Gross Morphology and Morphometry of Foetal and Adult Dromedary Tongues AS Saidu1*, AZ Jaji2, PM Yawulda1, F Da'u3, Y Ahmad4 & N Elelu 2

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Sokoto Journal of Veterinary Sciences, Volume 13 (Number 2). August, 2015 RESEARCH ARTICLE Sokoto Journal of Veterinary Sciences (P-ISSN 1595-093X/ E-ISSN 2315-6201) Saidu et al/Sokoto Journal of Veterinary Sciences (2015) 13(2): 49-53 http://dx.doi.org/10.4314/sokjvs.v13i2.8 Gross morphology and morphometry of foetal and adult dromedary tongues AS Saidu1*, AZ Jaji2, PM Yawulda1, F Da'u3, Y Ahmad4 & N Elelu 2

1. Department of Veterinary Public Health and Preventive Medicine, Ahmadu Bello University, Zaria. Nigeria 2. Department of Veterinary Anatomy, Faculty of Veterinary Medicine, University of Ilorin, Ilorin, Kwara State, Nigeria 3. Kano State Ministry of Animal and Natural Resources 4. Department of Veterinary Anatomy, Faculty of Veterinary Medicine, University of Maiduguri, Nigeria

*Correspondence: Tel.: +2348039359544, E-mail: [email protected] Abstract Gross morphology and morphometry of apparently normal tongues of forty antenatal and ten adult dromedaries (Camelus dromedarius) of both sexes, procured from the Maiduguri Metropolitan abattoir, were studied. This was with the aim of documenting information on these aspects. The thirteen months dromedary gestation period was divided into four quarters for the purpose of the foetal tongue morphometric study, with ten foetuses per quarter. The prenatal and postnatal tongues were grossly observed to be flat apically and oval basally. They were highly flexible, like other ruminants’ tongues, and relatively small to the overall sizes of the study animals. The highest lingual weight percentage of the body weight of 0.39% was attained at the second prenatal growth phase of the dromedary while the least, 0.16%, was attained in the adult. The foetal tongues showed levels of significant increases in sizes and weights throughout the prenatal growth phases. It was concluded that the dromedary tongue is similar to other ruminant tongues and most of the salient gross features, like gustatory and non-gustatory papillae, of the dromedary tongue were already obvious as early as the first prenatal growth phase (2 – 3 months) and the remaining three periods were associated with size increases. In the prenatal dromedary tongues studied, the salient gross features of the tongue were fully evident right from the first quarter of gestation (first three months of prenatal life), but were relatively small in size. Likewise; the mean dimensions and the weights obtained in the present study, showed significant increments across the four-quarters gestation. This is not unrelated with the structural developments of the overall body size and weights.

Keywords: Adult, Dromedary, Foetus, Morphometry, Tongue Received: 14-04- 2015 Accepted: 03-08-2015

Introduction Camels belong to the taxonomic order Artiodactyla Rollefson et al., 1991; Peters, 1997; Pastoret, (even toed Ungulates), sub-order Tylopoda (Pad- 1998). About 70% of the world’s camels are found footed), of the Camelidae Family. The Camelidae is within the tropics and over 90% of the African a relatively small family of two genera: Camelus herds are present in the region. African population (Old world camels) and Lama (New world camels). is thought to be increasing slightly, especially The genus Camelus consists of Camelus within the tropics. As for some other areas, dromedarius, commonly known as the dromedary, however, numbers are actually declining, since the one-humped or Arabian camels and Camelus camel is being replaced by other domestic species bactrianus, the Bactrian or two-humped camels (sheep, cattle and goat) (FAO, 1994). The (Burton et al., 1969; Burton, 1972; Wilson, 1984). dromedaries account for about 95 % of the world’s Domestication of dromedaries first started in 19.4 million camels, 15 million of which are found central or southern Arabia. However, they became in Africa (FAO, 2003). extinct in the wild about 2,000 later (Kohler-

Sokoto Journal of Veterinary Sciences, Volume 13 (Number 2). August, 2015

Dromedaries are well known in literatures for their the apex. The lingual body breadth (rostral lingual unique features and milk, meat, wool, hair and breadth) was the widest distance between the two hide products; serve for riding, and as draft lateral limits of the lingual body. The lingual basal animals for agriculture and short- breadth (caudal lingual breadth) was the widest distance transport (Schwartz & Dioli, 1992; Al- distance between the two lateral limits of the Busadah, 1998). lingual base, including the height, of the Torus The tongue is a muscular organ with strong and linguae. definite movements. It has free parts (apex and body) and an attached part (the root). It is an Data analysis important organ in the animal’s body. It is a The differences between the above dimensions renowned organ of taste owing to its component across the developmental stages of the foetal taste buds, it plays unique role in prehension, dromedaries were tested using the ANOVA from lapping, grooming and manipulation of food in the the computer statistical software, Graph pad ® mouth (Igado, 2011). The dromedary belongs to Instat , version 3.06, 32 bits for Windows. The the arid lands, where xerophytes with hard rough whole variables were recorded in a mean± SD of thorny stems grow. The dromedary has thus measurement of errors. Values of p< 0.001 to developed special adaptive feature of sturdy p<0.05 were considered significant throughout the rubbery mouth to enable it maintain efficient measurements of the study. feeding on these plants without damage from their thorns and stems (Sui et al., 1983). Results There is scanty information on the morphological In the foetal and adult dromedaries studied, the features of the tongues of foetal (Salehi et al., tongue was pale grey in colour and flat (apically) to 2010) and adult dromedaries (Qayyum et al., 1988; oval (basally) in shape (Plate I). The apex and body Erdunchaolu et al., 2001; Peng et al., 2008). This of the tongue were freely movable while the Base study aims at documenting information on the was relatively stable and made up of the Torus morphometry of the foetal and adult dromedary linguae and the root of the tongue. At the first tongues with special emphasis on the four growth phase, a foetus measured 44.00 ± 9.72 cm prenatal developmental stages of the dromedary in crown-rump length (CRL), 3.42 ± 1.36Kg in body (Jaji et al., 2011). Such information will be quite weight and its tongue measured 8.33 ± 1.99cm in valuable in providing baseline data for academics, length, 1.85 ± 0.56cm and 2.72 ± 0.60cm in livestock practitioners and scientists towards respective body and basal breadths, and 9.92± improving veterinary education, research and 4.61g in weight, 0.31% of the bodyweight (Table animal health. 1). These dimensions and weights showed extremely significant increases along the four Materials and methods dromedary growth periods except the basal lingual This study was conducted at the Maiduguri breadth that showed no significant increase in size Metropolitan abattoir, Nigeria. Forty foetuses, ten at the first growth period (Table 1).The adult per stage, and ten adult dromedary tongues from dromedary tongue (of both sexes) was very mobile both sexes and above 5 years were used in this (flexible) and furnished with lots of filiform study. The animals were apparently normal. The papillae spanning the dorsum of its apex and body weight (kg) and crown-rump length (cm) of body. It was also showed that, in all the stages of foetuses associated with quarters of gestation development, the camel tongues were elongated, were measured using citizen® electronic weighing with flat surfaces and rounded apically. balance (0.1g – 100Kg precision) and Butterfly® There were many Lentiform and conical papillae measuring tape (0.1 – 150cm precision), on the dorsum of the Torus linguae. A conspicuous respectively. The data thereby obtained and column of five circumvallate papillae was found at correlated with developmental horizons, enabled each lateral margin of the Torus linguae in the the placement of the foetuses into broadly based adult male tongue (Plate II). In addition, the groups as adopted from Jaji et al. (2011). tongue was observed to be smaller in relation to Immediately after slaughter, the foetal and adult the overall size of the animal. The animal weighed tongues and their associated structures were 546.56 ± 52.22 Kg in body weight, while the dissected out from the animals. The weights of the tongue weighed 0.72 ± 0.17 Kg, making about tongues were measured in grams, using 0.16% of the animal weight. The tongue measured Citizen®electronic weighing balance and their 41.33 ± 2.25cm in length, 6.50 ± 0.63cm and 20.00 lengths (cm) and breadths (cm) were also ± 4.70cm in respective body and basal breadths measured using the butterfly® measuring tape. (Table 1). There were no statistically significant The lingual length was the distance from the root differences observed between sexes in this study. of the tongue, nearest to the pharynx, to the tip of

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Plate I: Photograph of the dorsum of the second Plate II: Magnified photograph, a closer look at the trimester, 3-6 months gestation female dorsum of the basal part of the male tongue depicting dromedary tongue showing its three major its rounded part (Torus linguae, TL) and root (R) components components Legend: A; apex, Bo; Body and Ba; Base Legend: C; Conical papillae, CV; Circumvallate papillae, L; Lentiform papillae, R; Root, TL; papillae of the Torus linguae. There is a row of five CV papillae on either side

Table 1: Mean ± S.D Values of Body and Tongue Morphometry in the Foetal and Adult Dromedary Prenatal phase Adult

Q1 (2-4 Q2 (5–7 Q3 (8-10 Q4 (11-13 dromedary Measurements Months) Months) Months) Months) >5years

Crown-rump length (cm) 44.00 9.72 67.00 ±7.35 *** 85.00 ± 4.04*** 100.67±4.89*** - Body weight (Kg) 3.42 ± 1.36 8.02±2.17*** 12.50 ±1.92*** 17.50±3.51*** 540.56± 52.22 Lingual Weight (g) 9.92 ± 4.61 28.83 ±10.26*** 44.83 8.84*** 54.82 4.02*** 720 ± 170 Relative percentage - Lingual 0.31 0.39 0.38 0.28 0.16 to body weights (%) Lingual Length (cm) 8. 33 ± 1.99 11.33±1.66*** 13.25±1.67*** 13.92±0.58*** 41.33±2.25 Lingual body breadth (cm) 1.85 ± 0.56 1.77 ± 0.26*** 2.25±0.60*** 2.92±0.38*** 6.50±0.65 Lingual basal breadth (cm) 2.72 ± 0.60 3.00 ± 0.55 ns 4.30 ± 0.68*** 4.50 ± 0.45*** 20.00 ± 4.70 ns - Not significant * - Significant (P<0.05) ** - Significant (P<0.005) *** - Significant (P<0.001)

Discussion pseudoruminant, its tongue showed resemblance Grossly, it was obdered that, in all the stages of to those of ruminants; its tongue showed high development, the camel tongues were elongated, degree of flexibility and its Torus linguae was well with flat surfaces and rounded apically. This was in furnished with five large diameter agreement with the observations of Bello et al, circumvallate papillae along its entire surface (2014). According to Doran (1975), the camel typical of ruminants (Frandson et al., 2009). tongue belongs to the type I (intra-oral) tongue in Different morphological structures of the tongues domestic animals. The size of the adult dromedary of ruminants including the pseudoruminant, tongue was observed to be relatively smaller than camels, are specialized to fulfil different its whole body size, in agreement with Wilson anatomical and physiological functions, such as (1984). Although the dromedary is a swallowing, water uptake, prehension, grooming,

Sokoto Journal of Veterinary Sciences, Volume 13 (Number 2). August, 2015 suckling, vocal modulation and even adaptations of the tongue. The hyoglossus muscle was a wide to some environmental conditions (Kilinc et al., flat muscle observed at the base of the tongue. It 2010; Mancanares et al., 2012). Moreso, the originated from the basihyoid bone, lingual mammalian tongue is known to exhibit various process and the thyrohyoid bone and inserted at morphological adaptations in different species. the root of the tongue; and laid medial to the The distribution of the different types of papillae styloglossus. The genioglossus attached to the on the surfaces of the tongue plays a vital role in symphysis and adjacent body part of the mandible. taxonomic ranking; to the extent of differentiating It inserts in the tongue, in agreement with Chibuzo one genus characteristics from the other or even (2006). among different species (Pastor et al., 2011). For In the prenatal dromedary tongues studied, the instance, one humped camels are adapted to salient gross features of the tongue were fully desert environment and to feeding on the thorny evident right from the first quarter of gestation structures around. Therefore, morphological (first three months of prenatal life), but differences and variations appearing in the tongue were relatively small in size. Likewise, the mean are directly associated with dietary specializations dimensions and the weights obtained in the and feed types, as well as various environmental present study showed significant increments conditions (Iwasaki, 2002). The dromedary has across the four-quarters gestation. This is not thus developed special adaptive feature of sturdy unrelated to the structural developments of the rubbery mouth to enable it maintain efficient overall body size and weights. The figures for the feeding on these plants without damage from their overall body weight and CRL showed slight thorns and stems (Sui et al., 1983). differences with earlier reports (Musa & The dromedary tongue in this study was observed Abusineina, 1978; Ribadu, 1988; Jaji et al., 2011). to consist of a mass of muscle covered by mucous It was concluded that the salient gross features of membrane. The muscles comprises of extrinsic the dromedary tongue were fully evident right parts which were paired and entered the tongue from the first quarter of gestation but were from the sides, and the intrinsic muscles within the relatively small in size. The tongue of the prenatal tongue, which is in agreement with Chibuzo and adult dromedary, just like those of other (2006). The ruminant digestive system uniquely ruminants are highly flexible organs and their sizes qualifies ruminant animals such as cattle to make are relatively small when compared to the overall efficient use of high roughage feedstuffs such as sizes of the animals. We therefore recommended forages. Anatomy of the ruminant digestive system that, histological studies need to be undertaken to includes the mouth, tongue, salivary glands, determine the timing for the appearance of taste oesophagus, and the four-compartment stomach buds in the gustatory papillae of the foetal (rumen, reticulum, omasum, and abomasum), dromedary tongue. pancreas, gall bladder, small and large intestines (Parish, 2011). This also resembles that of Acknowledgement dromedary camel and it agreed with the The authors are indebted to the staff of Faculty of observation of Bello et al. (2012). These extrinsic Veterinary Medicine, University of Maiduguri, and muscles comprised of the styloglossus, which was Maiduguri Metropolitan abattoir, Borno State observed as a long slender muscle on the Nigeria, for their assistance during the course of ventrolateral surface of the tongue. It originated this research. from the styloid bone and inserted at the middle

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