The topographic and systematic anatomy of the alpaca stomach.

The gastric anatomy of the alpaca (Vicugna pacos) is adapted to the physiological process of ruminating and the degradation of plant cell wall contents to a great extent. Most alpaca husbandries consist of only few animals and with the still increasing number of alpacas worldwide the number of persons who are responsible for these animals is increasing as well. Despite this, little research has been done with regard to the clinical anatomy of the stomach of alpacas. Six animals were used for dissection. The vascular system of two alpacas was injected with latex milk to illustrate the course of the blood supply to the viscera. One stomach was used to prepare formalin-fixed preparations. The stomach consisted of three compartments (C1-C3) and showed two sacculated areas in C1 and another comb-like system in C2. The compartments were lined by a smooth mucosa. Only the deep cells of C2 were lined by a papillated mucosa. The main blood supply was provided by the coeliac artery which was divided into the hepatic artery and the left gastric artery, supplying abdominal organs like liver, spleen, pancreas, and the initial part of the duodenum. Literature research on the llama stomach showed that the alpaca stomachs that were used resembled each other to a very large degree. The specific design of the stomach together with its related functions and physiological processes confirm that the evolution of Tylopoda and Ruminantia took place in parallel and not in homology.