Elite Research Journal of Agriculture and Soil Science Vol. 1(1) pp. 5 - 7, March, 2014. Available online http://www.eliteresearchjournals.org/erjass/index.htm Copyright © 2014 Elite Research Journals

THE PRENATAL DEVELOPMENT OF THYROID GLAND IN ONE HUMPED CAMEL (Camelus dromedarius): HISTOMORPHOLOGICAL STUDY

1 A. Bello ;

1J. E. Onu;

1 M. L Sonfada;

2 M.A Umaru;

1S.A. Shehu;

1M.I. Jimoh;

1O. Olusola

1Department of Veterinary Anatomy, Usmanu Danfodiyo University, Sokoto, Nigeria:

2Department of Theriogenology and Animal production, Usmanu Danfodiyo University, Sokoto, Nigeria.

Accepted 25 February, 2014

This study aimed at investigating the prenatal development of the thyroid gland of the one humped camel using standard histomorphometric methods. In the experiment, fifteen foetuses obtained from Sokoto metropolitan abattoir at different gestational ages were used for the study. The fetuses were weighed, grouped and aged. The approximate age of the foetuses was estimated from the crown vertebral rump length (CVRL) and samples were categorised into first, second and third trimester. In all the foetuses the gland was grossly bi-lateral and cylindrical in shaped with smooth external surface. Histologically, the thyroid gland consisted of a connective tissue capsule and trabeculae extending from the capsule into the paranchyma of the gland, which divided it into lobules at variable degree base on gestational ages. Each lobule consisted of two sized follicles in variable numbers, the large and small in second trimester. The large follicles were lined by cuboidal epithelium, while the small follicles were lined by columnar epithelium at third trimester. The follicles had colloid material in their lumen, resembling an apocrine secretion from the lining epithelial cells. The para follicular or C-cells were not seen in the thyroid glands of camel prenatally. Keywords: Camel, Histomorphology, Thyroid gland, Prenatal development.

INTRODUCTION Thyroid gland is an endocrine gland which secretes thyroglobulin, triiodothyronine and thyroxin hormones (Banks, 1993). Thyroxin plays an important role in metabolism of the animal body. Thyroid gland consists of follicles lined by follicular cells. The interfollicular space has been reported to be filled with connective tissue (Abdel-Wahab and Hamza, 1970; Leeson and Leeson, 1970). Thyroid glands have important role in growth and development of fetus during pregnancy and maintaining metabolic homeostasis in mammals (Abdel-Magied et al., 2000).The thyroid gland is the first endocrine gland to appear on the embryonic period (Volumenie et al. 2000; Clara et al., 2004). Its organogenesis begins when the medium endoderm cells start getting thick, forming a diverticulum, in the primitive pharynx floor (Bello et al.,2012). This diverticulum descends, and at the seventh week of pregnancy it stops at cervical spine height. The follicles cells, responsible for hormonal biosynthesis, derive almost completely of the primary thyroid. The differentiations begin when the migration finishes (Clara et al., 2004). Research work on the morphology, physiology, pathology, gross and developmental anatomy of various organs and system (Abdel-Wahab and Hamza, 1970; Cummings et al. 1972; Bustinza, 1979, Asari et al., 1985; Wilson, et al., 1990; Recce, 1997; Osman et al. 1999; Abdel-Magied et al., 2000; Volumenie et al. 2000; Franco, et al., 2004; Sonfada, 2006; Bello et al.,2012; Umaru and Bello, 2012 Hena et al 2012; Bello et al.,2013 ) has been reported in different countries by many researchers on foetal and adult camel, but little of such studies have been conducted on the histological changes of the thyroid gland of the camel fetus. Thus, paucity of information on the prenatal development of camel thyroid gland; hence the present study was undertaken to bridge the information gap.

Corresponding Author E-mail: abccrcfge28@gmail.com Tel: +234(0)8039687589

MATERIALS AND METHOD The study was carried out on 35 foetuses of the one-humped camel collected from the metropolitan abattoir, Sokoto at different gestational ages. The collected foetuses were then taken to the Veterinary Anatomy laboratory of Usmanu Danfodiyo University; where the weight and age of the foetus were determined. The foetal body weight was measured using electrical (digital) weighing balance for the smaller foetuses and compression spring balance (AT-1422), size C-1, sensitivity of 20kg X 50g in Kilogram for the bigger foetuses. The approximate age of the foetuses was estimated by using the following formula adopted by El-wishy (1981). [GA = (CVRL + 23.99)/0.366] [El-Wishy et al. 1981] Where GA (Gestational Age) is in days CVRL (Crown Vertebral Rump Length) is measured as a curved line along the vertebral column from the point of the anterior fontanel or the frontal bone following the vertebral curvature to the base of the tail. Based on this, foetal samples were divided into 3 main groups as adopted by Sonfada, (2008): 1

st trimester = below 130 days

2nd

trimester = 131- 260 days 3

rd trimester = 261 - 390 days

Histological samples of thyroid gland were examined grossly and weight using electrical (digital) weighing balance, size A-1, sensitivity of 0.1g X 0.01g in gram. About 1cm

2 thick of

sample from each group was collected and fixed in 10% formalin solution. After fixation was achieved, the tissue sample was processed for paraffin blocks preparation. The sections of 5-6µm were subjected to haematoxylin and eosin for routine morphology (Bancroft and Stevens, 1990). The standard sections were examined under light microscope and micrographs taken using motic camera with 5.0 mega pixel.

RESULTS AND DISCUSSION Although, thyroid gland is the first endocrine gland to appear on the embryonic period, many forms of the thyroid gland can be found in different domestic animals fetuses during early development (Volumenie et al. 2000; Fang et al., 1999), a similar type of growth to the one found in this research. In camels, the thyroid gland in the body was within the first ring of trachea, consisting of two lobes on both side and an isthmus connecting these lobes which became prominent with advancement of gestation. This is similar to other reported large animals like cattle (Miyandad, 1973) and buffaloes (Getty et al., 1986). The gland appeared reddish brown in colour which is in concordance with the findings of Schwartz and Dioli (1992).

Fig. 1: Photomicrograph of Camel thyroid gland at 1st

Trimester showing zones of connective tissue (green arrow), immature tissue, no organization follicular and colloid observed. H&E 200x

Fig. 2: Photomicrograph of Camel thyroid gland at 2nd

Trimester showing cellular differentiation most incomplete, with partial mature follicular organization (A), with few complete follicles composing of small number of cells (Red arrow) and no colloid observed. H&E 200×

Fig. 3: Photomicrograph of Camel thyroid gland at 3rd

Trimester showing complete cellular differentiation and follicular organization, few connective tissue (Green arrow), follicles were spherical (Red arrow), with no colloid (A) and follicular cells were cuboidal in shape (Red arrow). H&E 200x

Histologically, the thyroid gland consisted of a connective tissue capsule composed of undifferentiated collagenous fibers at first trimester, which differentiate into coarse and fine collagenous fibers at second trimester. The presence of Fibroblast and small blood vessels in the capsule marked the third trimester. At third trimester, the trabeculae were seen extending from the capsule into the parenchyma of the gland and dividing it into lobules with each lobule consisted of aggregation of follicles. This finding is in line with that reported previously in bovine (Abdel-Magied et al, 2000; Atoji et al., 1999), Llama (Sukon, 2009) ovine (Fang et al., 1999), caprine (Fang et al., 1999), canine (Getty et al., 1986) and porcine (Volumenie et al. 2000)

At first trimester, there is no formation of follicles in the gland (Fig I), at second trimester the cells begain to be arranged forming colonies of undifferential cells, resembling low columnar to cuboidal in shape. At third trimester, clear large lobules with very few small lobules in the parenchyma are formed. Each lobule consisted of aggregation of follicles. Two types of follicles were identified, large and small at the terminal gestational age (Fig. III). Similar observations have been recorded by Abdel-Magied et al. (2000) and Sukon, (2009) on cattle and Llama respectively. The large follicles were lined by low cuboidal epithelium having flattened nuclei and were assumed to be inactive cells. The small follicles were lined by high cuboidal epithelium with rounded nuclei, these were active cells. Each follicle was filled with a gel-like material called colloid (Fig. III). The colloid is a storage form of follicular epithelial secretion. This finding is in line with that reported by Sukon, (2009) on Llama. Para follicular or C-cells were not present or pronounce.

CONCLUSION

Considering the complex activities taking place in the differentiation of the gland over a long period of time, there is need to study this development weekly using light and electron microscopy in order to conclude this findings.

Bello et al 6

REFERENCES Abdel-Magied, E. M., A. A. Taha and A. B. Abdalla, (2000).

Light and electron microscopic study of the thyroid gland of camel (Camelus dromedarius). Anat. Histol. Embryol., 29(6): 331-336.

Abdel-Wahab, M. F. and A. E. Hamza, (1970). Thyroxin contents in thyroid glands of domestic animals. IV. Thyroid activity of camel, cattle, sheep and goats in Sudan. Endokrinologie, 56: 206-212.

Asari M., Oshige H., Wakui S., Fukaya K., Kano Y., (1985). Histological development of bovine abomasus. Anat. Anz. 159, 1-11.

Atoji, Y., Y.Yamamoto, Y. Suzuki and R. Sayed, (1999). Ultrastructures of the thyroid gland of the one-humped camel (Camelus dromedarius). Anat. Histol. Embryol., 28(1): 23-26.

Bancroft, J. D. and A. Stevens, (1990). Theory and Practice of

Histological Techniques. 3rd

Ed., Churchill Livingston, London, UK.

Banks, W. J., (1993). Applied Veterinary Histology. 3rd

Ed., Mosby-Year Book, Inc. USA. pp: 414-415.

Bello A., Onyeanusi B.I., Sonfada M.L; Adeyanju J.B., Umaru

M.A. (2012). ; A biometric study of the digestive tract of one-humped camel (camelus dromedarius) fetuses, Scientific Journal of Zoology 1(1).Pp 11-16. http://www.sjournals.com/index.php/SJZ/article/view/159>

Bello A., Sonfada M.L., Umar A.A., Umaru M.A., Shehu S.A., Hena S.A., Onu J.E.,Fatima O.O.(2013). Age estimation of camel in Nigeria using rostral dentition: Scientific Journal of Animal Science 2(1) 9-14

Bustinza, A.V. (1979). South American Camelids. In: IFS Symposium Camels. Sudan. Pp 73–108.

Clara, M., Adam, H.; Czihak, G. (1967). Entwicklungsgeschichte des Menschen, 6th ed. Heidelberg: Quelle & Meyer.

DeNardi, F. G. & Riddell, R. H.(1991). The normal esophagus. Am. J. Surg. Pathol., 15:296-309.

El-Wishy, A.B, Hemeida, A B., Omer, M.A., Mubarak, A.M. and El-Syaed, M.A.(1981). Functional changes in the pregnant camel with special reference to fetal growth. British. Veterinary Journal. 137, 527-537.

Fang, J; Schoen, EJ., Clapp, W., To, TT. and Filreman, BH.( 2004). The key role of newborn thyroid scintigraphy with isotopic iodide (123I) in defining and managing congenital hypothyroidism. Pediatrics, , vol. 114, n. 6, p. 683-688.

Franco A, Masot A.J, Gómez L, Redondo E. (2004a) Morphometric and immuno histochemical study of the rumen of red deer during prenatal development. Journal of Anatomy; 204:501–513

Getty, R., S. Sission and J. D. Grossman, (1986). The

Anatomy of Domestic Animals. 5th

Ed., W. B. Saunders Company. Philadelphia, USA.

Hena S.A, Sonfada M.L., Onyeanusi B.I., Kene R.O.C, Bello

A. (2012); Radiographic studies of developing calvaria at prenatal stages in one-humped camel

. Sokoto Journal of

Veterinary Sciences. 10(1): Pp13-16. http://dx.doi.org/10.4314/sokjvs.v10i1.3

Jamdar, M. N. & Ema, A. N, (1982). The submucosal glands

and the orientation of the musculature in the oesophagus of the camel. J. Anat., 135:165-71.

Leeson, T. S. and C. R. Leeson, (1970). Histology, 2nd

Ed., W. B. Saunders Company, Philadelphia, USA.

Luiz C. J. and Jose C. 2005: Basic Histology Text and Atlas 11

th ed. McGraw-Hill

Malie, M. Smuts S. and Bezuidenhout A. J. (1987).: Anatomy of the dromedarius camel. Clarenden press, Oxford, Pp 101-140.

Miyandad, P., (1973). Anatomical studies of the thyroid gland of buffalo. MSc Thesis. Univ. Agri., Faisalabad, Pakistan.

Reece, W. O. 1997. Physiology of domestic animals. Williams and Wilkins. CH. 11, pp. 334.

Schummer, A.; Nickel, R. & Sack, W. O.1979. The alimentary canal. In: The Viscera of Domestic Mammals. New York, Springer-Verlag, Pp 99-202.

Schwartz, H. J. and M. Dioli, (1992). The one-humped camel in Eastern Africa. A pictorial guide to diseases, health care and management. Schonwald Druck. Berlin. F.R. Germany, pp: 228-229.

Smith, J. A.(1989). Noninfectious, metabolic, toxic and neoplastic diseases of Camelids. In: The Vet. Cl. Of N. Amer., Food Animal Practice, Llama Medicine. Johnson, L. W. (Ed.). Phildelphia,W.B. Saunders Co.Pp.103-4.

Sonfada, M.L., (2008): Age related changes in musculoskeletal Tissues of one-humped camel (Camelus dromedarius) from foetal period to two years old. A Ph.D Thesis, Department of Veterinary Anatomy, Faculty of Veterinary Medicine, Usmanu Danfodiyo University, Sokoto, Nigeria.

Sukon, P.(2009). The Physiology and Anatomy of the Digestive tract of Normal Llamas. PhD Thesis, Oregon State University, Corvallis.

Turner, C. D., 1966. General Endocrinology, 4th

Ed., W. B. Saunders Company, London, UK.

Umaru, M.A, Bello, A. (2012.). A study of the biometric of the reproductive tract of the one-humped camel (Camelus dromedarius) in orthern Nigeria.. Scientific Journal of Zoology, North America, Available at: <http://www.sjournals.com/index.php/SJZ/article/view/395>. Date accessed: 26 Feb. 2013.

Volumenie, JL., Polak, M., Guibourdench, J., Oury, JF., Voillard, E., Reyal, F., Raccah-Tebeka, B., Boissinot, C., Madec, FM., Orgiazzi, J., Toubert, ME., Leger, J., Blot, P. and Luton, D. Management of fetal thyroid goiters: report of 11 cases in a single perinatal unit. Prenatal Diagnosis, 2000, vol. 20, p. 799-806.

Watrous, B. J.; Pearson, E. G.; Smith, B. B.; Snyder, S. P.; Blythe, L. L.; Riebold, T. W. & Hedstrom, O. R.,1995. Megaesophagus in 15 llamas: a retrospective study (1985-1993). J.Vet. Internal Med., 9:92-9.

Wilson R.T ,1995: Studies on the livestock of Southern Darfur. Sudan V. Notes on camels. Tropical Animal Health Production, 10:19-25.

Yagil, R., Z. Etzion and J. Ganani, (1978). Camel thyroid metabolism: effect of season and dehydration. J. Appl. Physiol., 45(4): 540-544.

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