Histomorphometric study of the prenatal Development of the Circumvallate Papillae of one-humped camel (<i>Camelus dromedarius</i>)

Abstract

This study aimed at investigating the prenatal development of camel circumvallate papillae using standard histomorphometric methods. In the experiment, fifteen Camelus dromedarius foetuses obtained from Sokoto metropolitan abattoir at different gestational ages were used for the study. The fetuses were weighed and grouped according to their gestational ages which were estimated using their crown-vertebral-rump length. From the fifteen tongues used for the study, five belonged to the foetuses being in the first trimester of prenatal development, five came from the second trimester and the next five from the third trimester. A total of ten foetuses were males and five were females. In all stages of development, the tongues were elongated, with flattened and rounded apex .At the first trimester, the tongues were almost uniform width and thickness throughout the length. They were uniformly pinkish, withoutpigmentation and no visiblelingual papillae. At the second trimester, the tongues were observed to have taken the normal shape of an adult tongue with variable size and shape of lingual papillae; tapering rostrally from the root to the apex. Biometrically, the weight of the foetuses were found to be 0.18±0.05 to 21.70±7.28 kg from the first to the second trimester, the crown – vertebral – rump – length were found to be 15.75±4.42 to 94.00±2.83cm from the first trimester to the third trimester, weight of the head were found to be 25.05±15.17 to 1120.00±14.14g and weight of the tongues were found to be 0.79±0.22 to 116.25±11.49g from first trimester to third trimester. Histological observations showed that the circumvallate papillae were coveredwith keratinized stratified squamous epithelium, which was composed by basal, spinosum, granulosum and corneum layers. Lingual glands were located in the deeper parts of the papillae. The surface of the epithelium was less keratinised compared to that of the surrounding surface except the peripheral parts of the papilla. Dermal inter-digitations of variable sizes into the epidermis were observed along the whole surface. Few taste buds were observed along the medial papillary wall epithelium of the small-sized papillae.