Uptake of Vibrio anguillarum bacterin in the posterior intestine of rainbow trout Oncorhynchus mykiss, sea bass Dicentrarchus labrax and turbot Scophthalmus maximus after oral administration or anal intubation

Abstract

The intestinal uptake of Vibrio anguillarum bacterin was studied in rainbow trout Oncorhynchus mykiss (Richardson) sea bass Dicentrarchus labrax (L.) and turbot Scophthalmus maximus (L.) using 2 delivery methods: oral administration (OA) and anal intubation (AI). At selected time intervals after antigen administration (from Day 1 to Day 21) fish were killed and sectioned for histology. The location of the bacterin was determined by staining intestinal, kidney, and spleen sections using the indirect fluorescent antibody technique. Antigen uptake was observed only in the posterior intestine of the vaccinated fish; antigen was never detected in the anterior kidney and spleen sections. The Vibrio bacterin was detected in the lamina epithelialis for up to 21 d following delivery. After AI the fluorescence was stronger than after OA regardless of species. Some differences in the bacterin uptake occurred among the fish species. The implications of these differences are discussed.