Apoptosis of gut-associated lymphoid tissues in rainbow trout Oncorhynchus mykiss after incubation with Candida albicans and bacterial lipopolysaccharide.

Until now a few studies have been carried out on the gut lymphoid system in fish despite its protective role in the host. Here, we have evaluated the effects of Candida albicans (Ca) and lipopolysaccaride (LPS) on the pyloric and terminal segments of gut in the rainbow trout Oncorhynchus mykiss. In particular, data show that both Ca and LPS are able to cause apoptosis of intestinal lymphoid cells as detected by the terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) procedure. These findings suggest a further modality of gut response in fish to environmental antigens.