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

Abstract

The aim of the present study was to evaluate the effect of the addition of two olive oil‐derived antioxidants, hydroxytyrosol (3,4‐dihydroxyphenylethanol, HT) and 3,4‐dihydroxyphenylglycol (DHPG), on ovine semen during liquid storage at 5°C and 15°C. Semen was collected, pooled, diluted and then divided into aliquots supplemented with different concentrations (5 μg/ml, 10 μg/ml, 50 μg/ml and 100 μg/ml) of HT, DHPG and a mixture (MIX) of both antioxidants. Sperm motility characteristics were assessed in the different samples at 0, 6, 24, 48, 72 and 96 hr after cooling, and a fertility trial was also conducted. The results showed that the antioxidant addition did not significantly improve total and progressive motility in ovine cooled sperm maintained at 15° or 5°C. However, in samples stored at 5°C, LIN (48, 72, 96 hr), STR (0 hr) and WOB (0, 48, 72, 96 hr) values significantly decreased in comparison with control treatment when high antioxidant concentrations were added (MIX100 or HT100). When samples were maintained at 15°C, MIX50 showed significantly higher VCL values than the control treatment after 6 hr cooling, and MIX100 showed significantly lower VCL values at 96 hr after cooling. According to the artificial insemination trial, no significant differences were observed when antioxidants were added. In conclusion, the use of HT and DHPG showed small impact in sperm motility and fertility was not affected (nor detrimentally nor positively) when insemination was carried out using antioxidant‐supplemented liquid sperm.

Bayesian Analysis of the Effects of Olive Oil-Derived Antioxidants on Cryopreserved Buck Sperm Parameters

“…Contextually, HT-supplemented sperm extender has previously been evaluated in studies conducted on rats [22], humans [23], and rams [15,24,25]. However, the effect of DHPG supplementation has only been reported in ram sperm [15,25]. Taking into account the properties of both antioxidants, the present study hypothesizes that extenders supplemented with these compounds might counteract the sperm damage inflicted by the cryopreservation process.…”

“…In this sense, several studies have evaluated the use of exogenous antioxidants in goat sperm [3,[8][9][10][11]. In this framework, a large number of natural compounds has been tested in cell cultures assessing the antioxidant, anti-inflammatory or chelating properties of antioxidants, in recent years, e.g., mentha [12], Feijoa sellowiana [13], grapes [14], or olives [15].…”

“…By contrast, there are few studies on the effects derived from the addition of these antioxidants to sperm dilution media in animals. Contextually, HT-supplemented sperm extender has previously been evaluated in studies conducted on rats [22], humans [23], and rams [15,24,25]. However, the effect of DHPG supplementation has only been reported in ram sperm [15,25].…”

Effects of Gossypium spp., Balanites aegyptiaca, and Sesamum indicum seeds oils on quality of chilled and frozen-thawed ram semen

“…According to their origin, there are two types of antioxidants: Those produced synthetically, which have been used since 1995, and those formed naturally, antioxidants contained in vegetable oils, used recently to preserve better sperm quality. Many scientific reports have analyzed the effects of vegetable oils on semen quality, either as an animal diet supplementation [33][34][35][36][37][38][39][40] or as a cryoprotectant substance in sperm extenders [20][21][22][23][24][25][41][42][43][44].…”

“…It is, therefore, essential to find safer sperm-freezing alternatives. Recently, studies have focused on testing alternative extenders free of animal substances, such as soybean lecithin [4,5,6,[13][14][15][16][17] or extenders supplemented with polyunsaturated fatty acids [18,19] or with vegetable oils, such as argan oil, olive oil, Rosmarinus officinalis oil, Nigella sativa oil, and Origanum vulgare oil [20][21][22][23][24][25][26] to preserve animal sperm. Other vegetables such as Gossypium spp., Balanites aegyptiaca, and Sesamum indicum, available widely in Africa, including Niger, also contain lecithin protein and unsaturated fatty acids [27][28][29], but have not yet been tested for sperm cryopreservation.…”