Comparison of Viability, ATP and In vitro Fertilization of Boar Sperm Stored at 4℃ in the Three Different Diluents

This study was designed to develop a method of liquid storage of boar sperm at $4^{\circ}C$ by using the modified Beltsville F5 (BF5) diluent with bovine serum albumin (BSA) and N-acetyl-D-glucosamine. Boar sperm were stored in lactose-egg yolk and N-acetyl-D-glucosamine (LEN), BF5 and Golden-Pig liquid 4 (GPL4) diluents at $4^{\circ}C$ for 5 days and were examined for sperm viability, adenosine triphosphate (ATP) and in vitro fertilization (IVF). The percentage of sperm viability in GPL4 diluent was higher than in LEN and BF5 diluent from 1 to 5 days of storage at $4^{\circ}C$. The percentage of sperm viability steadily declined from 1 to 5 days of storage in the three different diluents. Sperm ATP in GPL4 diluent was higher than in LEN and BF5 diluents from 1 to 5 days of storage. Sperm ATP rapidly declined after 5 days of storage in the three different diluents. Porcine oocytes matured in vitro were inseminated with different sperm concentrations of liquid semen stored for 3 days in GPL4 diluent. The percentage of monospermic oocytes did not show any differences from 2.5 to $20{\times}10^5$ sperm/ml. However, the percentage of polyspermic oocytes in the sperm concentration of $2.5{\times}10^5$ sperm/ml was lower than in concentrations of 5, 10 and $20{\times}10^5$5 sperm/ml. The percentage of blastocysts from the cleaved oocytes at $2.5{\times}10^5/ml$ sperm concentration was significantly lower than at 5, 10 and $20{\times}10^5sperm/ml$ concentrations. In conclusion, GPL4 diluent can be stored at $4^{\circ}C$ for 5 days and showed higher sperm viability and sperm ATP concentration compared with LEN and BF5 diluents. Also, we found that GPL4 diluent can be used for IVF of porcine oocytes.