Research Note: Dietary supplementation with pyrroloquinoline quinone disodium (PQQ.Na(2)) improves oxidative status and semen quality in aging layer breeder roosters

As the antioxidant capacity of sperm declines with age in roosters, the objective of the present study was to determine the effects of different levels of pyrroloquinoline quinone disodium (PQQ.Na(2)) on antioxidative and sperm quality parameters of aging layer breeder roosters. A total of ninety-six 63-wk-old Jinghong No. 1 layer breeder roosters were randomly assigned to 4 treatments (0, 0.5, 1, 2 mg/kg PQQ.Na(2)) for 6 wk. Antioxidant activity and semen parameters were assessed biweekly. The dietary administration of PQQ.Na(2) significantly increased semen quality (semen volume, sperm motility, straightness, progressive motility, curvilinear velocity, straight-line velocity, and amplitude of lateral head displacement) and antioxidant capacity (T-SOD, GSH-Px, hydroxyl radical scavenging ability, and/or superoxide scavenging capacity) in seminal plasma in aging layer breeder roosters. Whereas, PQQ.Na(2) supplementations significantly decreased malondialdehyde (MDA) concentration in seminal plasma in aging layer breeder roosters. Supplementation with 1 mg/kg dietary PQQ.Na(2) as an antioxidant supplement could increase sperm quality and antioxidant activity of aging layer breeder roosters, while a higher dose (2 mg/kg) did not result in further increment.