Mice exposure to tannery effluents changes their olfactory capacity, and their response to predators and to the inhibitory avoidance test.

The current study has assessed whether the oral and/or dermal exposure of C57Bl/6 J mice to tannery effluent (a complex pollutant consisting of xenobiotic mixtures) could damage their olfactory functions, as well as whether it changes their aversive behavior in the inhibitory avoidance test. Accordingly, the animals were distributed in groups which were exposed or not to this xenobiotic through two different routes (oral and dermal), for 15 days. The effluent group subjected to oral exposure received drinking water containing 5% tannery effluent, whereas the animals in the dermal group were exposed to raw tannery effluent for 1 h/day. The animals dermally exposed to the tannery effluent (males and females) have shown the highest latency to find palatable food in the buried food test. The shortest time spent by the animals (orally or dermally) exposed to tannery effluent in the safety zone of the apparatus used in the predator exposure test, as well as the longest time spent by them in the aversive zone, have shown failures in their perception to the risk represented by the presence of the predator (cat). The passive avoidance test results have shown that the dermal exposure to tannery effluent led to partial memory deficit in male and female mice; therefore, the present study has confirmed the tannery effluent toxicity to mammals. Moreover, the present study was pioneer in demonstrating that the dermal exposure to this xenobiotic, even for a short period-of-time, can change the olfactory and cognitive functions of animals, as well as lead to harmful consequences to their health.