Fig. 1
Definition of reproductive age in zebrafish. (A) Serum estradiol levels in female and male zebrafish during ageing. Data are reported as meanąs.d. Final sample number=12 per sex/age. (B) Application of the ovary maturation classification in the evaluation of the effects of ageing on zebrafish ovarian tissue (see supplementary material Fig. S1 for details). Three sections from five fish per subgroup were analyzed. Data were expressed as meanąs.d. H&E-stained (C,E) and PAS-stained (D,F) sections of the ovaries of young (4mpf) and old (18mpf) female zebrafish. Atretic follicles (indicated by arrows) were mostly found in old female fish with low to absent E2 levels. mpf, months post fertilization.