Immunization against GnRH in the male camel (Camelus dromedarius): effects on
sexual behavior, testicular volume, semen characteristics and serum testosterone
concentrations.
Author(s): Ghoneim IM, Waheed MM, Al-Eknah MM, El-Bahr SM.
Affiliation(s): Department of Clinical Studies, College of Veterinary Medicine and Animal
Resources, King Faisal University, Al Ahsa 31982, Kingdom of Saudi Arabia.
Publication date & source: 2012, Theriogenology. , 78(5):1102-9
The effect of immunization against gonadotrophin releasing hormone (GnRH) on
sexual behavior, total scrotal size, semen characteristics and serum
concentrations of testosterone, was evaluated for 24 wks in sexually mature
camels (Camelus dromedarius). Eight bull camels were randomly divided into a
treatment and control group. Four male camels were immunized using 2 mg GnRH -
tandem-dimer conjugated to ovalbumin, (Pepscan Systems, the Netherlands)
administered subcutaneously, 4 wks apart. Control male camels received the same
amount of saline solution. Significant decline in serum testosterone level was
observed in three immunized camels out of four, whereas one camel showed no
effect. The testosterone levels reached to <1.0 ng/mL serum by week 4 after
booster injection and remained suppressed through the course of the study. The
total testicular volume was not affected until the end of the experiment. In
treated animals, the sexual behavior negatively affected after the booster
injection. Anti-GnRH vaccine had a seriously detrimental effect on the acrosin
amidase activity and normal acrosome percentages in treated male camels. It is
concluded that the vaccine was effective in reducing serum testosterone levels
and libido, and it had a serious harmful effect on the acrosin amidase activity
and percentages of spermatozoa with normal acrosome. The immunogen did not affect
the total testicular volume.
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