Northern Kentucky University
Digestive Enzyme Activities in Anuran Tadpoles Under Varying Food Conditions.
Institution
Northern Kentucky University
Faculty Advisor/ Mentor
Richard Durtsche
Abstract
Aquatic tadpoles can encounter foods that vary in terms of nutritional value and quality. Studying digestive enzymes of tadpoles gives insight into their capabilities to consume and digest differing foods available at unpredictable intervals. This study compared the digestive enzymatic activities in two tadpole species, the Wood frog (Rana sylvatica) and the American toad (Bufo americanus) exposed to changing diets throughout a 108 hour experimental period after a 12 hour acclimation period. The diets fluctuated from algae (carbohydrate), to shrimp (protein), and back to algae (carbohydrate) with equally divided feeding periods on each food. This investigation is the first to report evidence of digestive enzyme plasticity in larval anurans. We determined that the levels of amylase and trypsin activities varied between species and among time periods, and that both enzymes were more active in B. americanus than R. sylvatica. Pepsin had the lowest specific activities and was not significantly different between species. Lipase did not vary across time periods or between these species throughout the experiment. Trends in the levels of carbohydrase and protease activity varied with different foods consumed across the experimental periods, indicating that enzymatic plasticity is present for these tadpoles as diet shifts. Knowledge of tadpole digestive enzymes can help us decipher the physiological changes that must take place for these animals to reach metamorphosis, when encountering these unpredictable environmental food resources.
Digestive Enzyme Activities in Anuran Tadpoles Under Varying Food Conditions.
Aquatic tadpoles can encounter foods that vary in terms of nutritional value and quality. Studying digestive enzymes of tadpoles gives insight into their capabilities to consume and digest differing foods available at unpredictable intervals. This study compared the digestive enzymatic activities in two tadpole species, the Wood frog (Rana sylvatica) and the American toad (Bufo americanus) exposed to changing diets throughout a 108 hour experimental period after a 12 hour acclimation period. The diets fluctuated from algae (carbohydrate), to shrimp (protein), and back to algae (carbohydrate) with equally divided feeding periods on each food. This investigation is the first to report evidence of digestive enzyme plasticity in larval anurans. We determined that the levels of amylase and trypsin activities varied between species and among time periods, and that both enzymes were more active in B. americanus than R. sylvatica. Pepsin had the lowest specific activities and was not significantly different between species. Lipase did not vary across time periods or between these species throughout the experiment. Trends in the levels of carbohydrase and protease activity varied with different foods consumed across the experimental periods, indicating that enzymatic plasticity is present for these tadpoles as diet shifts. Knowledge of tadpole digestive enzymes can help us decipher the physiological changes that must take place for these animals to reach metamorphosis, when encountering these unpredictable environmental food resources.