الفهرس 
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Abstract
The epididymal spermatozoa recovery from slaughtered camels and its use in assisted reproductive technologies (AI, ET and IVEP) provide a useful mean to save their genetic material. Sperm DNA integrity is important for the accurate transmission of genetic information, and its damageis associated with reduced fertilization rates, pregnancy rates and embryo quality. Moreover, sperm morphology and ultrastructure playa key role in the fertilization processas the first step towards a newindividual assembly which perquisites both gametes to be structurallynormal, viable and functionally competent.
The present study was carried out on fifty epididymal samples collected during the breeding season from apparently healthy one-humped maturecamels (5-10 years old) at a local abattoir. The weight and length were measured in whole organ and each segment (head, body and tail). Spermatozoa were retrieved from each segment and evaluated for motility, livability, concentration, membrane integrity, acrosome integrity, ultra-structure and DNA integrity. Furthermore, epididymal tissue samples were processed for microscopic examination.
The data obtained in the current study showed that:1.The epididymal head weight and length were significantly (p˂0.001) larger than that of the body and tailsegments (8.96±0.49gand 10.09±0.51cm vs. 5.58±0.27 g and 5.95±0.35cm, and 5.35±0.32gand6.12±0.46cm, respectively).2. Microscopically, the camel epididymis appeared lined by stereo-ciliated pseudo-stratified columnar epithelium (contain five different cell types; principal, basal, apical, dark and halo cells that dissimilarly distributedbetween epididymal segments) and surrounded by a thin smooth muscular coat and an outer tunica serosa. 3.The luminal and tubular diameters of epididymal tail were significantly (p˂0.001) wider than that of the body and headsegments (511.63±58.19and 656.85±61.84µm vs.234±7.42 and 371.89±23.77µm, and195.96±9.88and 347.23±14.36µm, respectively).4.The epithelial and stereocilia heights of epididymal head were significantly (p˂0.024, p˂0.0001, respectively) taller than that of the body and tail segments (139.85±40.05and 27.19±4.00µm vs. 63.80±6.52 and 9.14±0.60µm, and35.1±3.40 and 4.51±0.65µm, respectively).5.The muscular coat thickness in the epididymal head significantly (p˂0.047) increased compared tothe body andtail regions (64.35±13.19µm vs. 27.14±1.84µm and 36.57±5.57µm, respectively).6.The epididymal intra-luminal cellular contentsin the head region, indicated by the histogram (in pixels), was significantly (p˂0.0001) higher than in tail and body regions (165.8±7.7vs. 139.4±5.8 and118.2±10.2, respectively).7.The motility and count were significantly(p˂0.01 and p˂0.001, respectively higher for spermatozoa from epididymal tail segment than head and body segments (58.13±2.82% and224±24.86 ×106/ml vs.13.33±2.25 % and 58.75± 10.87 ×106/ml, and39.17±1.68 % and 96.63±16.64 ×106/ml, respectively).8.The membrane and acrosome integrities were significantly (p˂0.0001and p˂0.005, respectively) higher for spermatozoa from tail segment than head and body segments (87.28±0.87 % and 95.68±0.99 % vs. 70.58±2.06 % and 90.61±0.45 % and 83.71±0.99 % and 91.53±0.58 %, respectively).9.The livability and normality weresignificantly(p˂0.05 and p˂0.0001, respectively) higher for spermatozoa from tail segment than head and body segments (82.84±2.97% and 66.67±2.47 % vs. 49.95±1.35 % and 47.07±2.31 % and 73.65±1.58% and 55.73±1.78 %, respectively).10. Immaturity of spermatozoa, indicated by the rate of protoplasmic droplet, was significantly (p˂0.0001) higher inspermatozoa from head than those from body and tail (19.08±1.06 % vs. 11.60±0.89 %and 8.00±0.78 %, respectively).11.The head and tail abnormalities were significantly (p˂0.005 and p˂0.001, respectively) higher in spermatozoa from head than those from body and tail (10.21±2.50% and 41.91±1.82% vs. 4.87±0.68% and 39.02±1.75%, and2.94±0.46 % and 30.38±2.24%, respectively).12.The acrosome length and perimeter were significantly(p˂0.001) larger for spermatozoa from head segment than body and tail segments (4.76±0.13µm and 19.02±0.28µm vs. 4.27±0.06 µm and 17.70±0.14µm, and 4.00±0.07 µm and 17.00±0.18µm, respectively).13. The DNA fragmentation detected by means of acridine orange staining showed a tendency (p=0.099) for difference between spermatozoa collected from epididymal head, body and tail segments. Spermatozoa from epididymal tail hadsignificantly (p<0.05) lower DNA fragmentation than those collectedfrom headsegment. Agarose gel electrophoresis revealed non-significant difference in DNA intensity or fragmentation between spermatozoa from the three epididymal regions.14.Ultra-structures of the epididymal spermatozoa showedchanges in acrosome shape, sub-acrosomal space, chromatin condensation and protoplasmic droplet during epididymal passage. Plasma membrane of most spermatozoa was slightly elevated at epididymal tail region.Protoplasmic droplets were numerous and dark in appearance in the head of the epididymis, dark and few in the body of the epididymis and few and light in the tail of the epididymis. Acrosome was projected anteriorly at the head segment and the acrosome projection became faded at tail segment. Sub-acrosomal space was wider at the head segment, narrower at the body segment, and was hardly to be found at tail segment.CONCLUSIONS The epididymal biometry and histological arrangement greatly differed between head, body and tail segments in mature camels. Spermatozoa fine structures obviously differed during sperm passage from the head to the tail of the epididymis.High stability of spermatozoa DNA integrity characterizedcamel spermatozoa during their passage from the head to the tail of the epididymis. These factors could critically influencethe sperm fertilizing capacity specially if they will be used in the assisted reproductive techniques such as IVF or ICSI in camels, with high priority should be directed toward the use of epididymal tail spermatozoa.