Fish sperm are particularly prone to suffer oxidative damage due to the high content in polyunsaturated fatty acids present in their membranes. Oxidative stress has been shown to reduce several spermatozoa functions, impairing sperm motility, cell viability and at later stage the DNA integrity. However, this oxidative stress can be counteracted by the antioxidant system present in spermatozoa and seminal plasma, and by a balance between anti-oxidative and pro-oxidative compounds. Antioxidants provided in the diet have a pivotal role in this balance and are special important during the periods of gametogenesis and spermiation. Several studies in different species demonstrated the beneficial effects of vitamins, minerals and other natural compounds in reducingthe production of reactive oxygen species (ROS) with a consequent improvement of sperm quality. Selenium and zinc are trace elements present in semen playing an important role in scavenging ROS. Both selenium and zinc are essential for the maintenance of germ cells and for the progression of spermatogenesis. Vitamins C and E reduce lipid peroxidation, and therefore, improve spermatozoa functions and integrity. There are no doubts about the effect of these compounds, but few studies have focus on the synergic properties of these substances in fish feeds and how they could modulate offspring quality. Therefore, in project SPERMANTIOX three sets of questions have been raised: 1-Can the antioxidant system be stimulated in the gilthead seabream germline through dietary antioxidant modulation? If so, what is the antioxidant combination that provide better protection to oxidative stress? 2-Are exosomal microRNAs (miRNAs) in seminal plasma useful as markers of the dietary-oxidative protection in fish sperm? If so, can they be used to characterize sperm quality as new biomarkers? 3-Do antioxidants in the diet induce modifications on sperm epigenome with putative transgenerational effects? If so, does sperm exosomal miRNAs working as a fingerprint mechanism, transmissible to the progeny can influence offspring quality?