Comparison of In Vitro Maturation, In Vitro Fertilization, Metabolism and Ultrastructure of Oocytes from Prepubertal and Adult Pigs

Contents In vitro maturation and fertilization, metabolism and ultrastructure were examined for oocytes from prepubertal and adult pigs. The proportion of oocytes undergoing in vitro maturation was lower for oocytes derived from prepubertal (piglets aged 8–10 weeks; 59.8% and gilts aged 5–6 months; 79.2%) than for those from adult ( ows aged 4–6 years; 92.2%) pigs (p < 0.05). A higher proportion of oocytes from piglets (22.8%) degenerated during in vitro maturation than from gilts (4.8%) and adult pigs (4.7%; p < 0.05). There was an increased incidence of polyspermic fertilization in prepubertal (piglet; 52.2%, gilt; 23.8%) compared with adult (7.1%) oocytes (p < 0.05). There were no differences in the metabolism of glucose, glutamine or pyruvate between oocytes from prepubertal and adult pigs. The metabolism of glutamine by prepubertal and adult oocytes matured in vitro was significantly higher than that by prepubertal oocytes matured in vivo (p < 0.05). Oocyte size and ultrastructure was also similar for oocytes from prepubertal and adult pigs. These data show that prepubertal and adult pig oocytes have a different in vitro developmental capacity, but similar metabolic activity and ultrastructure, under the conditions investigated.