Addition of IGF-I to storage-cooled boar semen and its effect on sperm quality

ObjectiveTo evaluate in vitro IGF-I treatment during warming of storage-cooled boar semen and its effect on seminal quality parameters and metabolism in spermatic cells.DesignSemen samples (n = 7) warmed after stored at 15 °C for 24 or 72 h were divided into four equal parts. Different IGF-I concentrations (0, 50, 100 and 150 ng/mL) were added to the semen samples. The samples were incubated at 37 °C, and assessments were made after 0 and 120 min of incubation.ResultsFor semen samples that were stored for 24 h, the addition of IGF-I had no effect (p > 0.05) on the total motility and intensity of movements by spermatic cells, osmotic resistance, live:dead cell ratio or total spermatic abnormalities. However, incubation with 150 ng/mL IGF-I did decrease glutathione peroxidase activity (p < 0.05) and reduce lipid peroxidation after 120 min of incubation. For semen samples stored for 72 h and incubated with IGF-I for 120 min, there was a linear relationship between the IGF-I concentration and the live:dead ratio (p < 0.05). There was a quadratic relationship between the IGF-I concentration and both the osmotic resistance (peak results at IGF-I = 62.4 ng/mL) and glutathione peroxidase activity (peak results at IGF-I = 77.8 ng/mL). There was no effect on lipid peroxidation (p > 0.05) after 120 min of incubation. Addition of IGF-I also decreased fructose utilization by spermatic cells regardless of semen storage time (p < 0.05).ConclusionThis study suggests that IGF-I may be beneficial to semen stored for longer periods of time. Adding 150 ng/mL IGF-I improved the quality of semen stored for 24 h, and adding 78 ng/mL IGF-I improved the quality of semen stored for 72 h.