Refrigerated storage of ram sperm in presence of Trolox and GSH antioxidants: Effect of temperature, extender and storage time

Abstract

Antioxidants have a potential to improve the quality and fertility of refrigerated-stored ram semen. Reduced glutathione (GSH) and Trolox (0.2, 1 and 5mM) were evaluated in ram semen preserved at 15 and 5°C up to 48 and 96h, respectively. Extenders were also evaluated (15°C: Tris-citrate-fructose, TCF, without lipids, and TES-Tris-fructose 10% egg yolk, TTF-EY; 5°C: TTF-EY and 3.5% soybean lecithin, TTF-SL; INRA96 at both temperatures). Storage at 5°C resulted in poorer quality than 15°C up to 48h, while allowing acceptable quality at 96h. Antioxidants had few effects on sperm quality, with use of Trolox resulting in reduced motility and viability in TCF. Storage at 15°C in the TCF extender resulted in decreased motility, viability and mitochondrial activity compared with use of TTF-EY. Sperm quality when storage was at 5°C was similar, but storage in TTF-SL resulted in decreased motility and mitochondrial activity. Acrosomal status was only slightly affected by extender and antioxidant. Mitochondrial activity was improved by antioxidants in TTF-SL, and GSH at 5mM when semen was stored at 5°C in TTF-EY. A preliminary artificial insemination trial indicated that supplementation with GSH has the potential for improving lambing (P<0.1). In conclusion, use of antioxidants resulted in lesser effects than extender composition or storage time on quality of ram semen. Use of Trolox negatively impacted sperm quality and GSH had some positive impacts. The use of soybean lecithin requires further research to assess its impact on mitochondria.

Effect of olive‐derived antioxidants (3,4‐dihydroxyphenylethanol and 3,4 dihydroxyphenylglycol) on sperm motility and fertility in liquid ram sperm stored at 15°C or 5°C

“…However, lower sperm motility and metabolism could be associated with pH reduction due to bacterial contamination and metabolite production (Yániz, Mateos, & Santolaria, ). Previous studies reported that 15°C is the optimal temperature to maintain a good percentage of motile cells and a high motility score during short‐term storage (Upreti, Oliver, Munday, & Smith, ), while the storage of semen at 5°C is clearly advantageous for long‐term storage (Mata‐Campuzano et al, ).…”

“…However, the implementation of this technique in ovine is far away that which occurs in bovine or porcine. In order to explain the slow development of this technique in ovine, it can be argued the low economical profitability of these farms, the high variability of the fertility rates or the loss of sperm quality associated with cryopreservation or cooling process (Mata‐Campuzano et al, ).…”

In vitro developmental ability of ovine oocytes following intracytoplasmic injection with freeze-dried spermatozoa

“…Several studies 16–19, 34 have shown the beneficial effect of antioxidant therapy on the oxidative stress of mammalian spermatozoa. The addition of antioxidants has important benefits on the quality and fertility of ram semen after liquid storage at different temperatures 35 . To date, there have not been studies focus on determine the antioxidant effect on freeze dried sperm.…”

The effect of quercetin on fertility of frozen-thawed ram epididymal spermatozoa

“…The female size, low economic return, variable fertility rates, and more rapid loss of semen quality with storage time are important obstacles for the routine use of these techniques. Therefore, sperm quality, which is negatively affected by cryopreservation, has a critical impact on the application of AI (Mata-Campuzano et al, 2014;Najafi et al, 2014).…”