An in vitro assay to measure phagocytosis in striped bass hybrids (Morone saxatilis × Morone chrysops)

An in vitro phagocytosis assay was developed for hybrid striped bass (Morone saxatilis×Morone chrysops), using cells collected from the peritoneal cavity of this fish. The findings indicated that: (1) 10 days following a single intraperitoneal injection (1 ml) of Freundʹs incomplete adjuvant (FIA) was an appropriate time for collecting suitable working concentrations (5·3± 4·0×107cells ml−1) of peritoneal phagocytes (83·7±1·5% macrophages) from these hybrids held at 23° C; (2) these cells phagocytosed latex beads (polystyrene microspheres 3·12 μm in diameter) after 30 min of in vitro incubation at room temperature (25±1° C). The phagocytic ability and phagocytic capacity in a washed adherent layer exposure system were 67·2±2·76% and 4·14±0·35 beads phagocyte−1, respectively. results strongly suggest that a simple methodology, including baseline data serving as guidelines, is now available for conducting in vitro phagocytosis assays in this hybrid.