Effect of different concentrations of tris royal jelly-enriched extender on cooled and post-thawed bull semen \

الملخص EN

Preservation of semen by cooling or freezing causes structural and functional damage of spermatozoa.

Exogenous antioxidants are added to semen extender to counteract this damage and enhance its preservability.

This study was designed to evaluate effect of adding various concentrations of Royal jelly (RJ) to tris-extender on bull semen characteristics after cooling and post-freezing.

Pooled bull semen was extended with tris-citrate-fructose egg yolk diluent+7% glycerol (control: 0% Royal jelly) and various concentrations of Royal jelly (RJ1: 0.05%, RJ2: 0.1%, RJ3: 0.2%, RJ4: 0.3%).

Extended semen was subjected to slow cooling for 4 hrs, followed by freezing.

Cooled and post-thawed semen was assessed for semen quality parameters.

Additionally, post-thawed semen was used for artificial insemination to assess its field fertility.

Sperm viability of cooled semen was superior in the first group (0.05%).

Membrane integrity (HOST percentage) was significantly higher (P<0.05) in the RJ2- RJ4 group (0.1and 0.3%).

Acrosome integrity was best in RJ1- RJ2 (0.05 and 0.1%).

Percentage of sperm motility and abnormalities did not show significant difference among groups of cooled semen.

Motility, sperm viability, and acrosome integrity of post-thawed semen was superior in in RJ1-RJ2 (0.05 and 0.1%) relative to other groups.

Also, membrane integrity was superior in the RJ1 (0.05%) compared to other concentrations.

Conception rate was the best in RJ1and RJ2 (69.6 & 66.6% respectively).

Conclusions: Addition of RJ to bull semen extender improved its quality during cooling and post-thawing, also enhanced conception rate upon artificial insemination.

The use of wider range of RJ concentrations is to be considered for future studies to define the optimum dose