Effect of vitamin E on lipid peroxidation and fertility after artificial insemination with liquid-stored turkey semen

Turkey sperm plasma membranes contain high levels of polyunsaturated fatty acids that are susceptible to lipid peroxidation during in vitro storage at 4degreesC. Herein we assessed the degree of lipid peroxidation and fertility potential of semen liquid-stored for 24 h with the antioxidant vitamin E. Semen was collected weekly from 44 males and pooled as pairs (total = 22); the individuals in paired samples exhibited similar semen quality parameters. After initial semen evaluation, pooled samples were extended with Beltsville Poultry Semen Extender containing no supplement (control) or 10 or 40 mug/mL vitamin E and then stored at 4degreesC with constant aeration for 24 h. Lipid peroxidation was determined by measuring malonaldehyde (MDA) in aliquots (50 x 10(6) sperm) of fresh (0 h) and stored (24 h) semen. Sperm mobility was also evaluated. A total of 176 hens (8 hens/tom pair; 4 hens/0 h, 4 hens/24 h) were inseminated (150 x 10(6) sperm) weekly for 6 wk, and fertility was determined after 7 d of incubation. Initial MDA values of the 22 tom pairs ranged from 0.928 to 1.36 uM. Males varied in production of MDA during in vitro storage, with most pairs exhibiting a threefold increase. Results indicated that supplemental vitamin E did not reduce lipid peroxidation during liquid storage. Not surprisingly, artificial insemination with stored semen (with much higher MDA values) yielded lower fertility rates than control regardless of the presence of vitamin E. These results demonstrate that lipid peroxidation is a significant factor affecting the fertility of stored turkey sperm and that methods to prevent or reduce lipid peroxidation remain to be elucidated.