Spermatozoa from some boars can be frozen more successfully than others. In this study, a two dimensional-differential in gel electrophoresis (2D-DIGE) was used to analyze the total protein contents (proteome) of fertile boar spermatozoa known as “poor freezers” or “good freezers” (Table 1).

Freshly collected semen of eight boars was pooled, while their frozen-thawed counterparts were mixed according to their freezability status (i.e., four poor freezers or four good freezers). A total of 2,213 protein spots were detected with high confidence in all groups of semen samples — fresh, poor freezers, good freezers (Table 2).

Analyses revealed qualitative and quantitative differences between groups of samples, which indicated damaging effects of cryopreservation on sperm proteins when compared to fresh sperm samples.

Most importantly, both freezer groups differed not only from each other but also individually from fresh semen. This study indicates that biomarkers could be developed as an aid in identifying biomarkers of cryo-tolerant sperm. In turn, these prescreened sires could be used more strategically and efficiently.

Researchers: Jean M. Feugang, Mark A. Crenshaw, Scott T. Willard and Peter L. Ryan, Mississippi State University, Mississippi State, MS, and Terry Emerson, Prestage Farms, West Point, MS. Contact Feugang by phone (662) 325-7567 or e-mail jn181@ads.msstate.edu.