96 A NOVEL EXTENDER FOR PRESERVATION OF BACTRIAN CAMEL (CAMELUS BACTRIANUS) SEMEN

Lactose and Green buffer (IMV, France) are the most commonly used extenders for camel semen. The viability of Bactrian camel spermatozoa in lactose extender is reduced after 4 h of incubation at 4°C (unpublished data). Although Green buffer is used for dromedary camel semen, there are no data indicating its effectiveness for Bactrian camel semen. More recently, we reported that the osmolality and pH of Bactrian camel semen are 316.1 ± 1.48 mOsm/kg and 7.4 ± 0.03, respectively. The objective of this study was to compare three different semen extenders, to determine if a TRIS-based diluent (SHOTOR* Diluent), a completely defined diluent, can maintain cooled camel sperm as effectively as established diluents. SHOTOR Diluent consists of 2.6 g TRIS, 1.35 g citric acid, 1.2 g glucose, and 0.9 g fructose in 100 mL of deionized water, with an osmolality of 330 mOsm/kg and pH of 6.9. SHOTOR Diluent, lactose, 10% (w/v), with an osmolality of 330 mOsm/kg and pH of 6.9, and Green buffer were compared in this study. All extenders contained 20% egg yolk. Semen was collected from bulls with a sound history of semen quality and fertility (n = 3), using a modified artificial vagina, and divided equally into the different extenders (Mosaferi S et al. 2004 15th Int. Cong. Anim. Reprod. 2, 520; Mosaferi S et al. 2004 Theriogenology, in press). Progressive forward motility and percentage of live spermatozoa were examined at the time of semen collection (time 0) and after 4, 12, and 24 h of incubation at 4°C. Data were analyzed using the GLM procedure in SAS/STAT after arcsine transformation. The forward progressive motilities of spermatozoa at 0, 4, 12, and 24 h after semen collection were 65.5, 54, 44.5, and 36.5% in SHOTOR Diluent; 31, 18.5, 8.5, and 0% in 10% lactose; and 60.5, 54.5, 33, and 32.5 % in Green buffer, respectively (Table 1). The percentage of live spermatozoa at 0, 4, 12, and 24 h were 84.5, 84, 81 and 74.5% in SHOTOR Diluent; 80, 79.5, 72.5, and 56.5% in 10% lactose; 89, 82.5, 82.5, and 77.5% in Green buffer, respectively (P > 0.05). The progressive forward motility of spermatozoa did not significantly decrease by 12 h at 4°C in SHOTOR Diluent (P > 0.05; Table 1), whereas it significantly decreased after 4 h and 12 h of incubation at 4°C in Green buffer and 10% lactose, respectively (P < 0.05; Table 1). Further decrease in the progressive forward motility occurred in all extenders after 24 h at 4°C (P < 0.05; Table 1). In conclusion, SHOTOR Diluent is better than Green buffer and 10% lactose as an extender for chilled storage of Bactrian camel semen for 12 hat4°C. Table 1. The progressive forward motility of Bactrian camel spermatozoa extended in SHOTOR Diluent (1), 10% lactose (2) and Green buffer (3) at the time of semen collection (time 0) and after 4, 12, and 24 h of incubation at 4°C *Shotor means camel in the Persian language. The authors wish to thank the director and station staff of Bactrian Camel Reseach Center at Meshkinshahr, Ardabil, for providing facilities and kind assistance throughout the experiment.