... days in all ewes. Along with sponges withdrawal 400IU eCG (Intergonan, Intervet) was administered and two days later (d38) a second OPU was performed.
MELATONIN IMPROVES THE DEVELOPMENTAL COMPETENCE OF SHEEP OOCYTES
1 I ,
Valasi
1Dept
2 Th ,
1 Th ,
Tsiligianni Papanikolaou Dimitriadis Vainas E2, Samartzi F2, Amiridis GS1
1 I ,
of Vet Reprod & Obstetrics, Vet. Faculty, Karditsa, 2NAGREF Thessaloniki, GREECE
INTRODUCTION
Melatonin treatment has been shown to be an effective method for the advancement of seasonal breeding in anoestrous ewes, and that the fertility achieved is at least as good as that given by conventional progestogen-PMSG treatment. Previous studies demonstrated that exogenous melatonin and / or progestagen treatments promote follicular development and ovarian activity in anoestrous ewes. Moreover, it has been reported a positive effect of melatonin supplementation in culture media on in vitro embryonic development. However, the effect of melatonin treatment on oocytes’ quality and on in vitro developmental competence of collected oocytes is controversial. The objectives of this study were to evaluate the effects of melatonin treatment on follicular development before and after follicular aspiration and on developmental competence of collected oocytes,
MATERIALS AND METHODS
Fourteen adult ewes were allotted to two equal groups (M, C). During anestrus melatonin implants (Regulin, Ceva) were inserted (day 1) in ewes of group M.On day 14, in both groups laparoscopical follicular aspiration (OPU) of all visible follicles was performed. On day 22 intravaginal progestagen sponges (MAP, Veramix, Upjohn/Veterin) were inserted for 14 days in all ewes. Along with sponges withdrawal 400IU eCG (Intergonan, Intervet) was administered and two days later (d38) a second OPU was performed. The collected oocytes from the 2nd OPU were matured and fertilized in vitro. Statistical analysis Statistical analysis was performed by t-test and chi-square test. RESULTS At the 1st OPU the number of large follicles was greater in melatonin treated than in control ewes (mean±sd: 4.4±1.8 vs 1.8±1.5; p0.05) (Fig 1). At the 2nd OPU the quality of collected oocytes (grade A and B) was better in group C (87.5%) compared with M (42.9%). The fertilization rate was greater in group M (20/28, 71.4%) compared with C (6/21, 28.6%) (p
