ABSTRACT
The gastrointestinal tract of the alpaca (Vicugna pacos) is most efficiently adapted to its habitat at high altitudes. Alpacas, just like ruminants, feed on hardly digestible forage. However, it has been demonstrated that the anatomy of the camelid digestive tract has developed independently of ruminants and not in homology to them. Despite a long history of domestication and an increasing number of animals worldwide, little research has been done on the intestinal anatomy of alpacas. The purpose of this study was to describe the anatomical features of the alpaca's intestines and to explain anatomical peculiarities in the context of evolutionary function and morphology. Another goal of this study was the demonstration of weaknesses of the intestinal anatomy predisposing alpacas to certain clinical presentations. Six animals were used for dissection. The basic structure of the intestines was comparable to that in ruminants. However, a number of characteristic peculiarities were found in alpacas, like the duodenal ampulla and the proximal and distal loop of the ascending colon. The jejunum and ileum, unlike those of ruminants, had their own mesentery largely separated from the ascending mesocolon. The main blood supply was provided by the cranial and caudal mesenteric artery. The particular lymph nodes were located along the branches of these two arteries. The spiral colon seemed to play a major role in intestinal digestion and water resorption. The size of the distal fermentation chamber allows the presumption that alpacas belong to the group of animals practicing a fractionated fermentation in the proximal and distal fermentation chambers. Anat Rec, 301:1840-1851, 2018. © 2018 Wiley Periodicals, Inc.
Subject(s)
Adaptation, Physiological/physiology , Ecosystem , Feeding Behavior/physiology , Intestines/anatomy & histology , Intestines/physiology , Animals , Camelids, New World , Female , MaleABSTRACT
A morfofisiologia relacionada à absorção de ácidos graxos voláteis (AGV) ao longo do trato gastrintestinal de ruminantes não é totalmente caracterizada. Desse modo, os objetivos deste trabalho foram mensurar a extensão da superfície de absorção e determinar o índice mitótico (IM) do abomaso, do ceco e da alça proximal do cólon ascendente (APCA). Dez bovinos mestiços adultos tiveram seu estômago e intestino grosso removidos imediatamente após o abate. A área total da superfície de absorção foi mensurada por meio de digitalização e análise de imagens. Cortes histológicos foram feitos para determinação do IM. A superfície absortiva do abomaso, 0,58m², foi menor (P<0,01) do que a do rúmen, 6,53m², e a do omaso, 2,31m². A superfície absortiva do ceco e da APCA, 0,23m², correspondeu a 3,5% da superfície do rúmen e a 10% da superfície do omaso. O IM observado foi 0,48%; 0,14%; 0,36% e 0,41% para as regiões de pregas espirais, pilórica, ceco e APCA, respectivamente. Observou-se correlação positiva entre a massa tecidual do abomaso e a área de superfície de absorção, aspecto também observado no ceco-APCA. Foi possível estabelecer regressões para facilitar a mensuração da superfície absortiva do abomaso e do ceco-APCA.
The morphology and physiology related to volatile fatty acid (VFA) absorption throughout the gastrointestinal tract of ruminants is not totally characterized. The purpose of this work was to measure the abomasum and cecum-colon absorptive surface extension and determine the mitotic index (MI). Ten adult crossbred bovine had their stomach and large intestine removed after slaughter. The total area of the absorptive surface was measured through image capture and analysis. Histological sections were performed to measure the MI. The abomasum absorptive surface (0.58m²) was lower (P<0.01) than that of the rumen (6.53m²) and omasum (2.31m²). The cecum-colon absorptive surface (0.23m²) corresponded to 3.5% of the rumen and 10% of the omasum. The MI observed was 0.48%; 0.14%; 0.36% and 0.41% for the regions of spiral folds, pyloric, cecum and proximal loop of ascending colon, respectively. A positive correlation between abomasum tissue mass and the abomasum absorptive surface was observed. This phenomenon has also occurred in the cecum and colon. It was possible to establish regressions to facilitate measurements of the absorptive surface of the abomasum and cecum-colon.
