The immune profile induced by different adjuvants is essential on the effects over fertility, gonadal function, and hypothalamic GnRH-I expression in immunocastrated animals.

Canine immunocastration development has been of interest for many years as a complementary strategy to surgical castration. The purpose of this paper was to verify the effect of a recombinant vaccine for dog immunocastration. Two tests were done, one under controlled conditions and a second under field conditions. Animals were injected with 1 mL of 500 µg GnRXG/Q recombinant protein; 500 µg of low molecular weight chitosan as adjuvant; 1 mL NaCl 0.9% q.s. In the first trial, eight Beagle male dogs between the ages of 1 and 3 comprised the sample, randomly divided into two groups: vaccinated group (n = 7) and control group (n = 2). The second trial had 32 dogs with owners. In the first controlled conditions trial, the vaccine produced specific antibodies that remained until the end of the trial (day 270), inducing reduced testosterone and spermiogram changes in the immunized animals. In a second trial, on the field, specific immunity was induced, which remained high up to day 150. The vaccine also reduced sexual agonistic and marking behaviors. This new vaccine proved to be safe, immunogenic, capable of reducing gonadal functionality, and had a positive effect on inducing reduced sexual, agonistic, and marking behavior of the animals.