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.