Studies on liquefaction and storage of ejaculated dromedary camel ( Camelus dromedarius) semen

Abstract

The purpose of this study was to evaluate seminal liquefaction and quality of ejaculated camel semen during storage in different extenders at room (23 °C) and refrigeration (4 °C) temperature. Semen was collected using an artificial vagina and diluted immediately (1:1), using a split-sample technique, in five extenders [(1) Tris–tes egg yolk, (2) Tris–lactose egg yolk, (3) citrate egg yolk, (4) sucrose egg yolk and (5) Tris–fructose egg yolk], while one fraction was kept without an extender to act as control. The semen was transported to the lab at 37 °C, in a portable incubator within half an hour, and thereafter liquefaction of semen was monitored every 15 min. After complete liquefaction of the semen it was evaluated for sperm concentration and morphology and then was extended to a final ratio of 1:3. Aliquots of each semen sample were then stored at refrigeration and room temperature. The average volume of an ejaculate was 4.3 ± 0.4 mL and it had a very viscous consistency. The average concentration of spermatozoa was 230.4 ± 10.7 × 10 6 mL −1 and the proportion of spermatozoa with protoplasmic droplets averaged 1.02 ± 0.2, while 2.7 ± 0.6 and 9.7 ± 2.9% had mid-piece and tail abnormalities, respectively. All extended semen samples liquefied within 1.5 h at 37 °C, however, there was slow liquefaction in the sample without an added extender (control). Best liquefaction was observed in Tris–lactose extender followed by Tris–fructose and citrate egg yolk diluents whereas in the other two extenders there was head-to-head agglutination of the spermatozoa. There was no difference in the initial motility of the spermatozoa in extenders 1–5 after its liquefaction, however, after 24 and 48 h of storage a higher proportion of spermatozoa were motile in extenders 1, 2 and 4 ( P < 0.05) at both the temperatures. There was a gradual decline in viability of the spermatozoa in all extenders at both the temperatures, although, a high portion of the spermatozoa had intact acrosomes throughout the storage period. It may be concluded that dromedary semen, when added to an extender (1:1) immediately after collection, liquefies within 60–90 min at 37 °C. It maintains a high proportion of motile and viable spermatozoa that can survive storage up to 48 h in Tris–lactose egg yolk, Tris–tes egg yolk and sucrose egg yolk diluents. However, best liquefaction and progressive sperm motility is achieved in Tris–lactose egg yolk extender.