Glutathione Peroxidase 5 Is Expressed by the Entire Pig Male Genital Tract and Once in the Seminal Plasma Contributes to Sperm Survival and In Vivo Fertility
Glutathione peroxidase 5 (GPX5) is an H2O2 scavenging enzyme identified in boar seminal plasma (SP) This study attempted to clarify its origin and role on sperm survival and fertility after artificial insemination (AI) GPX5 was expressed (Western blot and immunocytochemistry using a rabbit primary polyclonal antibody) in testes, epididymis and accessory sex glands (6 boars) SP GPX5 concentration differed among boars (11 boars, P 0.001) among ejaculates within boar (44 ejaculates, P 0.001) and among portions within ejaculate (15 ejaculates) The first 10 mL of the sperm rich fraction (SRF, sperm peak portion) had a significantly lower concentration (8.87 0.78 ng/mL) than the rest of the SRF and the post SRF (11.66 0.79 and 12.37 0.79 ng/mL, respectively, P 0.005) Sperm motility of liquid stored semen AI doses (n 44, at 15 17degC during 72h) declined faster in AI doses with low concentrations of SP GPX5 compared to those with high levels. Boars (n 11) with high SP GPX5 showed higher farrowing rates and litter sizes than those with low SP GPX5 (a total of 5,275 inseminated sows) In sum, GPX5 is widely expressed in the boar genital tract and its variable presence in SP shows a positive relationship with sperm quality and fertility outcomes of liquid stored semen AI doses.
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