Boar semen proteome : functional implications during storage

Artificial insemination (AI) with extended semen offers many benefits to the swine industry through improving biosecurity and access to high-quality genetic material. Modern boar industry worldwide is based on the use of AI of sows with extended cooled semen at 15 – 20 °C for 1 – 5 days [1]. However, semen preservation has also many negative effects on spermatozoa which are related to dilution, change of microenvironment, chilling and ageing [2]. Boar semen in particular is specially sensitive to cold shock in comparison to other animals [3], which seems to be related to the low cholesterol/phospholipid ratio of cell membrane [4]. For this reason it is of high scientific relevance the study of sperm cells physiology during room temperature storage in a sensitive model such as boar semen. This model of study could also be applied to evaluate the putative additives useful to improve sperm fertility after storage [5]. Fresh and 3 days stored semen were analysed through 2DE/Maldi TOF. Results highlighted several differentially expressed proteins. Among them ATP citrate lyase was found to be upregulated and Chaperonin containing TCP 1, sub 5 and citosolic non specific dipeptidase were found to be downregulated. Oxidative stress during long term sperm cells storage in one of the major reasons of cells death because of the progressive depletion of fatty acids for cellular structures [5]. Cellular response to counteract this lack is the increased synthesis of fatty acids by enzymes such as ATP citrate lyase as documented from our results.