Characteristics of Antioxidant Systems of Yellow Fraction of Red Deer's (Cervus elaphusL.) Semen During the Rutting Period

Changes in the Morphology and Antioxidant Status of European Red Deer Sperm Stored in the Epididymides and in a Liquid State

The aim of this study was to evaluate the motility, morphology, and antioxidant status of European red deer sperm stored in a liquid state (variant I) and in the epididymides (variant II). Spermatozoa were harvested post-mortem from the cauda epididymis. Sperm samples in both variants were stored for up to six days (D6) at 5 °C. Spermatozoa were assessed for motility, viability, morphology, activity of antioxidant enzymes (superoxide dismutase, SOD; glutathione peroxidase, GPx; catalase, CAT), and lipid peroxidation (malondialdehyde, MDA, content). Sperm samples were analyzed on storage days 0, 2, 4, and 6 (D0-D6). Storage time and storage method significantly (p ≤ 0.05) influenced the examined variables. On D2, a decrease in motility and acrosomal integrity was observed in both storage variants, whereas a decrease in viability and an increase in MDA content were noted in spermatozoa stored in the epididymides. On D4, higher values of SOD and GPx activity and MDA content were noted in variant I than in variant II. Catalase activity was very low. GPx is the key enzyme that participates in the reduction of hydrogen peroxide in sperm cells. Spermatozoa stored in a liquid state were characterized by higher motility and viability, improved morphology and antioxidant status than those stored in the epididymides; therefore, liquid storage is more recommended for short-term preservation of epididymal spermatozoa.

Impact of Seminal Plasma Composition on Sperm Freezability in Wild Mammals: A Review

This review was designed to summarize the most important information around seminal plasma composition and discuss its impact on the freezability of wild mammal semen samples. Seminal plasma is made up of various biochemical constituents, including ions, lipids, proteins, enzymes, and sugars, which vary between species in response to the presence and size of any relevant accessory glands. The biochemical constituents of seminal plasma may change as a result of age, individual variability, and seasonality. These constituents are responsible for supporting different functions in sperm cells, contributing to motility, acrosomal reaction, and fertilization events. A detailed understanding of seminal plasma biochemistry may help to optimize semen freezing protocols, enabling the dynamic alteration in diluents to allow for increased sperm viability rates after thawing.

The incorporation of cystine by the soluble carrier family 7 member 11 (SLC7A11) is a component of the redox regulatory mechanism in stallion spermatozoa†

Oxidative stress is considered a major mechanism causing sperm damage during cryopreservation and storage, and underlies male factor infertility. Currently, oxidative stress is no longer believed to be caused only by the overproduction of reactive oxygen species, but rather by the deregulation of redox signaling and control mechanisms. With this concept in mind, here, we describe for the first time the presence of the soluble carrier family 7 member 11 (SLC7A11) antiporter, which exchanges extracellular cystine (Cyss) for intracellular glutamate, in stallion spermatozoa, as well as its impact on sperm function using the specific inhibitor sulfasalazine. Spermatozoa incubated with Cyss exhibited an increased intracellular GSH content compared with controls (P < 0.01): 50% in fresh extended stallion spermatozoa and 30% in frozen-thawed spermatozoa. This effect was prevented by the addition of sulfasalazine to the media. Cystine supplementation also reduced the oxidation-reduction potential of spermatozoa, with sulfasalazine only preventing this effect on fresh spermatozoa that were incubated for 3 h at 37°C, but not in frozen-thawed spermatozoa. While sulfasalazine reduced the motility of frozen-thawed spermatozoa, it increased motility in fresh samples. The present findings provide new and relevant data on the mechanism regulating the redox status of spermatozoa and suggest that a different redox regulatory mechanism exists in cryopreserved spermatozoa, thus providing new clues to improve current cryopreservation technologies and treat male factor infertility.

Physiological variations in reproductive and metabolic features of white-tailed deer (Odocoileus virginianus) bucks throughout the rutting season

White-tailed deer farming is a growing industry in the United States, yet there is still a need to improve breeding practices in captive cervids. The objective of this study was to compare reproductive and somatic characteristics of white-tailed bucks early in the breeding season (September), at peak rut (December), and late breeding season (March). We hypothesized that reproductive parameters would improve at the peak of the breeding season. Young, mature bucks (n = 7-11, ages 2-3 yr) were anesthetized via projector with tiletamine-zolazepam and xylazine. Semen was collected by electroejaculation and evaluated for sperm output, motility, and morphology. The bulbourethral, vesicular, and prostate glands were measured by transrectal ultrasound. Body condition score, thoracic circumference, rump fat thickness, scrotal circumference, and testicular measurements were also recorded. Serum testosterone, estradiol, and IGF-I concentrations were measured. Body condition score and rump fat thickness were highest in September, intermediate in December, and lowest in March (p < 0.01), whereas thoracic circumference was lowest in September (p = 0.02). In September, serum IGF-I was highest (p < 0.01) and estradiol was lowest (p ≤ 0.02). Serum testosterone levels were lowest in March and highest in December (p < 0.01). Testicular volume and scrotal circumference were highest in September, intermediate in December, and lowest in March (p < 0.01). Bulbourethral gland length was greatest in March (p ≤ 0.05), whereas prostate length was greatest in September (p ≤ 0.02). Vesicular gland length and width were highest in December, intermediate in September, and lowest in March (p ≤ 0.02). Both overall and progressive sperm motilities were lowest in March (p < 0.01), but did not differ between September and December (p ≥ 0.12). In December, bucks had the highest percentage of normal sperm and lowest percentage of primary sperm defects (p ≤ 0.01). Collectively, our results demonstrated variation in reproductive and metabolic characteristics of white-tailed deer bucks throughout the breeding season at 40°N. The physiological variations described here will be useful for veterinarians and researchers performing reproductive evaluations in white-tailed deer bucks.