Boar spermatozoa and prostaglandin F 2α: Quality of boar sperm after the addition of prostaglandin F 2α to the short-term extender over cooling time

Abstract

Prostaglandin F 2α (PGF 2α) has been used to improve reproductive performance in swine. The goal of the present work was to determine how the addition of PGF 2α affects boar sperm quality. Eleven different treatments were evaluated: eight with only PGF 2α (0.625, 1.25, 2.50, 5, 10, 12.50, 25 and 50 mg PGF 2α/100 ml) and three binary treatments (0.625 mg PGF 2α/100 ml + 200 μg/ml hyaluronic acid (HA), 1.25 mg PGF 2α/100 ml + 200 μg/ml HA, 0.625 mg PGF 2α/100 ml + 7.5 μM caffeine (Caf)). All these substances were added to 16 ejaculates from 16 healthy and sexually mature boars ( n = 16), and each ejaculate was considered as a replicate. Our study also assessed the effects of these 11 treatments over different periods of preservation. Sperm quality was tested immediately after the addition of treatments (time 0), and after 1, 3, 6 and 10 days of cooling at 15 °C. To evaluate sperm quality, five parameters were analysed: (1) sperm viability, acrosome and mitochondrial sheath integrity (using a multiple fluorochrome-staining test), (2) sperm motility, (3) sperm morphology and (4) agglutination (using a computer assisted system) and (5) osmotic resistance (using the ORT). Parametric (analysis of variance for repeated measures) and non-parametric tests (Friedman test) were used as statistical analyses. Treatments with PGF 2α concentrations higher than 12.5 mg/100 ml were cytotoxic while the others did not damage boar spermatozoa. Thus, the other treatments may be used to produce profitable effects without adverse effects. Moreover, the addition of PGF 2α at 5 mg/100 ml to sperm diluted in BTS may maintain sperm viability and motility better after 6 days of cooling, because significant differences were observed ( P < 0.05) compared with control at the same time.