Anatomia do tubo digestório de tucano toco

Abstract

A study was made of the anatomy of the digestive tract of 12 specimens of Ramphastos toco captured by IBAMA (Brazilian Institute of Environment and Renewable Natural Resources) of Uberlândia, MG. The birds comprised seven males and five females, six adults and six juveniles, with an average total length of 476.33 ± 103.49 mm. The birds’ thoracic-abdominal cavity was opened to examine and identify the components of the digestive tube. The cervical esophagus, situated dorsolaterally to the trachea in the right antimere of the neck, continues as the thoracic esophagus in view of the absence of an ingluvium (craw) in this species. The thoracic esophagus leads ventrally to the lungs, joining the proventricle dorsally to the heart. The proventricle is cylindrical and is located in the left antimere of the cavity. The ventricle, in turn, is rounded and in close contact with the dorsal side of the left hepatic lobe through an impression. The duodenum forms a U-shaped loop and is connected to the ventricle, the right hepatic lobe, and the jejunum-ileum and colon-rectum loops. The largest intestinal segment, the jejunum-ileum, is arranged in loops distributed along the caudal third of the thoracic-abdominal cavity. The large intestine consists solely of the colon-rectum, which circumvents the left kidney ventrally to the cloaca. The cervical esophagus, thoracic esophagus, proventricle, ventricle, duodenum, jejunum-ileum and colon-rectum represent, on average, 17.82%, 12.90%, 5.67%, 6.82%, 27.64%, 30.06% and 11.57%, respectively, of the bird’s total length.