Regulation of winter wheat-originated antifreeze glycoprotein on rooster spermatozoa freezability

The freezability of chicken spermatozoa is low, therefore, effective cryoprotectants is desiderated. Antifreeze proteins (AFPs) are widely found in cold-tolerant species and help them to survive in freezing environments. This study was the first to evaluate the effects of different concentrations of plant-originated antifreeze glycoprotein (AFGP) (0, 0.1, 1, and 5 μg/mL) on post-thawed sperm motion characteristics, morphology, mitochondrial function, antioxidant activity, and fertilizing potential in chickens. Results showed that the total motility of 0.1 to 1 μg/mL AFGP groups were significantly higher than those of the 5 μg/mL AFGP group (P < 0.05). The post-thawed sperm viability of 0.1 μg/mL AFGP group was significantly higher than any of test groups (P < 0.05). Higher abnormal morphology rate of post-thawed sperm was observed in the control group (0 μg/mL AFGP) than in the 0.1, 1, and 5 μg/mL AFGP groups (P < 0.05). The concentrations of malondialdehyde (MDA) decreased gradually with the increase of AFGP concentration. ATP was significantly higher in the 0.1 and 1 μg/mL AFGP groups than those of control and any of test groups (P < 0.05). The 0.1 to 1 μg/mL AFGP groups had increased mitochondrial membrane potential (MMP) level (P > 0.05). The 0.1 μg/mL AFGP group had the highest average fertility (61.36%) compared with control group (57.02%) and any of test groups of chickens at 31 wk of age, and the 1 μg/mL AFGP group had the highest average fertility (37.72%) compared with control group (21.73%) and any of test groups of chickens at 65 wk of age. In conclusion, the results from this study suggest lower concentration of AFGP (0.1–1 μg/mL) showed positive effect for sperm function. This study inspires the continuous evaluation and seeking right way of adopting different kinds of AFPs in rooster semen cryopreservation.