Seasonal Changes of Nuclear DNA Fragmentation in Boar Spermatozoa in Spain

Abstract

There are numerous cases when conventional spermiogram parameters are all within an acceptable range but boar subfertility persists. The total sperm nuclear DNA fragmentation index (tDFI) is a trait related to fertility and prolificacy problems that is not routinely evaluated in commercial AI boars. The aim of this research was to study the effect of the photoperiod, season and reproductive age of the boar on tDFI (measured by SCSA) of 1279 ejaculates from 372 different boars belonging to 6 different breeds located in 6 AI studs in Spain. tDFI data ranged from 0.018% to 20.1%. Although there was a significant single boar effect in the tDFI occurrence, a negative correlation between the tDFI and the age of the boar was found (p < 0.001). tDFI would decrease due to aging of the boar 0.66% each year old within the observed age range. After including age as a covariate in the ANCOVA, no differences were found in tDFI between photoperiods when the sperm collection date was evaluated. However, when the date of the production of semen in the testis was evaluated, the total percentage of spermatozoa with fragmented nuclear DNA was 1.46% higher in the increasing photoperiod in comparison to the decreasing photoperiod (p < 0.0001). On the other hand, for both dates, the lowest tDFI values corresponded to minimum day length for decreasing photoperiod phase (autumn), while the highest tDFI values were found in summer (maximum day length for decreasing photoperiod phase).

Retrospective analysis of commercial heterospermic and homospermic cooled boar semen: Effect of the season, sample type and shipping temperature on sperm quality

“…We observed a monthly mean of sperm DNA fragmentation of <6%, with higher values in summer or fall. Similar levels of sperm DNA fragmentation have been reported (López‐Fernández et al., 2008) with adverse response to season or heat stress (Ausejo et al., 2021; Peña et al., 2019). A relationship has been described between high sperm DNA fragmentation and frequency of proximal cytoplasmic droplets that occurred in summer to early fall (López‐Fernández et al., 2008), which was also identified in our study.…”

Single Fixed-Time Post-Cervical Insemination in Gilts with Buserelin

“…Additionally in boar, a reduction in sperm concentration was detected in spring and summer, although most seminal parameters were constant year-round [63]. As recently showed [64], DNA fragmentation was significantly higher when semen was produced in the increasing photoperiod respect to the decreasing photoperiod; the lowest values corresponded to autumn, while the highest values were found in summer.…”

Seasonal Variations on Testicular Morphology, Boar Taint, and Meat Quality Traits in Traditional Outdoor Pig Farming

“…However, some studies have noted a decrease in testicular steroids during the summer in domestic boars, which seems to be influenced by both daylight [ 18 ] and temperature [ 45 ]. While several studies have investigated the impact of the season on semen production and viability in domestic boars [ 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 ], limited research has been conducted on gonad morphometry [ 45 , 55 ]. Testosterone levels offer a means to assess how the season affects the state of gonad development, due to its connection with the hypothalamic–pituitary axis [ 54 ].…”