Spermatogenesis in the camel (Camelus dromedarius)

Spermatogenesis was studied with the aid of the light and electron microscopes in fourteen sexually mature camels slaughtered at different times of the year. The testes were fixed by vascular perfusion with glutaraldehyde. Spermatogenesis in the camel was generally similar to that of most mammalian species, although some features specific for the camel were observed. Spermatogenesis was found to be continuous throughout the year.     

Forestomach motility in the camel (Camelus dromedarius)

There is a cyclical pattern of motility in compartments 1 and 2 of the forestomach of the camel which can be categorized into A- and B-contractions. An average motility cycle is composed of 7 A- and 5 B-contractions and lasts 5 min, including a pause of 2.3 min. The glandular sacs within the caudal sac of compartment 1 contract 1.7 sec earlier than the caudal sac. The proximal part of the canal between compartment 2 and 3 contracts 1.2 sec prior to the distal part. Forestomach motility is stimulated by distention of the cranial sac of compartment 1 and inhibited by distention of the tubiform portion of compartment 3.     

The locomotion of the camel (Camelus dromedarius)

The feet and gaits of many camels Camelus dromedarius were studied and filmed in Mauritania, Africa. The camel has a digitigrade stance, large feet to support the animal in soft sand, and soles of flexible pads that step readily onto small stones where necessary. The walking stride is long and slow, with the body supported for much of each stride on the two right or two left legs. The pattern of supporting legs was significantly different in slow compared to fast walking camels, and in young compared to adult camels and compared to adults pulling water at the wells. There was no difference in pattern in one individual's walk, when it was either loaded or unloaded. The angles that the leg bones made with each other and with the horizon are depicted for the walk and the pace. The camel is the only animal which paces often and never trots. The pace is an unstable gait only suitable for flat terrain such as that in deserts. It may have evolved from the pace-like walk which is by far the dominant gait in this animal, which spends most of each day walking from plant to plant browsing or grazing. The pace is not used by all camelids, as one author has claimed. The pace and the gallop were only used by the camels at wells, when the animals were chased from the water by men.     

Fatty acid composition of hump triglycerides of the camel Camelus dromedarius.

1. Hump lipids of Camelus dromedarius (single-humped camel) were extracted and fractionated by thin-layer chromatography. 2. The hump lipids were found to be mainly triglycerides with a trace of phospholipids. 3. The fatty acid methyl esters of the triglycerides were studied by gas-liquid chromatography. 4. The major fatty acids were found to be palmitate (35%), stearate (26%), oleate (24%) and myristate (12%). Hexadecenoic (2%) and pentadecanoic acids were minor components.     

Control of luteolysis in the one-humped camel (Camelus dromedarius)

Blood plasma concentrations of 13,14-dihydro-15-keto PGF2 alpha (PGFM) were measured in groups of mature non-pregnant and pregnant camels to study PGF2 alpha release patterns around the time of luteolysis and the timing of the signal for pregnancy recognition. Injection of each of four camels with 10 and 50 mg of PGF2 alpha showed clearly that five times the dose of exogenous hormone produced five times the amount of PGFM in peripheral plasma, thereby indicating that, as in other animal species, PGFM is the principal metabolite of PGF2 alpha in the camel. Serial sampling of three non-pregnant camels on each of days 8, 10 and 12, and three pregnant camels on day 10, after ovulation for 8 h showed a significant (P < 0.05) rise in mean plasma PGFM concentrations only on day 10 in the non-pregnant, but not the pregnant, animals. A single intravenous injection of 20, 50 or 100 iu oxytocin given to three groups of three non-pregnant camels on day 10 after ovulation did not increase their basal serum PGFM concentrations. However, daily treatment of six non-pregnant camels between days 6 and 15 (n = 3) or 20 (n = 3) after ovulation with 1-2 g of the prostaglandin synthetase inhibitor, meclofenamic acid, inhibited PGF2 alpha release and thereby resulted in continued progesterone secretion throughout the period of meclofenamic acid administration. These results showed that, as in other large domestic animal species, release of PGF2 alpha from, presumably, the endometrium controls luteolysis in the dromedary camel. Furthermore, reduction in the amount of PGF2 alpha released is associated with luteal maintenance and the embryonic signal for maternal recognition of pregnancy must be transmitted before day 10 after ovulation if luteostasis is to be achieved. However, the results also indicate that, in contrast to ruminants, the release of endometrial PGF2 alpha in the non-pregnant camel may not be controlled by the release of oxytocin.     

Ultrastructure of the nephron of the one-humped camel, Camelus dromedarius

The nephron of the one-humped camel Camelus dromedarius was investigated by light and transmission electron microscopy. Besides the many features common to other mammalian kidneys, the nephron of the camel is unique in having an unusually thick basal lamina underlying the epithelial cells of the nephron, the thickest being found in part of the parietal layer of Bowman's capsule and the thin limb of the loop of Henle. In the latter, the membrane usually appears lamellated and contains numerous tiny vesicles. In other parts of the nephron, the basal lamina usually has a homogenous appearance. The possible significance of the thickening of the basal lamina is discussed in relation to the general high renal efficiency of the camel.     

A comparative study of serum and organ alpha-amylases of the camel (Camelus dromedarius)

The activity of alpha-amylase of the camel serum was found to be remarkably high (2325 U/l as compared with 77 U/l of bovine serum). The results obtained on chloride activation and substrate affinity studies as well as the DEAE-cellulose absorption properties indicate a substantial similarity between serum and tissue amylase(s) of the camel. On the contrary, a marked difference between the camel and the bovine amylases has been evidenced.     

The intratesticular excurrent ducts of the camel (Camelus dromedarius)

The histology and fine structure of the epithelial cells of the intratesticular excurrent ducts were studied in material collected from fourteen adult camels and fixed by perfusion. The intratesticular excurrent ducts consisted of a terminal segment of the seminiferous tubule, a tubulus rectus, and a rete testis. The terminal segment was lined with modified Sertoli cells which formed a plug-like structure in the receptacle. The tubulus rectus was subdivided into the receptacle, the narrow main part, and the wider distal part, and these parts were lined with different types of epithelium. The rete testis occupied an axial mediastinum testis, and the height of its epithelium varied quite considerably. Degenerated spermatozoa were seen engulfed by the epithelial cells of the entire intratesticular duct system. Light cells, lymphocytes, and macrophages were observed. The fine structure of the epithelium of the intratesticular ducts is discussed in relation to its possible functions.     

Levels of glycosylated haemoglobin in the Arabian camel (Camelus dromedarius)

Proportions of glycosylated haemoglobin (Hb) were determined in 10 Arabian camels (Camelus dromedarius) and were compared with normal controls (n = 59) and diabetic patients (n = 47) using the thiobarbituric acid (TBA) method. The level of glycosylated haemoglobin (5.5%) in camels is significantly different from that of normal healthy humans (4.9%) (P less than 0.001). Whereas the glucose levels were comparable, this difference in percentages of glycosylated haemoglobin may be explained by the difference in survival time between human and camel red blood cells.     

Fine structure of epididymal spermatozoa in the camel (Camelus dromedarius)

The epididymides from five sexually mature camels were fixed by vascular perfusion with glutaraldehyde, and the spermatozoa from four different regions were studied. The fine structure of the camel spermatozoon is similar to that of related species such as bulls and boars. It is relatively short and has a short middle piece. The main morphological changes during epididymal transit are confined to the acrosome and to the position and structure of the cytoplasmic droplet.     

A review of reproduction in the female camel (Camelus dromedarius)

The Arabian camel (Camelus dromedarius), the one-humped camel, is a primary inhabitant of the northern half of Africa, the Middle East and Pakistan and India. The dromedary is a multipurpose animal used for transportation, the production of milk and meat, as well as such by-products as wool, hair and hides. Dromedaries are extremely well adapted to their hot, arid environment. Consequently, Arabian camels are of considerable economic importance. Relatively little attention has been paid to the breeding of dromedaries. In the literature, particularly that in the English language, information on reproduction in the dromedary tends to be fragmentary. This review consolidates several widely scattered reports as projected against the author's own experience. It is hoped that the information is of particular help for those in charge of the breeding of dromedaries in zoological gardens and animal parks in countries where the one-humped camel is a rare species.     

Carbohydrases in camel (Camelus dromedarius) pancreas. Purification and characterization of glucoamylase

The present study analyzed the existence of carbohydrases in camel pancreas compared to some other ruminants. Disaccharidases (maltase, cellobiase, lactase, trehalase and sucrase), glucoamylase and alpha-amylase were detected in pancreas of camel, sheep, cow and buffalo. Enzyme levels in sheep were lower than in the other ruminants. The highest level was detected for alpha-amylase (EC 3.2.1.2). Moderate activity levels were detected for glucoamylase (EC 3.2.1.3) and maltase (EC 3.2.1.20), while other disaccharidases showed very low activity. The results suggested that, in addition to alpha-amylase, glucoamylase and maltase may be synthesized and secreted from pancreas to the small intestine in ruminants. Camel pancreatic glucoamylase was purified and characterized. The purification procedure included glycogen precipitation and chromatography on DEAE-Sepharose and Sepharose 6B. The molecular mass was 58 kDa for native and denatured enzyme using gel filtration and SDS-PAGE, respectively. The enzyme had a pH optimum at 5.5 and a Km of 10 mg starch/mL with more affinity toward potato soluble starch than the other carbohydrates. Glucoamylase had a temperature optimum at 50 degrees C with heat stability up to 30 degrees C. The effect of different cations and inhibitors was examined. The camel pancreatic glucoamylase may possess an essential thiol.     

Fine structure of sertoli cells in the camel (Camelus dromedarius)

The testes of fourteen sexually mature camels were fixed by perfusion with glutaraldehyde. The fine structure of Sertoli cells and of their surface specializations towards other Sertoli cells and towards germ cells is described. Sertoli cell nucleolar vacuoles, like those described in several ruminant species, were not found. The general appearance of the camel Sertoli cell suggests that its function is similar to that of other mammals.     

Clinical and anatomical studies of the camel (Camelus dromedarius) genitalia

Clinical and anatomical studies of the genitalia of 294 camel (197 males and 97 females) were carried out between May 1984 and October 1985. Preslaughter (clinical) examination was followed by detailed post-mortem (anatomical) examination and dissection of genitalia at the abattoir. Measurements and weights of the various segments of genitalia were made to establish the baseline data for breeding soundness evaluation in the dromedary in Northern Nigeria.     

Vascular supply of the testis of the camel (Camelus dromedarius).

The origin, pattern of distribution and the length of the convoluted part of the testicular artery were examined by blunt dissection and by the preparation of arterial casts with vinylite. The testicular artery originates from the abdominal aorta just cranial to its bifurcation and forms compact coils and reveals a tortuous course in the region of the pampiniform plexus and along the attached border. The artery divides at the caudal extremity of the testis into 2--4 branches. The epididymal artery, which is a branch of the testicular artery, was seen to anastomose with the deferential artery, but no anastomosis occurs between these arteries and the testicular artery. The convoluted part of the testicular artery was 20 cm in length, but when unravelled totalled 240 cm. This is not affected by seasonal variations. The possible significance of these results was discussed and compared with similar findings of other mammals.