Ricinoleic acid esters from castor oil modifying male reproductive system of Amblyomma cajennense (Fabricius 1787)

Ticks of the genus Amblyomma have medical and veterinary importance because they can transmit pathogens to humans, as well as domestic, wild and livestock animals. The management and control of this tick has led livestock farmers to an inadequate use of synthetic chemical acaricides, consequently creating environmental problems and selecting resistant populations. Thus, the search for new substances that can be efficient in tick control and have low toxicity to the environment and non-target organisms is latent. Therefore, the present study aimed to evaluate the effect of ricinoleic acid esters from castor oil as modifying agents of A. cajennense male reproductive system, seeking an alternative method to control these parasites. Hence, esters from castor oil were incorporated to the diet of rabbits, which were then infested with A. cajennense. Male ticks were collected from the hosts and their reproductive systems were removed and prepared for histological and histochemical techniques. The results showed that the effects of esters became more evident at the highest concentration available, leading to morphophysiological changes in the secretory cells of the accessory gland complex, altering the secretion content and causing morphological changes in spermatids. The esters changed development dynamics and gamete production, probably affecting the production of spermatophores and seminal fluid. Our results confirmed that these substances have the potential to interfere with reproduction, one of the most important biological processes for a species