Morphological features of the Egyptian Ossimi sheep tongue: New scanning electron microscopic insights into its papillary system adaptations to Egyptian ecological conditions

Abstract

The current study aims to illustrate the gross and scanning electron microscopic characterizations and ultrastructural adaptation of the lingual papillary system of Egyptian Ossimi sheep to Egyptian ecological conditions. The tongue had three regions: the apex (with a slightly bifurcated tip), the body (subdivided into rostral and caudal parts) and the root (subdivided into rostral papillary and caudal non‐papillary parts). Torus linguae had two parts: the triangular rostral part (the caudal part of the body) and the quadrilateral wide part (the rostral part of the root). The lingual papillary system had mechanical (filiform, conical and lentiform) and gustatory (fungiform and circumvallate) types. Filiform papillae were heavily scattered on the dorsal surface of the apex, the rostral part of the body and the ventral surface of the papillary region of the tip. Filiform papillae had five subtypes (ventral and dorsal processed, triangular, leaf‐like and triangular‐processed papillae), while the conical papillae had three subtypes: two lingual (small, large) and one paralingual (elongated pointed), and the fungiform had two subtypes: the high‐density ovoid (on the ventral surface of the tip) and round papillae (on the dorsal surface) that possessed a high number of taste pores, not previously described. They ranged from 5 to 10 for ovoid and 25 to 25 for round papillae. Each circumvallate papilla had an ovoid bulb (with 2–5 taste pores) encircled by an annular groove and two pads (i.e. not described previously). The papillary system's regional divergence was specialized for their harsh and semi‐harsh diet.

Scanning electron microscopic characterizations of the tongue of the Nubian goat (Capra aegagrus hircus): A specialized focus on its papillary system adaptation to Egyptian environmental conditions

“…These morphological adaptations to the Nubian goats grazing habits are compatible with the main characteristics of several taxonomic groups. Our results revealed that the ventral surface of the apex was classified into the smaller rostral papillary region on the tip and the larger non‐papillary region by the U‐line of the filiform papillae, similar to that reported in Egyptian Ossimi sheep (Abumandour et al, 2022b). Meanwhile, similar results were reported in the Egyptian water buffalo, but the projected U‐line separating the papillary and non‐papillary regions consisted of projected fungiform papillae (El‐Bakary & Abumandour, 2017).…”

“…Considering that the tongue of ruminants is an organ well‐matched to the processes of chewing and ruminating food, morphology with lingual prominence and distribution of lingual papillae appear to be traditional characteristics in both primary feeding groups, namely grazers and browsers (Shipley, 1999). Previously published data described variability of ruminant anatomical lingual lineaments as an evolution key for understanding feeding strategies based on the type of available food particles, ecological conditions and the feeding mechanism appropriate to each species (Abumandour et al, 2022b; El‐Bakary & Abumandour, 2017; Kurtul & Atalgin, 2008). Feeding behaviour observations in Nubian goats show that they feed primarily on dried grasses and herbs and may browse on the leaves of trees and bushes.…”

“…Five Nubian goat ( Capra aegagrus hircus ) tongues were used in the SEM technique (Abumandour et al, 2022b). The collected lingual samples were fixed at 4°C in a solution of fixation formed from; 2% formaldehyde, 1.25% glutaraldehyde in 0.1 M sodium cacodylate buffer, pH 7.2.…”

“…sheep (Abumandour, Morsy, & Elghoul, 2022), cattle-yak (Ding et al, 2016) and chital deer (Erdogan & perez, 2013a). In the meantime, the existence of four papillary types, including two mechanical (filiform and conical) and two gustatory (fungiform and circumvallate)…”

“…These adaptations were clear in the shape, direction, distribution and structure of these lingual papillae (Abumandour, 2014). There are numerous previously published morphological articles concerned with the lingual properties and papillae of the different domestic animal species (Abumandour, Morsy, & Elghoul, 2022b; Ding et al, 2016; El‐Bakary & Abumandour, 2017; Kobayashi et al, 2005; Kumar et al, 1998; Kurtul & Atalgin, 2008).…”