Effect of recombinant bovine somatoropin (rbST)‎ on sement physical characteristics and some biochemical constituents in seminal plasma of friesian bulls

الملخص EN

To investigate the effects of recombinant bovine somaotropin (rbST) on semen quality and some parameters in seminal plasma of bulls, six Friesian bulls (17.5 to 21.5 month old) were divided into two groups each of three bulls.

One group was injected with a dose of 500 mg of rbST every 14 days for eight injections, while the other group received saline soluation 0.9% NaCl in similar regim.

Two successive semen ejaculates were collected twice weekly for 16 weeks (no= 192 ejaculates), to determine the physical characteristics, in addition to intial fructose and methylene blue reduction test.

Field results of conception rate were used as an additional overall criterion of semen quality.

The obtained results revealed that rbST injection improved semen quality.

Ejaculate volume was inceased by 29% and mass motility was active by 34.6%, in case of rbST treated bulls.

The percentage of abonormal sperm was decreased by 25% and sperm cell concentration was increased by 44% in rbST treated bulls and so increased the total number of spermatozoa in ejaculates by 87%.

Concentrations of AST and ALT enzymes in seminal plasma were higher in rbST treated bulls by 15.3 and 15.9 %, respectively.

Semen of rbST treated bulls had lower methylene blue reduction time (10.5 vs.

20.9 min), higher intitial fructose (411.6 vs.

298.8 mg / 100) and higher conception rate (64 vs.

36 5%).

Bulls treated with rbST had higher (P < 0.05) plasma testosterone (61%), which seems to parallel to improve semen quality.

The present results indicate a possible beneficial use of exogenous rbST for improving bulls semen quality.