BAXTER, N.B.*; DAZLEY, J.S.; SAVAGE, C.; FARMER, C.G.; Univ. of Utah: Apparent Assimilation Efficiency of Various Diets of Juvenille American Alligators Alligator mississippiensis

This study examined the importance of gastroliths to apparent digestive efficiency and time course in American alligators (Alligator mississippiensis). We used 7 juvenile subjects with masses of 0.353 � 0.058 Kg (SEM) throughout the research. The animals were held and fed in water filled aquaria maintained at a temperature of 30 �1 C�. We removed the gastroliths by gastric lavage. X-rays verified that the stones were removed. Diets of mice, crickets, minced crickets, and fish weighing 5% of the alligator body mass were fed in succession roughly two weeks apart and after the animals reached metabolic baseline. The egesta and urine were collected daily in balloons attached to latex sleeve harnesses that were both air-tight and water-tight. The samples were dried to constant weight. Gastroliths were introduced into the aquaria and the animals were allowed to freely ingest them. We analyzed the data and created daily means for the seven animals. We found that the assimilation efficiency was about 91% for all of the diets both before and after the ingestion of gastroliths. There was, however, significant variance in the digestion time by diet. The mouse diet digested the fastest, followed by the fish, and finally the crickets, both whole and minced. Our preliminary results showed a decrease in the time it takes the animals to return to baseline after eating a meal when gastroliths were present compared to digestion without gastroliths, but the differences were not statistically significant.