Evaluation of Chilled Dog Semen Extended With Sperm Activator

Abstract

Within modern biotechnology, different tools and methodologies have been developed to maximize canine semen conservation protocol to optimize reproductive results. In the last decades, the survival of chilled semen has been prolonged from 2 to 3 days with the first basic diluents, to 10–14 days with the modern extenders. However, their main limitation is that sperm quality decreases during cold storage. Sperm activators (SA) have been produced to provide the molecules necessary to maximize the sperm survival and quality with the aim to enhance fertility and prolificacy. In this study, the effect of commercial extender SA (Theriosolution® Canine AI extender -Chile-) was recorded by daily evaluation of chilled semen for 14 days. In this experiment, sperm-rich ejaculate fraction was collected from six adult healthy Neapolitan Mastiff dogs. The semen evaluation started immediately after collection (d0), and after that a next generation extender was added (d0) for every 24 h from d1 (with and without SA) to d14, to determine spermatozoa progressive motility, velocity of forward progression (VFP), morphology, and integrity of the spermatic membrane. The initial sperm concentration of extended semen was 417.3 ± 170.4 x 106/mL (mean ± SEM) with 85.89 ± 4.76% of MNS (morphologically normal sperm), 84.47 ± 5.22 % live sperm, and pH of 6.2 ± 2.8. The initial VFP was 3.83 ± 0.48, but after 1 min with SA, it rises to 4.45 ± 0.45 (P < 0.001). The sperm progressive motility parameter increases significantly (P < 0.05) in experimental trial, respect to control, starting to d2 at finish (except for d7). The VFP analysis significantly increases in experimental trial (P < 0.05) during most days of the study with the exclusion of d3 and d14. To evaluate the seminal characteristics over time, the experiment was divided into T1 (d0–d5), T2 (d6–d10), and T3 (d11–d14) (P < 0.001) in evaluation of morphology and membrane functionality. The MNS reached 70% at d10 and finally 65% at d14, being considered normal and possibly fertile. With Host-s, 65% of MNS were also achieved at d14. The presence of glucose and fructose in the diluents used for refrigeration can exert very important effects given the fact that metabolic routes have been found in both sugars, providing both different and complementing effects. It can be concluded that the use of SA prior to artificial insemination improves the quality of chilled semen significantly, although it does not reverse the effects of deterioration due to cellular metabolism over time.

Effect of Seminal Plasma Protein Fractions on Cooled Dog Semen Kinetics

“…Such a property was observed in human ZnBP (20). Some authors noted that the addition of prostatic fluid may have a positive effect on the fertilization capacity of extended and cooled canine spermatozoa (2,21). This study aimed to determine GPC separated seminal plasma proteins that could have a positive effect on canine spermatozoa cooled at 4 °C.…”

“…The fundamental problems associated with artificial insemination using cooled dog semen involve variations in storage temperatures, variable semen quality between dogs, poor spermatozoa survival rates, disturbance of sperm motility, DNA fragmentation and etc. (1,2,3,4). The low fertility of cold shocked spermatozoa are primarily result of sperm plasma and acrosome membrane damage (2).…”

“…(1,2,3,4). The low fertility of cold shocked spermatozoa are primarily result of sperm plasma and acrosome membrane damage (2).…”

Photoperiod and Melatonin Supplementation: Variable Effects on the Quality of Chilled Dog Semen

“…Recently, chilled canine semen can survive until 10–14 days due to modern extenders; however, sperm quality decreases during cold storage ( 23 ). In this study, mobility parameters, TM, PM, VAP, VCL, VSL, and WOB, did not vary significantly over time in both photoperiods.…”

Molecular Biomarkers of Canine Reproductive Functions

“…The available literature is dominated primarily by reports on the addition of sugars (glucose, fructose) to semen extenders [ 212 ] or basal medium [ 213 ]. Sugars have long been incorporated into semen diluents as exogenous energy substrates, osmotic constituents, and cryoprotective agents [ 214 ]. The carbohydrate composition of dog semen (sperm and seminal fluids) and the impact of individual sugar components on semen quality need to be investigated to fill the existing lack of current knowledge.…”