Adição de ácido clorogênico e vitamina E ao sêmen suíno resfriado processado ou não com Percoll

Abstract

Percoll is a substance used to select spermatic sub-populations with better morphologic traits. However, negative effects can occur due to the action of reactive oxygen species, impairing the quality of the cooled semen. Thus, we aimed at verifying if the addition of vitamin E (tocopherol) or chlorogenic acid to the dilution mediums improves the quality of cooled swine semen processed in Percoll. The experimental design was in randomized blocks (ejaculates) in a 2x3 factorial scheme (with and without Percoll and in three antioxidant systems: control – no addition, chlorogenic acid and Vitamin E), totalizing six treatments and 12 replicates of each ejaculate. The chlorogenic acid and Vitamin E were added in the doses of 4.5 mg/mL and 400 µg/ml of dilutor, respectively. At 0, 48 and 72 hours of storage and 15 o C, the inseminating doses of 80 mL, containing 2.0 billion spermatozoa, were submitted to centrifuge protocol with Percoll for later evaluation. The use of Percoll impaired (P<0.01) all motility standards, however, reduced (P<0.01) total spermatic change in all storage periods. Both Vitamin E and chlorogenic acid improved (P<0.05) total motility after processing with Percoll, but only for the semen stored for 48 hours. The same effect was not verified (P>0.05) when the semen was stored for 72 hours. The chlorogenic acid improved (P<0.05) total motility for semen stored for 72 hours, but this effect was not verified (P>0.05) when the semen was processed in Percoll. The antioxidants did not influence (P>0.05) the feasibility and integrity of the acrosome, however, chlorogenic acid reduced (P<0.05) the total of morphologic changes to the fresh semen (0 hours), while Vitamin E increased the number of abnormal cells in the semen stored for 72 hours, regardless of the use of Percoll. There was no effect (P<0.05) of the antioxidants and Percoll over the concentration of malondialdehyde in the seminal plasma. The use of Percoll did not influence (P>0.05) the efflux of cholesterol in the semen, however, the chlorogenic acid increase the efflux in the fresh semen processed in Percoll and reduced this efflux in the semen stored for 72 hours not processed with Percoll. In conclusion, the addition of chlorogenic acid and Vitamin E to the dilutor medium improves the quality of the swine semen regardless of the use of the spermatic selection technique in Percoll. However, the benefits are not sufficient to maintain seminal quality after using the technique.