Efeito da suplementação oral do óleo de arroz na congelabilidade do sêmen ovino

Abstract

The aim was to carry out a bibliographic study about the sperm and the influence of reactive oxygen species (ROS) and antioxidant therapies on ram semen cryopreservation, as wel as evaluated experimentally the effects of supplementary feeding with commercial rice oil in ram semen freezability. For the latter purpose, were used 16 crossbred sheep, with a mean weight of 35 kg and average age of 15 months, previously evaluated clinical and andrologicaly. These animals were divided into two groups according to the quality of semen, where the control group included animals with approved seminal parameters, and the treatment group for individuals with lower semen quality. The animals from treatment group were supplemented daily, by oral way, with 100 mL per day commercial rice oil (Horse Range), during 63 days. In turn, animals in the control group received 100 mL of saline solution daily, by oral way, during the same period. Semen and blood samples were obtained by artificial vagina and jugular venipuncture, respectively, at wich 21 days, where the first sample was taken immediately before treatment start (day zero D0). Semen from each breeder was subjectively evaluated and individually processed for freezing (-196 oC), while from the blood was recovered the serum, which was stored under freezing (- 4 oC). After thawing, the semen was evaluated for sperm kinematics in the computerized system (CASA), as well as for plasma membrane and acrosomal integrity in a flow cytometry. The blood serum was used for testosterone determination by electrochemiluminescence. At D0, total (MT) and progressive (MP) motility, VCL, VAP and VSL were higher (P<0.05) in control than in the treatment group. On the other hand, after 21 days of treatment (D21), VCL, VAP and VSL from treatment group were higher (P<0.05) than the control group. Similarly, after 63 days of treatment the MP, VCL, VAP, VSL and total sperm with intact acrosome were higher (P<0.05) in the treatment than in the control group. Furthermore, according comparison of each group over time, was observed that while the seminal parameters from control group decrease throughout the study (P<0.05), those from treatment group are increase (P <0.05). There was no significant difference (P> 0.05 ) between the experimental groups with respect to serum testosterone concentration, regardless of evaluation time. Thus, it is concluded that oral administration of rice oil acts positively on the kinematics parameters and acrosomal integrity of ram semen subjected to cryopreservation, and that it not influence the plasma levels of testosterone.