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The aim of this study was to evaluate the effect of in vitro treatment of ejaculated ram spermatozoa with different concentrations of L-arginine at various incubation times on motility, hyperactivity (HA) and acrosome reaction. Freshly ejaculated spermatozoa collected from three rams were pooled and subjected to the swim up technique in modified sperm Tyrode's albumin lactate pyruvate (S-TALP) medium supplemented with different concentrations of Larginine (0.01, 0.02, 0.03,0.04 and 0.05 mM) at 30, 60,90 and 120 min of incubation. Following sperm incubation, the following parameters were examined: motility, hyperactivity (HA) and acrosome reaction (AR). The results showed that irrespective of the concentration, incubation of ram spermatozoa with Larginine for 30min did not significantly affect the motility. However, increase the time of incubation for more than 30 min significantly decreased (P < 0.05) the motility of the spermatozoa as compared to the control. The lowest motility was recorded when spermatozoa were incubated with 0.05 mM L-arginine for 120 min. Treatment of ram spermatozoa with 0.05 mM Larginine resulted in a significant (P < 0.05) increase in HA% immediately after dilution compared to the control. A significant (P < 0.05) increase in total AR% was concomitant to the increase in the concentration of L-arginine with highest AR achieved at 0.04 mM and 90 min incubation. However, increasing the time of incubation to 120 min significantly decreased (P < 0.05) the percentage of spermatozoa with total AR compared to the other incubation times at 0.02, 0.04, and 0.05 mM L-arginine. In conclusion, under our experimental conditions treatment of ejaculated ram spermatozoa with 0.04 mM of L-arginine for 90 min was considered the best concentration of L-arginine to be used for in vitro induction of acrosome reaction.

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The present study was designed to study the influence of different concentrations of oviduct fluid (OF) and follicular fluid (FF) on ram sperm capacitation and acrosome reaction in vitro. Forty semen samples were collected from three Barki rams throughout the period of study (10 weeks). Fresh semen was evaluated, layered under S-TALP (sperm Tyrode’s albumin lactate pyruvate) medium and subjected to swim up techniques. Split fractions of semen were incubated in media enriched with different levels of OF (10, 20, 40, 50 and 75 µL/mL) or FF (10, 20, 40, 50, 100, 150 and 200 µL/mL). Best concentrations were compared and used to evaluate the ram sperm functions including progressive motility, hyperactivity and acrosome reaction. The present findings showed a significant increase in individual motility percentage (IM %) when ram spermatozoa were treated with 10 and 50 µL of oviduct fluids as compared to the other treatments after 1 h of incubation. Addition of 50 µL/mL of OF or FF had beneficial effect on sperm hyperactivity after 2 and 1 h incubation respectively. Furthermore, addition of 50 µL/mL oviduct fluid to ram sperm maintained significantly (P < .05) higher total acrosome reaction (AR %) after 3 h of incubations than those observed in other groups. In conclusion, treatment of ram spermatozoa with 50 µL/mL of OF or 40 µL/mL of FF for 3–4 h incubation respectively was considered the best level of oviduct or follicular fluid to be used for IVF.