GSX-Px ACTIVITY, SELENIUM CONCENTRATION AND SEMEN QUALITY ON RAMS SUPPLEMENTED WITH SELENIUM DURING REPRODUCTION ESTAGE

Abstract

There are diagnosed trace minerals deficiencies in grazing sheep in Mexico, but few strategies to correct and evaluate their response are available. Our objective in this study was to evaluate, in rams (10 Hampshire 80.6±7.6 kg LW and eight Suffolk 86.3±9.3 kg LW), the effect of a sodium selenite supplement in an extended-release intraruminal bolus (500 mg of Se), on the LW, body condition, scrotal circumference, blood variables, glutathione peroxidase activity, selenium concentration in blood serum and characteristics of the ejaculate. The experimental design was completely randomized with a 2x2x3 factorial arrangement without and with Se (intraruminal bolus), breeds (Hampshire and Suffolk) and three months during the breeding season (November, December and January), where each ram was the experimental unit. Blood samples were obtained in weeks one (before treatment), two and three in July 2005, and then, in the fourth week of each month (August 2005 to February 2006). The ejaculate of the rams were sampled every week from November to January, using an artificial vagina. Every day (08:00 h), before grazing, the rams received a concentrated feed (1 % PV), grazed on Pennisetum clandestinum pastures during the day, and were confined at night. The supplied Se increased (p£0.05) GSH-Px activity, mobility and number of live and normal sperm. The ejaculate quality was higher (p£0.05) in volume, density, concentration and viability on the Suffolk rams. In conclusion, a Se supplement in intraruminal boluses increased GSH-Px activity, mobility and viability of the ejaculate in Hampshire and Suffolk rams during their breeding season.