Environmental Factors Related to a Semiarid Climate Influence the Freezability of Sperm from Collared Peccaries (Pecari tajacuLinnaeus, 1758)

Abstract

The influence of environmental factors in a semiarid climate on characteristics of fresh and frozen/thawed sperm collected from collared peccaries (Pecari tajacu) was assessed. Semen from 11 male collared peccaries was collected by electroejaculation during the peaks of the dry and rainy periods while rainfall indices, air temperatures, relative humidity levels, and wind speeds were measured. The number, motility, morphology, osmotic response, and membrane integrity of sperm in the collected ejaculates were assessed. Samples were then frozen in liquid nitrogen, thawed, and reassessed. The rainfall index of the rainy period (73.2 mm) was significantly higher than that of the dry period (13.6 mm) and the relative humidity was significantly higher during the rainy period (74.6%) than it was during the dry period (66.8%). Air temperature and wind speed did not differ between the two periods. Characteristics of sperm in the fresh samples were not affected by environmental parameters. In contrast, computerized analysis revealed that sperm in samples frozen during the rainy period exhibited better post-thaw membrane integrity (28.6 ± 6%), motility (29.5 ± 7.7%), and rapid sperm population (13.7 ± 6.2%) than did sperm in samples frozen during the dry period (23.4 ± 3% membrane integrity, 14.6 ± 4.1% motility, and 4.1 ± 1.2% rapid sperm; p < 0.05). Other characteristics of the frozen/thawed sperm did not differ depending on the period in which they were collected. We demonstrated that environmental parameters did not affect the quality of fresh sperm, but could influence the freezability of sperm collected from collared peccaries raised under a semiarid climate.

Catalase and superoxide dismutase supplementation to the diluent for cryopreservation of collared peccary semen

“…In fact, studies that investigated SOD, CAT and GPX in collared peccary seminal plasma were conducted during the dry season of the Caatinga biome (Santos et al, 2014(Santos et al, , 2018, while the present study took place during the rainy season. In this species, it is known that the season has a marked effect on semen freezeability, with the best post-thawing results being obtained precisely in the rainy season (Maia et al, 2018). Thus, it is possible that there are compensatory effects related to the antioxidant mechanisms of the seminal plasma of peccaries during the rainy season, which highlights the need to investigate such endogenous mechanisms also in this climatic period.…”