Effects of dietary PCBs and nonyl-phenol on immune function and CYP1A activity in channel catfish, Ictalurus punctatus

Polychlorinated biphenyls (PCBs) induce CYP1A, modulate immune responses, and may have endocrine disruption properties. Many coastal ecosystems and their tributaries contaminated with PCBs also receive sewage out-fall effluents containing detergents such as nonyl-phenol (NP). Because NP has estrogenic properties and modulates P4501A activity, and because estrogen modulates immune function in a variety of vertebrates, studies to investigate interactions of PCBs and NP are needed. Channel catfish ( Ictalurus punctatus) (25–30 g) were fed seven different diets containing 10 ppm Aroclor 1254 (PCB), 10 ppm NP, Wppm PCB + 10 ppm NP, 100 ppm PCB + 10 ppm NP, 10 ppm PCB + 100 ppm NP, 100 ppm of each, or carrier. After 7 and 21 days of treatment peripheral blood hematocrits, total serum protein and immunoglobulin, antigen-specific antibody, anterior kidney phagocyte oxidative burst, and gut/liver cytochrome P4501A protein/EROD, were evaluated. Phagocyte function was enhanced by low NP on day 7 and low PCB + high NP on day 21. Gut and liver P4501A protein/EROD were greatly induced by combinations of high PCB + high and low NP. Treatments did not effect hematocrits, serum protein or total immunoglobulin on either day or antibody titers on day 21 against formalin-killed Edwardsiella ictualuri (day 14 post sensitization).