ABSTRACT
Information on the anatomical studies of the endocrine glands of the indigenous one-humped camel in Northern Nigeria is scarce, and the fact that these endocrine glands may be involved in the mechanisms of adaptation to hostile environment through which it survives for long periods without food and water in the arid zones. Thirty (30) one-humped camels, comprising fifteen (15) males and fifteen (15) females were used in this study. The animals were divided into 3 groups of 10 animals each. Group A, B and C constitute 10 one-humped camels (5 males and 5 females) aged between 1 to 5 years, 6 to 10 years and above 10 years, respectively. The gross anatomical study of the endocrine glands namely; thyroid, parathyroid and adrenal glands were done to determine their shapes, texture, color, surfaces, and borders, measurements on the weights where obtained using digital weighing balance, and measurements of width, thickness and length were taken using digital vernier caliper. Histological features were studied using routine Haematoxylin and Eosin (H and E) for light microscopy. Histochemical features of the endocrine glands were explored using Periodic Acid Schiff (PAS) special stain; for thyroid and parathyroid glands, Acid Hydrolysis Azure A for thyroid gland, Alcian blue and potassium dichromate for adrenal gland. Hormonal assays of Thyroid Stimulating Hormone (TSH), Triiodothyronine (T3), and Tetraiodothyronine (T4) were studied using three different Enzyme Linked Immuno Servent Assay (ELISA) Kits (obtained from Nazo Medical Diagnostic Services, Lagos) for the T3, T4, and TSH ELISA. The result showed that the thyroid gland was a paired-lobe, and lengthy organ, with blood supply from superior thyroid, middle thyroid and inferior thyroid arteries. Correlation of the weight of the thyroid gland in one-humped camel was directly proportional to the age of the animal, while the correlation of the concentration of the thyroid hormones (T3 and T4) was inversely proportional to the weight and the age of the
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thyroid gland in the indigenous one-humped camel. There were higher concentrations of thyroid hormones in the young than in the adult. Histological studies revealed the appearances of numerous vacuolated colloids, and apoptosis of the follicular cells of the adult animals, which highlight the reason for the above correlations. There were follicular and parafollicular cells. The parathyroid glands were two pairs of glands situated around thyroid gland lobes. In addition, accessory parathyroid glands were seen, in this study, situated on the right, while some on the left of the indigenous one-humped camel. The result showed that there was sexual dimorphism in the weight, length, width and thickness in the parathyroid glands in the juvenile age group and the young adult group, especially in the width, which was highly significant (P<0.01). The general histological features of the parathyroid gland consisted of densely packed chief cells (light and dark cells), oxyphil cells, and abundance of adipose cells in the adult male and female, but the adipose cells were absent in the young group. The right adrenal gland was positioned superior medial to the right kidney attached to the inferior medial surface of the liver, while the left adrenal gland was superior medially positioned within fat from the left kidney. There was sexual dimorphism in the weight and thickness of the adrenal gland of the female in the juvenile age group. Histologically, the adrenal cortex comprised of three zones generally, but four zones were seen in the young adult groups named; Zona glomerulosa, zona fasciculate, zona intermedia, and zona reticularis. Chromaffin cells of the medulla were identified by potassium dichromate chromaffin reactions. The results showed age and morphometric correlations, sexual dimorphisms and cellular morphology of the endocrine were pertinent to enhance the understanding of how the animal adapts to its environment, as this will provide baseline information for future related researches.
TABLE OF CONTENTS
1. Cover page………….………………………………………………………….….I
2. Title page………….………………………………………………………….….II
3. Declaration ……………….……………………………………………..………III
4. Certification ………………………..……………………………………..…….IV
5. Acknowledgments…………………………..………………………………..….V
6. Abstract………………………………………………….……………………VI-VII
7. Table of contents …………………………………………………………….VIII – X
8. List of figures………………………………………………………………..… XI
9. List of tables……………………………………………………..………….…..XII
10. List of plates………………………………………………………………XIII-XVII
11. Abbreviations ………………………………………………………………….XVIII
12. Chapter One: Introduction ………….…………………………………………1
1.1 Background ..……………………………………………….1 1.2 Statement of Research Problem…..…….………………….2 1.3 Justification for the Study………………………………….3 1.4 Significance of the study….………………………………..3 1.5 Aim of the Study ………….………………………………..3 1.6 Objectives of the Study……..…………………………………3
13. Chapter Two: Literature Review………………..……………………………………5
2.1 Dromedary camel ………………..………………….……….5 2.1.1 Etymology of the dromedary camel ..………………………5
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2.1.2 Evolution and Distribution of camel…………………………………5 2.1.3 Lifespan and Reproduction…………………………………………..7 2.1.4 Domestication of Camel………………………….……..………7 2.1.5 Relationship with Humans………………………………………8 2.1.6 Population and Geographic range/ Habitat…………………………..8 2.1.7 Gross Anatomy and Characteristics of the Dromedary Camel…11 2.2.0 Endocrine Glands …………………………………………………….12 2.2.1 Gross organization of mammalian thyroid gland……………….13 2.2.2 Histological organizational of mammalian thyroid gland………16 2.2.3 Hormones of the Thyroid Gland…………………….………….18 2.3 Gross and Histology of mammalian parathyroid gland. …………19 2.4 Gross and Histology of mammalian adrenal gland…….…………22
14. Chapter Three: Materials and Methods………..……………….……….………….28
3.1 Experimental Animals ………………………………….………..29 3.2 Study Design …………………………………………….……….30 3.3 Hormonal Assays ………………………………………………… 30 3.4 Dissection of the Endocrine glands……………………….…….33 3.5 Gross Anatomical Studies ………………………………………40 3.6 Histological Studies ……………………………………………42 3.7 Histochemical Studies …………………………………………43 3.8 Statistical Analysis ……………………………………….…….44
15. Chapter Four: Results…………………………………..……….……………….45
4.1 Thyroid gland …………………………………………………….45 4.1.1 Gross Anatomical Studies of the Thyroid.……………………45
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4.1.2 Morphometric Studies of the Thyroid ………………….………..49 4.1.3 Hormonal Assay…………………………………………………….50 4.1.4 Histological and Histochemical Studies of the Thyroid ………..61 4.2 Parathyroid Gland ………………………………………………… 80 4.2.1 Gross and Morphological Studies of the Parathyroid …..……… 80 4.2.2 Morphometric Studies of the Parathyroid………………………. 83 4.2.3 Histological and Histochemical Studies of the Parathyroid……. 89 4.3 Adrenal Glands……………………………………..………………102 4.3.1 Gross and Morphological Studies of the Adrenal Glands.………102 4.3.2 Morphometry of the Adrenal glands…………………………….104 4.3.3 Histogical and Histochemical studies of the Adrenal Glands…..106
16. Chapter Five: Discussion ……………………………………………………….. 132
17. Chapter Six: Summary, Conclusion and Recommendation……………………… 142
6.1 Summary……………………………………………………………………142
6.2 Conclusion ..………………………………….…………………………………… 144 6.3 Recommendations …..…………………………….……………………… 145
18. References ……………………………………………….……….………. 146-151
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CHAPTER ONE
INTRODUCTION 1.1 Background Dromedary camel (Camelus dromedarius) as a livestock species is gaining economic interest because of its adaptation to harsh climatic conditions and resistance to diseases Bengoumi (1992), Faye (1997), and Faye and Bengoumi (2000). Such adaptation is the basis for the reputation of this specie to be uniquely able, among other large mammals, to survive under harsh desert conditions. One of the dromedary‟s mechanisms of adaptation to its natural habitat is changes in the activity of its endocrine glands, such as the thyroid gland, parathyroid gland, adrenal gland, pituitary gland and others, which are implicated in growth and development, complex series of metabolic functions, thermoregulatory, specific organ functions, among many, yet numerous morphological variations of these glands are not well explored (Rejeb et. al., 2011). Dromedary Camel is a specie of animal that is anatomically and physiologically adapted to water and food restrictions and to an excessively hot climate (Ouajd and Kamel, 2009). It can survive in an incredibly harsh environment (up to 70°C), that is lethal to all other species of animal (Ouajd and Kamel, 2009). Camel can store water in all its body compartments (intracellular, extracellular, blood, and especially GIT). Every organ has the extraordinary capacity to store water Karkar (2011). Similarly, it is well known for its feats of endurance, a 750kg camel can carry 450kg luggage and able to travel at 16km/h for up to 18 hours nonstop Snow (1992).
Dromedary camel is described as the „ship of the desert‟, as its toes have adapted to walking on sand without sinking, carrying heavy loads and transport them across the deserts Snow
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(1992). Even though the traditional usages of camel in most countries have been supplanted by motorized transport, however, its cultural and economic importance have been maintained by camel racing, durbar racing, military mascots (such as the Nigerian Corporal Camel Rakumi in 65 division of 81 Battalion of the Nigerian Army in Lagos ANON (2011), meat and milk provisions, hair and leather textiles, transportation, working animals in farms Yagil (1982) and Snow (1992). The breeds of the one-humped camel found in Northern Nigeria as indigenous are “Ja” (dark brown), “Fari” (grey white), “Bula” (pied colored), and “Bakin-biri” (Brown Black), identified based on their phenotypic trait of color (Abdussamad et. al., 2011). This needs further investigation because these ecotypes could be of the same breed or of different breeds, the genuineness of which could only be proven by molecular genetic studies, and is yet to be done. The local name of camel in Hausa Language is called “Rakumi”. A matured female is called “Taguwa”, while the matured male is called “Amale” (Abdussamad et. al., 2011). 1.2 STATEMENT OF RESEARCH PROBLEM: There is paucity of information on the anatomical studies of the endocrine glands of the indigenous one-humped camel, despite the fact that these endocrine glands are involved in the Dromedary‟s mechanisms of adaptation to hostile environment through which it survives for long periods without food and water.
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1.3 JUSTIFICATION FOR THE STUDY The studies on the endocrine glands of the indigenous one-humped camel is pertinent to enhance the understanding of how the animal adapts to its environment, as this will provide baseline information on the camel for future related researches. 1.4 SIGNIFICANCE OF THE STUDY The significance of the present study were: It could be useful in comparative anatomy and evolutionary studies with other species of the artiodactyla order and higher orders like humans. It could also enhance and provide basic and clinical investigative information in endocrinology and related research fields, such as Animal breeding and Biotechnology. 1.5 AIM OF THE STUDY The aim of the work was to study the anatomical features of thyroid, parathyroid and adrenal glands of the one-humped camel indigenous to Northern Nigeria 1.6 OBJECTIVES OF THE STUDY The objectives of the research were:
I. To study the gross morphology and morphometry of the thyroid, parathyroid and adrenal glands of the one-humped camel.
II. To study the histology of the thyroid, parathyroid and adrenal glands of the one-humped camel using routine stain (H & E).
III. To study the histochemistry of the thyroid glands using Periodic Acid Schiff (PAS) for demonstration of glycogen and Azure A Acid hydrolysis technique for
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demonstration of parafollicular cells; study the histochemistry of parathyroid glands using Periodic Acid Schiff (PAS) for demonstration of glycogen, as well; and to study the adrenal glands of the one-humped camel using Alcian Blue for demonstration of mucin and Potassium dichromate for demonstration of chromaffin cells.
IV. To determine the serum levels of Thyroid Stimulating Hormone (TSH), Triiodothyronine (T3) and Tetraiodothyronine (T4) using ELISA auto-analyzer kits.
V. To determine the sexual dimorphism in the morphometric variables of the thyroid, parathyroid and adrenal glands.
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