ABSTRACT
Six experiments were conducted to examine possible neurotoxic effects of the exposure to contaminants in Lake Ontario salmon administered through the diets of rats. Rats were fed different concentrations of fish (8%, 15% or 30%) in one of three diet conditions: Lake Ontario salmon, Pacific Ocean salmon, or laboratory rat chow only. Following 20 days on the diets, rats were tested for five minutes per day in a modified open field for one or three days. Lake Ontario salmon diets consistently produced significantly lower activity, rearing, and nosepoke behaviors in comparison with ocean salmon or rat chow diet conditions. A dose-response effect for concentration of lake salmon was obtained, and the attenuation effect occurred in males, females, adult or young animals, and postweaning females, with fish sampled over a five-year period. While only two of several potential contaminants were tested, both fish and brain analyses of mirex and PCBs relate to the behavioral effects.
Subject(s)
Brain Diseases/chemically induced , Food Contamination , Motor Activity/drug effects , Salmon , Water Pollutants, Chemical/toxicity , Water Pollutants/toxicity , Analysis of Variance , Animals , Brain Chemistry/drug effects , Female , Fresh Water , Great Lakes Region , Male , RatsABSTRACT
To determine what behavioral changes are caused by consumption of Lake Ontario salmon, a 30% diet of Lake Ontario or control Pacific Ocean salmon was fed to rats for 20 days. In Experiments 1 and 2 (preference-for-predictability E-maze test), rats fed Lake Ontario salmon developed a preference for predictable food rewards more quickly than did the control rats. In Experiments 3 (passive avoidance) and 4 (conditioned suppression), rats fed Lake Ontario salmon suppressed responding to food far more after the introduction of mild electric shocks than did control rats. All results supported the hypothesis that ingestion of Lake Ontario salmon, contaminated with polychlorinated biphenyls, mercury, lead, etc., increases the reactivity of rats to aversive events. The results were successfully simulated by DMOD, a mathematical model of learning, using the assumption that rats fed Lake Ontario salmon find unpredictable nonreward and mild shock more aversive.
Subject(s)
Arousal/drug effects , Avoidance Learning/drug effects , Feeding Behavior/drug effects , Salmon , Taste/drug effects , Water Pollutants, Chemical/toxicity , Water Pollutants/toxicity , Animals , Appetitive Behavior/drug effects , Discrimination Learning/drug effects , Male , New York , Orientation/drug effects , Rats , Rats, Inbred StrainsABSTRACT
A study of the hearing of the penguin Spheniscus demersus, in terms of the cochlear potentials, showed sensitivity over a range at least of 100 to 15,000 Hz, with the best sensitivity in the region of 600 to 4000 Hz. The form of the sensitivity function is consistent with the vocalizations of these animals. In general, this species of penguin shows good agreement with other birds in both the form and range of auditory sensitivity.
