The aim of the present experiment was to study the effect of fish oil and Vitamin E rich diets on semen production, sperm functions and composition in broiler breeders. The following parameters were measured: semen volume and concentration, sperm motility and viability, sperm susceptibility to induced peroxidation, sperm lipid and a-tocopherol contents. Dietary n - 3 PUFA were successfully transferred into spermatozoan phospholipid by fish oil feeding according to the following main features: (a) the C22:6n - 3 and C22:5n - 3 contents were increased, but C22:4n - 6 remained the peculiar and major polyunsaturate; (b) the content and proportion of total PUFA did not change; (c) the proportional increase of n - 3 PUFA was compensated by the decrease of n - 6 PUFA, an increase in the proportion of n - 9 fatty acids was also found. The sperm content of alpha-tocopherol was doubled increasing the dietary availability of the vitamin to 300 mg/kg of feed. The specific n - 3 PUFA and Vitamin E enrichment of chicken sperm affected cell functions. Significant interactions between the two treatments were also found for some parameters. The best sperm quality condition in control sperm (rich mainly in n - 6 PUFA) was found supplying 200 mg Vitamin E/kg of feed to the male breeders, and in contrast in n - 3 rich sperm supplying 300 mg Vitamin E/kg. (c) 2006 Elsevier Inc. All rights reserved.