We compare the efficiency of mechanical or enzymatic methods, and their combination, for the isolation of ovarian preantral follicles (PFs) from collared peccaries. The ovaries from six females were subjected to the different methods investigated here. For the enzymatic method, ovary fragments were exposed to collagenase type IV in TCM-HEPES medium; the mechanical procedure was based on ovarian cortex dissociation by using a scalpel blade. The residual solution obtained after the mechanical isolation was subjected to the enzymatic procedure. The number of isolated PFs was quantified and classified as primordial, primary, or secondary; their viability was assessed using trypan blue dye assay. To confirm the results, PFs derived from the most efficient method were evaluated for integrity using scanning electron microscopy (SEM) and subjected to a 24 h in vitro culture for subsequent evaluation of viability by using fluorescent probes. A higher number of PFs (P < 0.05) was obtained from the enzymatic method (961.7 ± 132.9) in comparison with the mechanical method (434.3 ± 88.9), but no difference was observed between the two methods and their combination (743.2 ± 92.8). The trypan blue assay showed that the enzymatic method (98.7 ± 0.6%) provided the highest percentage of viable follicles (P < 0.05). Furthermore, SEM confirmed the ultrastructural integrity of the surface architecture of peccary PFs isolated by the enzymatic procedure; epifluorescence microscopy was used to confirm their viability (86.0%). In conclusion, we suggest that the enzymatic method investigated here is useful for the isolation of viable ovarian PFs from collared peccaries.

The aim of this study was to establish a functional freezing–thawing protocol for epididymal sperm of collared peccaries (Pecari tajacu L., 1758) by comparing different extenders. The epididymal sperm from 12 sexually mature males was recovered by retrograde flushing using Tris-based or coconut water-based (ACP®-116c) extenders. After initial evaluation, samples were diluted and frozen with the same extenders to which 20% egg yolk and 6% glycerol were added. After 2 weeks, thawing was performed at 37°C/60 s and sperm motility, vigour, morphology, functional membrane integrity, sperm viability, sperm plasma membrane integrity, and a computer-assisted semen analysis (CASA) were assessed. In addition, to evaluate the survival of frozen–thawed sperm, a thermal resistance test (TRT) was executed. Samples preserved using Tris were in better condition compared with those preserved using ACP®, showing higher values for most assessments performed, including CASA and the TRT (P<0.05). After determining Tris to be the better of the two extenders, additional samples were thawed using different thawing rates (37°C/60 s, 55°C/7 s, 70°C/8 s). Sperm thawed at 37°C/60 s had the greatest preservation (P<0.05) of viability (54.1 ± 5.9%) and functional membrane integrity (43.2 ± 5.4%), and had higher values for various CASA parameters. In conclusion, we suggest the use of a Tris-based extender added to egg yolk and glycerol for the cryopreservation of epididymal sperm obtained from collared peccaries. In order to achieve better post-thawing sperm quality, we suggest that samples should be thawed at 37°C/60 s.

White-lipped peccaries (Tayassu pecari) and collared peccaries (Tayassu tajacu) are common ungulates of Amazonia that are integral to the ecosystem and are important sources of meat for local people. Information on the reproduction and productivity of peccaries is essential for implementing management practices that conserve peccary populations over short and long time-scales. This paper examines the reproductive biology of white-lipped and collared peccaries in the northeastern Peruvian Amazon in and around the Tamshiyacu-Tahuayo Community Reserve. Skulls and reproductive tracts of white-lipped and collared peccary were examined from hunted samples collected by local people, as part of a participatory wildlife management programme. In this Amazonian site both white-lipped and collared peccaries were in follicular and luteal stages year round. Similarly, conceptions, births and pregnancies were aseasonal for both species. Of white-lipped peccary females, 32.4% were pregnant (n = 219 adult females examined) compared with 46% of collared peccary females (n = 89 adult females examined). Overall, gross productivity was 0.53 foetuses/adult female for white-lipped peccaries and 0.89 foetuses/adult female for collared peccaries. Gross fecundity (number of female young produced/number of adult females) was 0.26 for white-lipped peccaries and 0.37 for collared peccaries. The estimated parturition–conception interval was 250 days (192–331 at the 90% confidence interval) for white-lipped peccaries and 129 days (80–205 at the 90% confidence interval) for collared peccaries. This study shows that reproductive productivity of white-lipped peccary is lower than collared peccary in the northeastern Peruvian Amazon. This difference in reproductive productivity has implications for management strategies, and suggests that white-lipped peccaries are more susceptible to the effects of hunting than collared peccaries.