Gross morphological study on the epididymis of camel (Camelus dromedarius)

Introduction

The highly coiled ductus epididymis is the site for accumulation, storage, and further maturation of sperm. When sperm enter the epididymis, they are non-motile and incapable of fertilizing an oocyte. However, about a week later in transit through the ductus epididymis, the sperm acquire motility. The cell wall of epididymis also produces a glycoprotein that inhibits capacitation or the fertilizing ability of the sperm until they are deposited in the female reproductive tract (Singh and Bharadwaj, 1980) [19] .

Materials and Methods

The present study was conducted on 6 pairs of testes along with epididymis. The samples of epididymis were procured from TVCC (Training Veterinary Clinical complex) CVA'S RAJUVAS Bikaner, immediately after death of camels. The whole genitalia were carefully dissected out in recently dead animal (Figs 1 and2) and the measurements for physical parameters like length and thickness, of individual components were carried out on both the left and right epididymis. The length and thickness were measured by digital Vernier's calliper. The thickness was measured at three different regions i.e. head, body and tail. All recorded data were computed in tabular form. The data were analyzed by standard statistical method for mean (x), standard error (± SE) and paired "t" test used for depicting significant and non-significant correlation of data. The correlation between each parameter was calculated at 5% level of the significance for conclusion.

Results and Discussion

Topography

The epididymis of camel arosed from the cranial extremity of testis and faces lateral to the dorsal border (Figs 1, 2 and 3). These findings coincide with the observation made by Smuts and Bezuidenhout (1987) [21] in camel, Bravo et al. (2000) [5] in Camelidae, Hafez and Hafez (2001) [7] in camel, Zayed (2012) [24] in one-humped camel and Pasha et al. (2013) [13] in onehumped camel. However, Sisson and Grossman (1953) [20] reported that the epididymis lies along the lateral part of the posterior border in different animals, Raghavan (1964) [15] found epididymis was curved, overlapping a narrow area of lateral surface of the testicle, Ismail (1988) [10] noted that of the epididymis runs along the anterior border of the testis, extending from the ventral pole to a point slightly above the level of the proximal pole in one-humped camels, Sellnow (1996) [18] found that the epididymis was lightly attached to the upper surface of each testis in stallion's, Utiger (2008) [23] said that each epididymis lies on the top surface of the testis in humans, Belloa and Umarub (2013) [4] mentioned that the epididymis attaches to the anterior-dorsal point in camel, Pathak et al. (2014) [14] described that the epididymis started from the dorsal extremity of the testes in goat, Khan et al. (2016) [11] explained that the epididymis was found intimately attached with the testis border which was found long head and curved dorsal boundary in male goat, Saleem et al. (2017) [17] observed that the epididymis was located on the dorsomedial aspect of testis in the bird, Bello and Umaru (2020) [3] told that as in other species the epididymis was located along the dorsal border of the testis with the head curving around the cranial pole of the testis male one humped camel and Ibrahim et al. (2021) [9] claimed that in the dromedary camel epididymis was located at the cranial border of the testis and extends from the lower end to just above the upper border.

Shape and colour

The epididymis was highly convoluted duct, which was tightly packed in a thick tunica albuginea and an outer visceral layer of the tunica vaginalis (Fig 3). Result was in harmony with Cosentino and Cockett (1986) [6] in the bovine and Zayed (2012) [24] in one-humped camel and Ibrahim et al. (2021) [9] in the dromedary camel. Whereas Sisson and Grossman (1953) [20] further stated that the epididymis consists of a tortuous canal which forms the first part of the efferent duct of testes in different animals, Raghavan (1964) [15] revealed that the epididymis was elongated from above downward in the ox, Hafez and Hafez (2001) [7] noted that epididymis was very convoluted much smaller than in the stallion and bull, in camel, Utiger (2008) [23] mentioned that the epididymis, either of a pair of elongated crescent-shaped structures attached to each of the two male reproductive organs in humans. The color of camel epididymis was pinkish white. The tunica vaginalis was pigmented in some specimens (Fig 3). However, Khan et al. (2016) [11] stated that color of the epididymis was found pale to yellowish white in male goat.

External appearance

The epididymis was composed of three distinct parts as head (caput), body (corpus) and tail (cauda). The head was a bulbous mass curving around the cranial extremity of testis and attached by a fibrous band. Body of epididymis was thick flattened part attached lateral side to the dorsal border. The tail of epididymis was a small part which attached to the caudal extremity of testis by fibrous ligament and latter continuous with vas deferens. It also attached to the tunica vaginalis by a ligament (Fig 3). Same observation was also revealed by Raghavan (1964) [15] in ox, Cosentino and Cockett (1986) [6] in the mammalian epididymis, Ismail (1988) [10] in one-humped camels, Naggar and Rath (1990) [12] in camel, Zayed (2012) [24] in one-humped camel, Pasha et al. (2013) [13] in one-humped camel and Bello and Umaru (2020) [3] in male one Humped Camel. Result could not be confirmed with Tingari (1971) [22] , who mentioned that the avian epididymal region might be regarded as equivalent to the caput epididymis of scrotal mammals. Different regions of the ductus deferens were considered analogous to the corpus and cauda epididymis in the Rooster, Utiger (2008) [23] reported that the body was attached to the anal side of the testis and extends the length of the gland and the smallest region was the tail, which begins at the point of separation of the epididymis from the testis in humans, Belloa and Umarub (2013) [4] described that the tail of the epididymis was very closely opposed to the testicular surface by means of the epididymal ligament in camel, Pathak et al. (2014) [14] noted that the epididymis forming a globular flat rounded caput, which covered almost one fourth of the anterior border of the testis then turned on the lateral border and then descended along the postero-lateral border of the testis as the corpus, the tail was rounded or elongated tubercular like projection in goat, Khan et al. (2016) [11] explained that the epididymis body was fine and constricted lies beside the lateral part of the attached border of testicle, tail was long and directly attached at the ventral extremity of the testicle in male goat, Saleem et al. (2017) [17] found that the paired ductus deferens were tubular, convoluted and wavy in appearance, extending from caudal end of epididymis to the cloaca in the bird, Rashad et al. (2018) [16] stated that the epididymis composed of head, body and tail. The epididymal head was the heaviest and largest part of the epididymal segments. This enlargement in epididymal head was due to the presence of efferent ducts that were received from the testes in dromedary camel and Ibrahim et al. (2021) [9] clarified that gross anatomical description of epididymis had distinct regions like head (caput), body (corpus) and tail (cauda) in dromedary camel.

Length and width

The average lengths of right and left epididymis were 14.03 ± 0.78 cm and 14.52 ± 0.59 cm respectively (Table 1). The difference was non-significantly higher, representing that the left epididymis was larger than the right. However Cosentino and Cockett (1986) [6] revealed that epididymis was some 3 to 4 meters long in man, while in the bovine it may cover a total length of 40 meters, Ibrahim et al. (2012) [8] pointed out the three breeds Balami, Uda and Yankasa showed significant differences (p < 0.05, p < 0.01) in mean epididymal length the Uda had a significantly higher values (p < 0.05) followed by the Balami and the Yankasa, Abdullahi et al. (2012) [1] examined that there was no significant difference (p > 0.05) in mean epididymal length between the left and right organs, but there were numerical differences found of camels in the semi-arid environment, Rashad et al. (2018) [16] claimed that the length and their equivalent ratio from the whole organ varied significantly (p < 0.001) between epididymal segments, as the epididymal head was the heaviest and longest part in dromedary camel epididymis and Al-Sadoon et al. (2019) [2] noted that the differences between right and left epididymis were nonsignificant in males of arrabi and awassi sheep. The average width of right and left epididymis was 1.47 ± 0.14 cm and 1.59 ± 0.22 cm at head, 0.68 ± 0.09 cm and 0.73 ± 0.04 cm at body, 1.33 ± 0.04 cm and 1.35 ± 0.05 cm at tail (Table 1). The difference was statistically nonsignificant between right and left epididymis. While Hafez and Hafez (2001) [7] reported that the epididymis head small external diameter of 2 mm much smaller than in the stallion and bull in camel, Al-Sadoon et al. (2019) [2] noted that the differences between right and left epididymis were nonsignificant in males of arrabi and awassi sheep and Ibrahim et al. (2021) [9] epididymis was small tubules with a diameter of 2 mm in the dromedary camel epididymis.

Acknowledgement

AcknowledgementThe authors are thankful to the Dean, College of Veterinary and Animal science, Bikaner, RAJUVAS, Bikaner, Rajasthan for providing all the necessary facilities to carry out research work.

References

1. Abdullahi IA, Musa HAH, Jibril A. Scrotal circumference and testicular morphometric characteristics of the camel (Camelus dromedarius) in the semi-arid environment of northern Nigeria. Int J Morphol. 2012;30(4):1369-1372.
2. Al Sadoon AA, Al Yasery AJ, Al Khagani IY. Comparative morphological and anatomical study to development of testes and epididymis in males of Arrabi and Awassi sheep. Plant Arch. 2019;19(1):181190.
3. Bello A, Umarub MA. An overview on the anatomy and physiology of male one-humped camel (Camelus dromedarius) reproductive system. Afr Scholar J Afr Sustain Dev. 2020;17(2):141-152.
4. Bello A, Umarub MA. An overview on the anatomy and physiology of male one-humped camel (Camelus dromedarius) reproductive system. Sci J Rev. 2013;2(12):340-347.
5. Bravo PW, Skidmore JA, Zhao XX. Reproductive aspects and storage of semen in Camelidae. Anim Reprod Sci. 2000;62:173-193.
6. Cosentino MJ, Cockett ATK. Structure and function of the epididymis. Urol Res. 1986;14:229-240.
7. Hafez ESE, Hafez B. Reproductive parameters of male dromedary and bactrian camels. Arch Androl. 2001;46:85-98.
8. Ibrahim AA, Aliyu J, Ashiru RM, Jamilu M. Biometric study of the reproductive organs of three breeds of sheep in Nigeria. Int J Morphol. 2012;30(4):1597-1603.
9. Ibrahim ZH, Al Kheraije KA, Singh SK. Morphological and histochemical changes in the dromedary camel epididymis in relation to reproductive activity. Histol Histopathol. 2021;36(5):485-504.
10. Ismail STT. Reproduction in the male dromedary (Camelus dromedarius). Theriogenology. 1988;29(6):1407-1418.
11. Khan SA, Kalhoro IB, Gandahi JA, Tunio AN, Vistro WA, Ahmed M, et al. Gross anatomical studies on testis and epididymis at pre-pubertal and pubertal stages of teddy goat. Acad Res Int. 2016;7(1):51-57.
12. Pasha RH, Qureshi AS, Rehman ZU, Khamas WA. Seasonal anatomical changes in the testis of the onehumped camel. Eur J Anat. 2013;17(3):132-141.
13. Pathak A, Katiyar RS, Sharma DN, Farooqui MM. Postnatal developmental anatomy of testes and epididymis of Gaddi goats. Int J Morphol. 2014;32(4):1391-1398.
14. Rashad DEM, Kandiel MMM, Agag MA, El Khawagah ARM, GhM K, Mahmoud Ahmed YF, et al. Histomorphometry of dromedary camel epididymis and its correlation with spermatozoa characteristics during their epididymal transport. Benha Vet Med J. 2018;35(1):1-11.
15. Saleem R, Singh B, Khan IM, Singh I, Bharti SK. Gross and biometrical studies on male reproductive system of adult local fowl of Uttarakhand (Uttara fowl). Int J Pure Appl Biosci. 2017;5(3):634-638.
16. Singh UB, Bharadwaj MB. Histological studies on the testicular seminal pathway and changes in the epididymis of the camel (Camelus dromedarius). Acta Anat. 1980;108:481-489.
17. Tingari MD. Structure of the epididymal region and ductus deferens of the domestic fowl (Gallus domesticus). J Anat. 1971;109(3):423-435.
18. Utiger RD. Anatomy of the testes and epididymis. In: Encyclopaedia Britannica; 2008. Available from: Britannica.
19. Zayed AE, Aly K, Ibrahim IA, Maksoud FMAE. Morphological studies on the epididymal duct of the one-humped camel (Camelus dromedarius). Open J Vet Med. 2012;2:245-254.