Short-Term Estivation and Hibernation Induce Changes in the Blood and Circulating Hemocytes of the Apple Snail Pomacea canaliculata

Abstract

States of natural dormancy include estivation and hibernation. Ampullariids are exemplarybecause they undergo estivation when deprived of water or hibernation when exposed to very lowtemperatures. Regardless of the condition, ampullariids show increased endogenous antioxidantdefenses, anticipating the expected respiratory burst during reoxygenation after reactivation, knownas ?Preparation for Oxidative Stress (POS)?. In this work, we tested the POS hypothesis for changesin the blood and hemocytes of the bimodal breather Pomacea canaliculata (Ampullariidae) induced atexperimental estivation and hibernation. We described respiratory (hemocyanin, proteins, lactate),antioxidant (GSH, uric acid, SOD, CAT, GST), and immunological (hemocyte levels, ROS production)parameters. We showed that, although the protein level remains unchanged in all experimentalgroups, hemocyanin increases in response to estivation. Furthermore, lactate remains unchangedin challenged snails, suggesting an aerobic metabolism during short-term challenges. Blood uricacid increases during estivation and arousal from estivation or hibernation, supporting the previouslyproposed antioxidant role. Regarding hemocytes, we showed that the total populationincreases with all challenges, and granulocytes increase during hibernation. We further showed thathibernation affects ROS production by hemocytes, possibly through mitochondrial inhibition. Thisstudy contributed to the knowledge of the adaptive strategies of ampullariids to tolerate adverseenvironmental conditions.