Swine semen cooled at 5ºC with PIGPEL-5 extender: effects on semen quality in vitro and fertility estimators in vivo

Abstract

This study consisted of two experiments. In Experiment 1, in vitro semen quality was assessed by comparing swine semen conditioned with either PIGPEL-5 extender at 5ºC or BTS extender at 17°C. Sperm motility was similar (P > 0.05) at 24 and 48 h post-dilution for PIGPEL-5 (67.9% and 59.3%, respectively) and BTS (73.9% and 64.0%, respectively). The frequency of sperm vigor equal to 4 was higher for PIGPEL-5 (P < 0.05) than for BTS after 24 h (70.8% and 29.2%, respectively) and 48 h (87.9% and 12.1%, respectively). After a thermal stress test, the frequencies of sperm vigor equal to 3 and 4 were higher (P < 0.05) for PIGPEL-5 than for BTS in both periods, but motility was not different between extenders (P > 0.05) in any period. Acrosome integrity was lower (P < 0.05) for PIGPEL-5 than for BTS in both periods, but head and tail morphology did not differ (P > 0.05). In the hypoosmotic swelling test, the frequency of tail rolling or bending was higher (P < 0.05) for BTS than for PIGPEL-5 after 24 h (33.1% and 8.2%, respectively) and 48 h (24.3% and 7.2%, respectively). In Experiment 2, 60 pre-pubertal gilts were artificially inseminated following induction of ovulation and using semen conditioned with both extenders (n = 30, per extender). There was no difference (P > 0.05) in the number of recovered or fertilized oocytes or in the fertilization rate for BTS (6.6 ± 0.6, 6.0 ± 0.6, and 83.7% ± 4.4, respectively) and for PIGPEL-5 (4.6 ± 0.9, 4.3 ± 0.8, and 87.3% ± 6.3, respectively). These results indicate that the PIGPEL-5 extender can be used to condition swine semen at 5ºC because parameters of semen quality and in vivo fertility following its use were generally similar to those of a conventional extender at 17°C.