Sperm quality and oxidative stress in cryopreserved semen from Nelore bulls of different ages

The aim of this study was to analyze the follicle and oocytes morphometry from different follicular classes. The ovaries of 17 queens in anestrus were classified into three groups: Young (0–1 year), Adults (1–6 years) and Older (>6 years). The ovaries were fixed in paraformaldehyde 5%, embedding in paraffin and staining with haematoxylin-eosin. For morphological analysis the tissue sections were photographed by microscope (Olympus BX61) and classified as primordial, unilaminar primary, multilaminar primary, secondary and pre-ovulatory follicles. A total of 1039 follicles were measured and the parameters utilized were: diameter (lm), area (lm2) and perimeter (lm). The statistical used were ANOVA and the means were compared by Tukey test and medians using the Kruskal-Wallis test followed by Dunn’s multiple comparisons (p < 0.05). In young queens primordial follicles there were increased in the mean diameter, area and perimeter of follicle (45.16 lm, 1941 lm and 157.24 lm) and oocytes (40.55 lm, 1320.4 lm and 129.90 lm) when compared to adults (Follicles: 41.51 lm, 1652.4 lm e 145.56 lm and in oocytes: 37.57 lm, 1134.3 lm and 120.58 lm). A biphasic pattern of follicle and oocyte growth was observed through linear regression. Before antrum formation, follicle (x) and oocyte (y) size were positively and linearly correlated (y = 0.304x + 25.01, r = 0.72), although after antrum formation a negative correlation were found (y = 0.007x + 98.00, r = 0.00). The queen offers many benefits as a model of ovarian folliculogenesis, and may be useful in preserving of endangered animals. Acknowledgements: FAPESP for financial support.