Effect of Sperm Concentration and Storage Temperature on Goat Spermatozoa during Liquid Storage

Abstract

The use of cooled semen is relatively common in goats. There are a number of advantages of cooled semen doses, including easier handling of artificial insemination (AI) doses, transport, more AI doses per ejaculate, and higher fertility rates in comparison with frozen AI doses. However, cooled semen has a short shelf life. The objective of this study was to examine the effect of temperature and sperm concentration on the in vitro sperm quality during liquid storage for 48 h, including sperm motility and kinetics, response to oxidation, mitochondrial membrane potential (MMP) and DNA fragmentation in goats. Three experiments were performed. In the first, the effects of liquid preservation of semen at different temperatures (5 °C or 17 °C), durations (0, 24 and 48 h) and sperm concentrations (250 × 106 sperm/mL (1:2 dilution rate), 166.7 × 106 sperm/mL (1:3 dilution rate) or 50 × 106 sperm/mL (1:10 dilution rate)) on sperm motility and kinetics were studied. In the second experiment, the effect of temperature, sperm washing and concentration on sperm motility and DNA fragmentation was studied. Finally, the effect of sperm concentration and duration of storage at 5 °C on sperm motility, response to oxidative stress and MMP was examined. We found that refrigerated liquid storage of goat sperm impaired sperm quality, such as motility, MMP and response to oxidation, as storage time increased; however, sperm DNA fragmentation index was not significantly affected. Liquid storage at 5 °C preserved higher total motility than at 17 °C. Moreover, we observed that the reduction of sperm concentration below 500 × 106 sperm/mL did not seem to improve the quality of spermatozoa conserved in milk-based extender in the conditions tested.

Influence of Season and Liquid Storage at 16 °C on Beni Arouss Bucks’ Semen Quality

“…Results of semen preservation at 16 • C in a synthetic extender for 24 h indicate that the semen quality dropped progressively between 0 and 24 h of storage. These observations are in line with previous studies showing that during liquid storage, all variables evaluating motility, viability and normal morphology undergo a significant decrease, regardless of the extender in use, dilution rate, temperature and storage conditions [24,25]. This storage-related quality loss was further subjected to seasonal changes.…”

Effect of the donor's age and type of extender (egg yolk versus clarified egg yolk) over the sperm quality of Majorera bucks preserved at 4°C: In vitro results and fertility trials

“…Progressive sperm motility was slightly modified for the first 48 hr of cooling, and no significant differences between young and adult bucks were detected. Previous studies developed in the same breed (Batista et al., 2011, 2014) showed practically similar values in sperm motility of stored semen at 4°C for 24–48 hr and were comparable when the sperm quality was assessed in chilled semen, whether the diluent used was based on egg yolk (Tabarez et al., 2017) or skimmed milk (Mocé et al., 2020; Sadeghi et al, 2020; Salvador et al., 2006) with medium values between 50% and 65% for the first 48 hr of chilling. In our study, sperm motility was reduced after 72 hr of storage, regardless of the diluent used or the age of the males; as a general rule, as the preservation time increases, a decrease in sperm motility is observed, probably as a consequence of metabolic depletion of sperm (Bashawat et al., 2021), being a fact to take into account, in order to reach an adequate fertility rate.…”

Factors Affecting the Survival of Ram Spermatozoa during Liquid Storage and Options for Improvement

“…Gungdogen et al's, 2010 investigation demonstrated these consequences when ram spermatozoa were diluted to 100 × 10 6 sperm/mL and recorded lower membrane damage and oxidative stress compared to spermatozoa diluted to 25 × 10 6 sperm/mL. Research has demonstrated this result in other species with various sperm concentrations, including rabbits [42], cattle [43,44], bucks [45], and pigs [46].…”