The generation of hydrogen peroxide (H 2 O 2 ) by ram spermatozoa (spz) was measured using a flurometric assay with 10-acetyl-3,7-dihydroxyphenoxazine agent as a probe for H 2 O 2 detection. The kinetics of H 2 O 2 production from both live and dead spz at 1 × 10 6 , 3 × 10 6 , and 6 × 10 6 spz/well concentrations were assessed in the tyrode albumin lactate (TAL) medium every 15 min for 120 min. An increase in H 2 O 2 production from both live and dead spz was noted with a significant difference (P < 0.05) between the 1 × 10 6 and 6 × 10 6 spz/well concentrations. Although dead sperm generated higher amounts of H 2 O 2 than live ones, no significant differences (P > 0.05) were observed between the two types of sperm for the three different concentrations. The generation of H 2 O 2 by ram spz was also compared in the presence and absence of nicotinamide adenine dinucleotide phosphate (NADPH) and phenylalanine, substrates of the two specific oxidases. The supplementation with these substrates significantly (P < 0.05) increased the amounts of H 2 O 2 generated from both live and dead spz, but for the two substrates, the increase was higher with dead than with live spz especially when phenylalanine was added. Addition of the antioxidant catalase significantly (P < 0.05) decreased the generation of H 2 O 2 by live and dead spz with no significant differences (P > 0.05) between the two types of sperm before or after the antioxidant addition. This study showed the ability of live and dead ram spz to generate H 2 O 2 in TAL medium. This ability was significantly influenced by the addition of NADPH and phenylalanine and also by the supplementation of the antioxidant catalase.

Abstract. The effects of month, electro-ejaculation (EE) and copulation process on testosterone and cortisol levels were investigated in Syrian Awassi rams. Jugular blood samples were collected from 10 rams at weekly intervals for 1 year. During the breeding and non-breeding season, samples were collected 60 min before EE and copulation as well as 0 (at the time of ejaculation), 20 and 60 min after EE and copulation. Low testosterone levels were detected from October to February (4.58-5.06 nmol L −1 ), while high levels were noted from May to September (8.01-11.40 nmol L −1 ) with significant differences among months (P <0.001). In contrast, cortisol levels were low from March to October (0.63-2.27 nmol L −1 ) and the highest level was recorded in December (11.30 nmol L −1 ) with a significant month effect (P <0.001). Cortisol reached its maximum concentration in the electrically stimulated rams 20 min post electro-ejaculation with no significant difference between the two seasons at this end time point. Means of testosterone levels differed between the breeding and the non-breeding season for electro-ejaculated rams. An increase in testosterone level was observed after 60 min of copulation process in the non-breeding, while no differences were noted for this hormone over the four time periods during the breeding season. Cortisol levels rose significantly in non-breeding season at 0 and 20 min after copulation (P <0.001). In conclusion, Syrian Awassi rams displayed a clear seasonality of testosterone and cortisol. Cortisol levels indicate an acute stress response to EE treatment. Females have an effect on testosterone and cortisol levels in Syrian Awassi rams only during the non-breeding season.

Dans cette étude, les effets de l’ajout de peroxyde d’hydrogène (H2O2), de nicotinamide adénine dinucléotide phosphate (NADPH) et de phénylalanine (substrats spécifiques d’oxydases) sur la mobilité des spermatozoïdes ont été étudiés. On a incubé des frais spermatozoïdes d’Awassi belier à 37 ºC pendant 30, 60, 120 et 180 minutes avec (100 uM et 1 mM) ou sans H2O2, NADPH et phénylalanine dans des milieux de Tris (EYT) et de Tyrode Albumen Lactate (TAL). La mobilité des spermatozoïdes a été évaluée à l’aide d’une analyse du sperme assistée par ordinateur (CASA). Après l’incubation des spermatozoïdes avec 100 μM de H2O2 aux différents intervalles de temps, aucun changement significatif (P> 0,05) n’a pas été observé comparé au contrôle par le pourcentage de mobilité (MOT%), la mobilité progressive (PMOT%) et la vitesse moyenne (VAP). L’incubation avec 1 mM de H2O2 a entraîné une diminution significative (P