DefinePK

Abstract

The recent increase interest on the research of various aspects related to the barn owls (Tyto alba) is due to the unique features of the bird in keeping down rodent pests. By identifying the prey fragments in the pellets of indigestible matter that the bird regurgitates it is easy to tell of the diet it consumed to maintain its energy demand. This work seeks to fill the gap on information concerning the gross morphology and morphometric of the alimentary canal of the barn owl (Tyto alba) found in North-central Nigeria. Fifteen apparently healthy Barn Owls of different age groups were used for this work. The live body weight of birds were taken and then euthanized by lethal injection. Dissection was done to gain access to different cavities of the bird for gross anatomic studies of the alimentary canal. The alimentary canal of the three age groups of birds studied presented similar morphological findings. The tongue appeared elongated and triangularly shaped with a pointed tip and a downward projection from the body with a cleft at the middle of the body. There was no crop. The stomach was cone shaped consisting of a cranial glandular compartment and a caudal muscular compartment. A ‘U’ shaped duodenum was clearly visible towards the right side of abdominal cavity, whereas the duodenal loop partly covered the jejunum and ileum. The vitelline diverticulum marks the end of the jejunum and the beginning of the ileum which is the shortest segment of the small intestine. The large intestine consists of two caeca (left and right) and a colorectum. The proximal parts of both caeca were ovoid in shape while the distal part is straight and tiny giving it a microphone or match stick shape. Morphometric measurements of the alimentary canal of the barn owl in the three age groups studied showed a significant difference at P<0.05 on the tongue; stomach and duodenum with emphasis on the adults and owlets. In summary, the decreasing order in length of the different segments of the gastrointestinal tract of the common barn owl studied was found to be: jejunum>duodenum>oesophagus>tongue>ileum>stomach> caecum> colorectum.