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Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 6/13/2003 Publication Date: 11/1/2003 Citation: Long, J.A., Kramer, M.H. 2003. Effect of vitamin e on lipid peroxidation and fertility after artificial insemination with liquid-stored turkey semen. Poultry Science. 82:1802-1807. Interpretive Summary: The turkey industry relies exclusively on artificial insemination for commercial production. Development of successful semen storage methods would provide the producers with greater flexibility in bird management, as well as save time and conserve financial resources. The purpose of this study was to examine the extent to which turkey semen is compromised by a deleterious cellular breakdown know as lipid peroxidation. Further, we attempted to reduce the amount of lipid peroxidation occurring during liquid storage by including vitamin E, an antioxidant naturally found in turkey semen, in the extender. The results demonstrated that lipid peroxidation is a significant factor affecting the reduced fertility of stored turkey semen, and that individual toms characteristically vary in the predisposition to form toxic peroxides during long-term storage. Extenders containing vitamin E have been marketed to commercial poultry producers, however, our data suggests that vitamin E as a sole supplement is not beneficial for improving the fertility of stored turkey semen. Technical Abstract: An experiment was conducted to assess the degree of lipid peroxidation in fresh ejaculates and after liquid storage of turkey semen, and if vitamin E would prevent formation of lipid peroxides. Semen was collected weekly from 44 males and pooled as pairs (total = 22); paired samples exhibited similar semen quality parameters. After initial evaluation (sperm concentration, viability, mobility), pooled samples were extended with Beltsville Poultry Semen Extender containing no supplement (control), 10 ug/ml VE or 40 ug/ml VE, and then stored at 4C with constant aeration (150 rpm orbital shaker) for 24h. Lipid peroxidation was determined by measuring malonaldehyde (MDA) in aliquots (50 million sperm) of fresh (0h) and stored (24h) semen. Similarly, sperm mobility was evaluated using the Sperm Mobility Assay. A total of 176 hens (8 hens/tom pair; 4 hens/0h, 4 hens/24h) were inseminated (150 million sperm/ml) weekly for 4 wks and fertility determined after 7 days of incubation. Initial MDA values of the 22 pairs ranged from 0.928¿1.36 uM. Additionally, males characteristically varied in the production of MDA, with some pairs exhibiting a 3-fold higher MDA after in vitro storage. Mean MDA values for control and vitamin E treatments indicated that supplemental vitamin E did not reduce lipid peroxidation during liquid storage. Not surprisingly, AI with stored semen yielded lower fertility rates than control regardless of the presence of vitamin E, and poor fertility was associated with MDA levels. It is clear from these results that lipid peroxidation is a significant factor affecting the fertility of stored turkey sperm, and that methods to prevent and/or reduce lipid peroxdation remain to be elucidated. |
