Estudos de parâmetros morfométricos do trato gastrointestinal (TGI) são necessários para o conhecimento dos processos digestórios dos alimentos no organismo animal e indicar a preferência alimentar de uma espécie. Foram amostrados, bimensalmente, 100 filhotes capturados aleatoriamente em oito criadouros no município de Diorama, Goiás. O experimento foi conduzido com animais entre 23 a 29 meses de idade, que tiveram seus desempenhos avaliados por medidas biométricas do comprimento retilíneo da carapaça e do peso. Para o cálculo das relações corporais dos órgãos tomou-se como base o peso vivo individual de cinco tartarugas, em cada idade estudada, perfazendo um total de quatro colheitas com 20 exemplares de cada criadouro. As análises de comparação de médias foram realizadas pelo teste de Duncan. Os resultados indicaram que o estômago representou maior percentual do trato digestório, com 44,20%, seguido pelo intestino delgado, 28,48%, e o intestino grosso, com 20,93%, baseados na relação corporal com o TGI vazio. O TGI cheio apresentou comprimento médio de 72,75 cm. Para o intestino delgado foi obtida a média de 46,68 cm e para o intestino grosso 14,00 cm. As análises das relações corporais indicaram que o estômago e o intestino delgado apresentaram maior capacidade de armazenamento, sugerindo que desempenham importante função na digestão de alimentos consumidos.
It is necessary to carry out a study that focuses on the morphometrical parameters of the gastrointestinal tract (TGI), which can provide subsidies for getting knowledge about the digestive processes that happen into the animal organism. Bimontly, it was sampled 100 P. expansa hatchlings, which were randomly captured from eight commercial flocks located at the county of Diorama, State of Goiás/Brazil. The experiment was conducted with animals of 23 to 29 months of ages, from which the biometrical measures were taken, in order to evaluate their growth performances. It was taken two biometrical measures, that is, the carapace rectlineal length - in milimeters, and the weight gain- in grams. Aiming at the calculation of the body relationships, it was taken, as a basis, the individual gross weight of five hatchlings, from each one of the studied ages, totalizing an amount of four crops of 20 specimens from each involved commercial flock. The comparison analyses of the averages were accomplished by Duncan test. Based upon the relations between the empty TGI and the whole body, the results pointed out that the stomach corresponded to the major portion of the digestive tract, that reached 44.20% of it. Second, came the small gut, that reached 28.48% of it, followed by the large gut, that reached 20.93% of the digestive tract. The full TGI showed a mean lenght of 72.75 cm. As for the small gut, it was obtained an average length of 46.68 cm and, as for the large gut, it was observed an average lenght of 14.00 cm. The body relation analyses indicated that the stomach and the small gut showed the best storage capacities and, this result suggests that those viscera play an important role in the food digestion.