Effects of Dietary Restriction on PCB Congener Dynamics and Their Association with Health in Channel Catfish

Polychlorinated biphenyls (PCBs) have adverse health effects on organisms, including disruption of the immune, reproductive, endocrine, and nervous systems. Although banned in the United States in the late 1970s, PCBs are persistent in the environment due to their propensity to bioaccumulate thus remaining a threat to environmental and human health. Even though PCBs have been extensively studied over the past several decades, there remains uncertainty regarding the dynamics of specific PCB congeners in aquatic organisms. Much of this uncertainty stems from earlier studies relying on measures of total PCBs to assess health effects instead of evaluating individual congener dynamics. To reduce this uncertainty, we performed an experiment to examine the effects of lipid depletion on congener dynamics, immune function, cortisol production, and macrophage aggregate presence in channel catfish (Ictalurus punctatus). We exposed channel catfish to PCBs using a short-term dietary exposure until fish met an approximate 5ppm body burden; this was then followed by an 8 week food deprivation period.  Congener concentrations were quantified in fillet and liver tissue at time zero, 4, and 8 weeks during the deprivation period. Immune function, cortisol levels, and macrophage aggregate presence were assessed at these time points as well. We will present results from this experiment describing tissue-specific congener dynamics and their effects on biomarkers of immune and endocrine function in channel catfish.