Caracterização comparativa do intestino das espécies da Ordem Xenarthra

Abstract

RESUMO.-O sucesso na manutenção de uma espécie depende de vários fatores entre eles a eficiência digestiva, sendo assim parâmetros morfométricos do tubo digestório são necessários para o conhecimento dos processos digestivos dos alimentos no organismo animal além de indicar a preferência alimentar de uma espécie. Este trabalho visou descrever morfologicamente os intestinos delgado e grosso, órgãos do sistema digestório de representantes da ordem Xenarthra a fim de fornecer subsídios para a avaliação da dieta e realização de procedimentos clínicos nestes animais, Morphometric parameters of the digestive tract are required for an understanding of the digestive processes of the food in the animal organism, besides indicating the feeding preference of specie. This study aimed to describe morphologically the small and large intestines, organs of the digestive system of representatives of Xenarthra order to provide data for the evaluation of diet and conduct clinical procedures in these animals, whether free-living or captive. At this research, were used in total 7 specimens from three-toed sloths (Bradypus torquatus), nine-banded armadillo (Dasypus novemcinctus) and giant anteater (Myrmecophaga tridactyla). The intestines of B. torquatus were short and simple, but at the specimens of D. novemcintus and M. tridactyla the intestines were long and had some peculiarities. We notice the presence of Brunner's glands and structures to increase the surface absorption at the duodenum of all specimens. Only in B. torquatus, we notice that the mesentery remains the jejune attached to the dorsal wall of the abdominal cavity. The ileum represented the lower portion of the intestines in all studied specimens except in M.tridactyla. The cecum in D. novemcinctus and M. tridactyla showed considerable size, glands at the mucosa and was full of food debris, indicating that it was functional. In the mucosa of the colon of all specimens had crypts of Lieberkühn, being more numerous in D. novemcinctus and M. tridactyla. Only in B. torquatus, the rectum showed greater diameter and stiffness compared to the colon. In all species studied, we notice a large glandular surface and lots of goblet cells that produce mucus to facilitate defecation. Our results demonstrate that the conformation and structure of the digestive system reflects more the kind of diet and digestive needs of the animal, than to the family he belongs.INDEX TERMS: Anatomy of the digestive tract, Xenarthra, intestine, morphology, histology.

External and digestive system morphology of the Tamandua tetradactyla

“…The jejunum was spiralled and oriented to the right flank, traversing the entire perimeter of the cavity, crossing the median plane near the urinary vesicle, traversing the left flank and returning to the right antimer and forming a single ring; this also corroborates the description by Macedo () for the species and giant anteater (Carvalho et al, ). According to those authors, the mesothelium is long and “fan‐shaped” allowing the attachment of a long portion of intestines in a small area.…”

“…This organ was anatomically divided into three portions: duodenum, jejunum and ileum (Figure E). The duodenum was short, consisting of a single descending segment, loosely adhered to the roof of the cavity by a relatively long mesoduodenum, giving this loop atypical freedom, corroborating the description of Carvalho et al () and Macedo () for giant anteater. In the median plane of the body, the duodenum reaches a mesothelin root continuing into the jejunum, and this root is responsible for securing all other segments of the intestine.…”

“…The large intestine of the animals was subdivided into caecum, colon and rectum (Figure F). The caecum was blind‐sided, with “comma” shape, as well as found in giant anteater (Carvalho et al, ), and oscillated between the right, left or medial antimers. In the collared anteaters, the caecum was poorly developed, different from that found in herbivorous animals, such as capybaras (Rodrigues, Fonseca, Paula, & Peixoto, ), in which this organ is complex and voluminous.…”

“…The length of the small intestine (108.05 ± 1.90 cm; Table ) is larger, as well as, for the giant anteater ( Myrmecophaga tridactyla ; 428.5 cm, Ferreira, Souza, Mortoza, & Rezende, ; 775.3 cm, Carvalho et al, ) than that of the sloth ( Bradypus variegatus ; 82.35 cm), which is a strictly herbivorous animal (Estrela, ), also a Xernathra specie. This comparison disagrees with the premise that herbivores (sloths) have a larger intestinal length than carnivores and omnivores, thus demonstrating that insect digestion is not necessarily rapid.…”

Trend Toward Individualization of the Endocrine and Exocrine Portions of the Giant Anteater Pancreas (Myrmecophaga Tridactyla, Xenarthra)

“…Although in Brazil, M. tridactyla shows a high occurrence in some regions, such as the Cerrado (Mourão and Medri, ; Cáceres et al, ; Miranda, ), it is consider a vulnerable species (Brasil, ; IUCN, ; Miranda, ; CITES, 2013). Distinctive physiology related to adaptations of digestive system to feeding (Carvalho et al, ) as well as low body temperature has been related to the limited distribution of M. tridactyla in warmer regions of the Americas (Medri and Mourão, ).…”