Hematology and Plasma Chemistry Reference Intervals for Cultured Tilapia (<i>Oreochromis</i>Hybrid)

TLDR

Tilapia are a widely farmed fish species, yet their normal physiology and disease responses remain poorly characterized. The study aimed to establish complete hematologic and plasma biochemical reference intervals for production Oreochromis hybrids. Blood from 40 high‑density (120 g L⁻¹) tilapia and 63 plasma samples was analyzed with standard techniques, reference intervals were derived nonparametrically, and the results were compared to those from 15 low‑density (4 g L⁻¹) fish to evaluate environmental effects. Reference intervals for high‑density production tilapia differed in plasma protein, calcium, and phosphorus, indicating they are not applicable to fish raised under alternative density and management conditions.

Abstract

Tilapia are a commonly aquacultured fish yet little is known about their normal physiology and response to disease. In this study we determined the results of complete hematologic (n=40) and plasma biochemical profiles (n=63) in production tilapia (Oreochromis hybrids). The fish were raised in recirculating systems with a high stocking density (120 g/L), and were in the middle of a 15-month production cycle. Blood was analyzed using standard techniques, and reference intervals were determined using nonparametric methods. Non-production tilapia (n=15) from low-density tanks (4 g/L) also were sampled; the clinical chemistry results were compared to reference intervals from the fish raised in high-density tanks. Differences were noted in plasma protein, calcium and phosphorus concentrations, such that reference intervals for high-density production tilapia were not applicable to fish raised under different environmental and management conditions.