ± 41.2 g) were obtained from a commercial supplier and maintained in a 1600 L recirculating aquaculture system and outfitted with an appropriate mechanical and biological filter. The fish were acclimated to tank conditions for 2 months, during which time the fish were maintained at 27.8 ± 0.2°C and fed 3% body weight/day using an automated belt-feeder. For the study, fish were individually netted and anesthetized with 100 mg/L MS-222 (tricaine methanesulfonate), and a non-lethal blood sample collected from the caudal tail vessels. A small sample of blood was immediately transferred to a micro-hematocrit tube, centrifuged, and the packed cell volume and protein concentration determined. The remaining blood was transferred to 0.6-mL tubes containing lithium heparin, the cellular elements separated by centrifugation, and then plasma submitted for clinical chemistry analysis to the Veterinary Teaching Hospital at Virginia Tech. Two weeks later, the same fish were netted and anesthetized with 100 mg/L MS-222, and a small amount of blood was collected from the fish for hematological analysis. Triplicate blood smears were made, air-dried, and standard Wright-Giemsa and Natt-Herrick staining methods were used for leukocyte differential and total blood cell counts, respectively.

The following reference values were obtained for the plasma chemistry parameters: sodium 135–145 mg/dL; potassium 3.4–5.0 mg/dL; chloride 122–132 mg/dL; calcium 11.2–14.5 mg/dL; magnesium 2.5–3.4 mg/dL; phosphorus 4.5–8.4 mg/dL; glucose 87–138 mg/dL; cholesterol 114–204 mg/dL; total protein 3.1–4.1 g/dL; albumin 0.7–1.1 g/dL; globulin 2.2–3.3 g/dL; creatinine 0.0–0.9 mg/dL; and osmolality 246.5–317.5 mOsm/kg. Results from this study constitute the first blood parameter profile for this globally important species of catfish.

* Presenting author