Morphological and cytochemical characteristics of neutrophil in common carp（Cyprinus carpio), Nile tilapia（Oreochromis niloticus）and striped grunt（Parapristipoma trilineatum）were examined by light microscopy. Three types of granules, eosinophilic granule（αG), chromophobic granule（βG）and basophilic granule（γG）were observed in the neutrophils of these fish species. Multiple Romanowsky-type stain valuation revealed that αG of these fish species were stained eosinophil with May-Grünwald（MG), but not with Giemsa. Eosinophil of the αG was disappeared by Giemsa after MG. The βGs were unstained by Romanowsky-type stain and peroxidase positive. The γG of common carp and striped grunt were stained light blue with Giemsa, but not MG. On the other hand, the γGs of Nile tilapia were stained not only with Giemsa, but also with MG. Furthermore, the γGs of Nile tilapia were toluidine blue positive, but those of common carp and striped grunt were negative.
Cyprinus carpio
Oreochromis niloticus
Parapristipoma trilineatum
neutrophil
morphology
cytochemistry