Submitted to: BARC Poster Day
Publication Type: Abstract Only
Publication Acceptance Date: April 15, 2007
Publication Date: April 25, 2007
Citation: Bongalhardo, D.C., Long, J.A. 2007. Effects of genetics on quality and cryopreservation of semen from pedigreed chicken layer lines. BARC Poster Day. Technical Abstract: The fertility rates of cryopreserved poultry semen are highly variable and not reliable for use in commercial production or preservation of genetic stocks. The objective of the present work was to compare semen quality from 4 pedigreed layer lines (Lines 1, 2, 3, and 4) before and after freezing. A total of 80 roosters (20 males/line at 6 mths of age) were used as semen donors. Prior to cryopreservation, semen from each male was assessed for volume, sperm concentration, sperm motility (sperm mobility assay), sperm viability (SYBR-14/PI), ATP content and protein complement. Semen from each male was frozen individually as pellets using 6 % DMA as the cryoprotectant. For protein analysis, seminal plasma was removed from fresh and frozen/thawed semen. Protein from isolated sperm (5 roosters/line) was extracted, quantified, pooled by Line, and subjected to 2-D SDS-PAGE analysis. Lines significantly differed (p<0.05) in all characteristics analyzed. Line 1 had higher motility than Line 2-4, and presented one of the highest values of sperm concentration, viability, and ATP content; however Line1 had one of the lowest ejaculated volumes. For Line 1, concentration was correlated with viability (r=0.49, p<0.0394) and motility (r=-0.50, p<0.0366). In contrast, Line 4 had lower viability and higher volume than Lines 1-3. For Line 4 only, viability was correlated with motility (r=0.60, p<0.0110), ATP content (r=0.77, p<0.0003), and concentration (r=0.55, p<0.0219), while motility was correlated with ATP content (r=0.72, p<0.0010). In all Lines, there was a marked decrease in protein content after thawing (25.5 +/- 2.2, fresh sperm; 10.1 +/- 0.4 mg/ml frozen/thawed sperm; p<0.0001), and a noticeable reduction in the number of visible protein spots for frozen/thawed sperm compared to fresh sperm. These results demonstrate that there is variability in fresh semen characteristics among these pedigreed lines at 6 mths of age and that, during the cryopreservation process, the amount and type of sperm proteins are reduced. We plan to identify the protein complement in fresh and frozen/thawed sperm using mass spectrophotometry.