Cryopreservation of collared peccary (Pecari tajacu) semen using different freezing curves, straw sizes, and thawing rates

AbstractThe objective of this study was to verify the effect of different freezing curves, straw sizes, and thawing rates on the cryopreservation of collared peccary semen. Twelve ejaculates were obtained from captive adult males by electroejaculation, and evaluated for sperm motility, kinetic rating, viability, morphology, and functional membrane integrity. The ejaculates were diluted in a coconut water extender (ACP-116c) with egg yolk and glycerol, packaged into 0.25mL or 0.50mL plastic straws and cryopreserved in liquid nitrogen following a slow (−10°C/min) or a fast (−40°C/min) freezing curve. After one week, samples were thawed at 37°C/1min or 70°C/8s and evaluated as reported for fresh semen, and also for kinematic parameters (computerized analysis). A significant decrease in sperm motility and kinetic rating was observed after glycerol addition at 5°C and also after thawing for all the treatments (P<0.05). Regarding post-thaw semen variables, no differences were verified between freezing curves when the same straw size and thawing rate were taken as reference (P>0.05). In general, values for sperm characteristics found after thawing at 37°C were better preserved than at 70°C (P<0.05), both in the use of 0.25mL or 0.50mL straws, which were similar for semen packaging (P>0.05). The evaluation of the kinematic parameters of sperm motility confirmed these results at values varying from 20% to 30% motile sperm for the samples thawed at 37°C, and values fewer than 12% motile sperm for samples thawed at 70°C (P<0.05). In conclusion, we recommend the use of a fast freezing curve that reduces the time spent on the cryopreservation of collared peccary semen, which could be packaged both in 0.25mL or 0.50mL straws, but the thawing should be conducted at 37°C/1min

Establishing the hypoosmotic swelling test for sperm analysis in collared peccaries (Pecari tajacu)

Soluções hiposmóticas com diferentes concentrações (0, 50, 100, 150, 200mOsm/L) foram testadas para a avaliação funcional da membrana espermática de catetos (n=13). Foi verificado que o número de espermatozoides reagidos diminuía (P<0,05) de acordo com o aumento da osmolaridade do meio. A maior porcentagem (71,8%) de espermatozoides reagidos, bem como a menor variação nas respostas osmóticas, foi detectada com o uso de água destilada (0mOsm/L) (P<0,05), a qual também apresentou a menor variação nos resultados, de acordo com os erros padrão verificados. Em conclusão, a água destilada aparenta ser uma solução adequada para o uso no teste hiposmótico para sêmen de catetos

Morphology and vascularization of the corpus luteum of peccaries (Pecari tajacu, Linnaeus, 1758) throughout the estrous cycle

The current paper characterizes the changes in morphology and vascularization of the corpus luteum of collared peccaries during the estrous cycle and correlates progesterone synthesis (P4). Twenty females were subjected to a treatment for estrus synchronization; an ear implant containing 1.5 mg of norgestomet was implanted on D0, whereas on D9 the peccaries received an IM injection of eCG 200UI and 50g of PGF2a. The animals were divided into four groups (G1, G2, G3 and G4) and euthanized on post-ovulation days 3, 12, 18 and 22. The ovaries were collected and the corpora lutea were measured and processed for histological and vascular density (Dv). Blood was collected for dosage of P4 serum. The morphology of the ovaries, the corpora lutea and P4 varied significantly during the estrous cycle (P<0.001). There was a significant co-relationship between weight and length of the ovaries and CL (r = 0.66, r = 0.52, P<0.05, respectively) and between weight, length and width of the CL and P4 (r = 0.51, r = 0.54 and r = 0.68, P<0.05, respectively). The luteal Dv was highly influenced by the estrous cycle phase (P<0.0001). The P4 and luteal Dv concentrations were higher in G2 and evidenced maximum secretory activity, with a highly significant correlation (P<0.0001). Assessed lutein parameters may estimate the phase of the estrous cycle in peccaries and the functional activity of the corpus luteum