Elevated dietary intake of Zn-methionate is associated with increased sperm DNA fragmentation in the boar

Boars fed on ration of 200 ppm Zn methionate showed a significant increase (P < 0.001) in sperm DNA fragmentation when compared to animals fed on non-supplemented and rations containing 150 ppm Zn methionate. There was a positive correlation (R2 = 0.207; P = 0.002) between % sperm DNA fragmentation (SDF) and the concentration of Zn in spermatozoa. Increased Zn in the diet also resulted in a non-proportional increase in Zn concentration in the testis and spermatozoa but not in the epididymis; Zn in sperm accumulated at levels up to 50 times higher than that found in the seminal plasma and 10–13 times that found in the epididymis and testis, respectively. These results show that supplementation of dietary Zn at a concentration of 200 ppm had an adverse effect on boar sperm DNA quality and may be related to the ability of spermatozoa to accumulate Zn during spermiogenesis.