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Patrick McCann
Masters Student
School School of Animal and Veterinary Sciences
Location Charles Sturt University, Wagga Wagga
Phone
03 52739312
Email patmccann@bigpond.com
Project
The effects of somatotropin and antioxidants on sperm functions
Summary
With artificial breeding, it is most important for stored and transported semen to retain its fertilising potential . The composition of the medium, or extender, used for semen dilution and storage has significant effects on sperm integrity, viability and longevity all of which influence the ability for the sperm to successfully fertilise an ovum.
Somatotropin (Growth Hormone) has been shown to be necessary for spermatogenesis and development of male reproductive function including cell differentiation, proliferation and metabolism. Studies have shown that somatotropin increases the percentage of motile spermatozoa without a reduction in the concentration of spermatozoa with normal morphology or changes in other semen characteristics. The action of somatotropin has been linked with that of insulin-like growth factor-I (IGF-I), both of which play a role in male reproductive functioning. Few studies have been done on the effect of the addition of somatotropin to semen extenders, with most studies concentrating on the addition of somatotropin either in feed or by injection.
Sperm has a high content of unsaturated fatty acids in their membranes, and they lack a significant cytoplasmic component containing antioxidants. Therefore, they are susceptible to lipid peroxidation by O 2 - and H 2 O 2 . Growing evidence suggests that the balance between the generation of reactive oxygen species (ROS) and their detoxification by antioxidants plays an important role in fertility in particular sperm capitation. The production of toxic reactive oxygen species, damaging sperm motility and viability has been shown to be involved in some of the steps of cryopreservation and prolonged in vitro incubation of semen. Lipid peroxidation by ROS during sperm preservation can be detrimental sperm viability due to a high content of unsaturated fatty acids and a low level of antioxidants in spermatozoa. The addition of catalase has been shown to improve the motility of spermatozoa when an imbalance of ROS occurs which can occur in the processing procedures used for IVF and AI with ensuing damage to sperm through the inactivation of proteins, DNA damage and peroxidation of unsaturated lipids.
The proposed study aims to investigate the effects of the addition of somatotropin and antioxidants to semen extenders on sperm functions (motility, longevity, membrane integrity, chromatin integrity) when added to normal
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