Investigating the need for antibiotic supplementation to the extender used for semen cryopreservation in collared peccaries

Abstract

The objective was to investigate the effects of semen freezing extender supplementation with antibiotics on bacterial load of semen samples, sperm functional and morphological metrics in the collared peccary. Fresh ejaculates from 10 males were extended in Tris-egg yolk-glycerol supplemented or not (control) with gentamicin (70 μg/mL) streptomycin-penicillin (SP; 1 mg/mL−1000 IU/mL) or and cryopreserved in liquid nitrogen. Bacterial load, sperm motility patterns, morphology, membrane functionality and integrity, mitochondrial activity, chromatin integrity and sperm-binding ability were evaluated in fresh and frozen-thawed samples. Regardless of the use of antibiotics, the sole cryopreservation provoked a significant decrease (P < 0.05) in bacterial load compared to fresh samples (from average values > 1 x 106 CFU/mL to <0.4 × 106 CFU/mL). Post-thawing sperm kinetic parameters were not affected by the absence or presence of different antibiotics, except for beat cross frequency that was significantly (P < 0.05) impaired by SP supplementation compared to the group without antibiotics. After thawing, sperm morphology, membrane functionality and integrity, and mitochondrial activity were also not affected by the presence or absence of antibiotics; however, a significant decrease was observed in the group without antibiotics (P < 0.05) in comparison to fresh samples. Regarding sperm-binding ability, there were no differences among the different groups. While collared peccary semen could be efficiently cryopreserved in the absence of antibiotics in the extender, the use of both gentamicin or the streptomycin-penicillin combination is recommended as effective antibiotic supplementation for a further control of bacterial loads without affecting sperm parameters.

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

“…In general, the data obtained in the present work are similar to the results obtained previously in the freezing of collared peccary semen, also without the use of antioxidants in the diluent (Moreira et al., 2022, 2023). Regarding ROS analysis, however, only recently another study presented the evaluation of this parameter for fresh semen using the same methodology described here (Santos et al., 2023).…”

“…For freezing, the samples were diluted and cryopreserved in Tris containing egg yolk (20%), glycerol (3%) and gentamicin (70 μg/mL) (Moreira et al., 2022) and destined for the following treatments: (A) control (without antioxidant), (B) 200 IU/mL CAT (C) 400 IU/mL CAT, (D) 150 IU/mL SOD, (E) 300 IU/mL SOD and (F) combination of 200 IU/mL CAT and 150 IU/mL SOD. The samples were frozen following a rapid freezing curve previously described by Silva et al.…”

“…For freezing, the samples were diluted and cryopreserved in Tris containing egg yolk (20%), glycerol (3%) and gentamicin (70 μg/mL) (Moreira et al, 2022) and destined for the following treatments:…”

“…In this sense, different efforts were conducted to better understand the physiological aspects of collared peccary semen (Peixoto et al., 2012), and to improve cryopreservation protocols that enable the formation of a biobank (Moreira et al., 2023). Bearing in mind that the fluid from the accessory glands of the genital tract can play an important role in semen freezeability (Moreira et al., 2022), different aspects of collared peccary seminal plasma were deciphered, such as the identification of small amounts of superoxide dismutase (SOD), while catalase (CAT) was not found in such fluid (Santos et al., 2018).…”