Origem e principais ramificações das artérias mesentéricas cranial e caudal em avestruz (Struthio camelus Linnaeus, 1758)

The mesenteric arteries of birds are important for the irrigation of the digestive tract and are associated with weight gain and food conversion. This study aimed to describe the origins, skeletopy, measures and main branches of cranial and caudal mesenteric arteries in ostriches. Forty-one cadavers of ostrich chicks, 23 males and 18 females, obtained from a farmer after natural death. The cadavers were fixed with 10% formaldehyde solution and their vascular system was filled with colored Petrolatex® S-65. The cranial and caudal mesenteric arteries and its proximal branches were dissected in situ and measured with a digital caliper. The mesenteric artery had an average length of 3.68cm±1.04 and emerged from the descending aorta at the level of the eighth thoracic vertebra in most cases; it branched into jejunal and ileocecal arteries. The jejunal artery sent a mean of 14 (14.04±2.08) branches to the jejunum. The ileocecal artery sent a rectal branch and another branch that irrigated ileum, cecum and rectum. In a male specimen the ileocecal artery was originated from the celiac artery. The caudal mesenteric artery emerged in the terminal portion of the descending aorta predominantly at the level of the 4th and 6th sacrocaudal vertebrae. Near the caudal end of the kidney it issued the cranial and caudal branches. The first irrigated the rectum and anastomosed with the rectal branch of the cranial mesenteric artery; the second irrigated the final part of the rectum, cloaca and cloacal bursa. There was no significant difference (p