Proteins in oocytes from calves and adult cows before maturation: relationship with their development capacity

― In order to improve the culture of oocytes that remain in an immature stage, the protein content before maturation and developmental ability of different groups of oocytes were investigated. The oocytes were classified according to source (adult or calf), the size of the follicle and the cumulus aspect. The influence of cumulus cells on developmental capacities was also analyzed and their protein patterns differ from those obtained with oocytes. The protein patterns differ specifically at 140 kDa and also at 143, 137, 60, 58, 52 and 27 kDa between oocytes from different sources, as does their capacity to develop into morula. Following in vitro maturation and fertilization, the oocytes were evaluated for percentage embryo development to the morula stage after 5 d. For cows' ovaries, denuded oocytes and oocytes with a defective cumulus had a percentage development of 2 and 12%, respectively. Cow ovary oocytes that were selected for cumulus compactness of 1-3 mm and > 3 mm had a percentage development of 21 and 25%, respectively. Oocytes from calf follicles had 0% development. These results indicate that the source of oocyte is a major determinant of its developmental capacity. bovine / in vitro oocyte maturation / protein / developmental competence Rsum ― Protines des ovocytes de veaux et de vaches adultes avant maturation : rapport avec leur capacit de dveloppement. Dans le but d'amliorer la culture des ovocytes demeurant un stage immature, des comparaisons du contenu protique avant maturation et la capacit de dveloppement de diffrents groupes d'ovocytes ont t analyses. Les ovocytes ont t classs selon la source (veau ou adulte), la grosseur du follicule et laspect du cumulus. L9nfluence des cellules de cumulus sur la capacit de dveloppement a galement t tudie et des diffrences en protines ont t observes entre ces cellules et les ovocytes. Les patrons protiques diffrent spcifiquement 140 kDa mais aussi 143, 137, 60, 58, 52 et 27 kDa entre les groupes d'ovocytes tout comme leurs capacits de dveloppement en morula. Suite une maturation et une fcondation in vitro, les ovocytes provenant d'ovaires de vache : i) dnuds, ii) non slectionns, iii) slectionns selon l'aspect du cumulus des follicules de 1-3 mm, iv) > 3 mm et des ovocytes aspirs des follicules de veaux donnent un pourcentage de dvloppement au stade morula valu j5 de : 2, 12, 21, 25 et 0% respectivement. Ces rsultats corroborent le fait que la source des ovocytes est dterminante de leur capacit de dveloppement bovin lmaturation ovocytaire in vitro / protines / capacit de dveloppement t