Influence of pH on physiological and behavioral responses of Pomacea canaliculata

The physiological and behavioral responses of Pomacea canaliculata exposed to different pH values (4, 5, 6, 7, 8, 9, and 10) were evaluated. Survival, behavior (avoidance), metabolites (mantle), net ion fluxes (Na⁺ and K⁺), and ATPase activity (gills) were the parameters analyzed. The final survival rates were 100% (pH 4-9) and 90% (pH 10), and the groups did not differ significantly. Avoidance behavior was not identified in animals exposed to an extreme pH compared to pH 7. The main changes observed in the metabolites were in those exposed to an alkaline pH. Glucose (pH 9) and total protein (pH 9 and 10) levels increased, and lactate decreased (pH 9 and 10) compared to a neutral pH. There was an increase in Na⁺ efflux at pH 4, 5, and 8 and an influx at pH 9 and 10. Extreme pH values (4 and 10) also caused an increase in K⁺ efflux. At pH values outside the neutrality range (pH 7), there was a significant decrease in the activities of Na⁺/K⁺-ATPase (4, 5, 6, 9, and 10) and H⁺-ATPase (pH 4, 5, 9, and 10). Variations in environmental pH did not cause statistically significant mortality or avoidance behavior in P. canaliculata at the analyzed times. However, due to changes in energy metabolism (glucose and lactate, mainly) and ionoregulation, these can be considered sensitive biomarkers of stress in this species.