35 The effect of fatty acid-free BSA supplementation on the ability of low-temperature-preserved chicken semen

Abstract

The dilution of chicken semen is one of the important processes for low-temperature storage and cryopreservation and is considered to be a highly applicable method for semen exchanges between small farms in developing countries. However, studies on chicken semen preservation have been limited for several reasons. First, dilution shocks chicken semen, with more than 4 to 6 times deterioration of sperm qualities. For example, approximately 8 to 10 times dilution reduces the activity and vitality of chicken semen. The dilution factor of chicken semen could not compete with that of mammals such as cow, ram, and goat. Second, the use of glycerol as a cryoprotectant causes serious problems such as infertility of spermatozoa; therefore, farmers are reluctant to use cryopreserved semen. To increase dilution factors of chicken semen without loss of fertility, the use of fatty acid-free BSA (FAF-BSA) in Beltsville poultry semen extender (BPSE) diluent was studied with Leghorn semen. In this study, fresh semen of 9 leghorn cocks was obtained using the side collection method. The semen was diluted 10 times using BPSE medium supplemented with 0.1% FAF-BSA as a final concentration and preserved at 17°C to test fertility and hatchability of diluted chicken semen. The semen was stored at 17°C for 6 h to test transportation time and used for AI to 18 layers with 3 repeats. After AI with 100 µL of preserved semen (total: 60~120 × 106 spermatozoa), the fertilized eggs were harvested for 10 days and incubated at 37.8°C for 21 days. The fertility of the eggs was confirmed at 5 days and the hatchability was confirmed at 21 days of incubation. The supplementation of FAF-BSA in dilution medium induced higher fertility rates (53.2% v. 38.3%; P < 0.05), and hatching rates also increased (90.9% v. 78.33%; P < 0.05) compared with the control group. All data were analysed by Student’s t-test. These results showed that FAF-BSA supplementation could improve semen utilisation by low-temperature preservation. Small farmers who want to increase the ability of their herd could utilise FAF-BAS containing diluents to exchange the semen.