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Developmental capacity in vitro of prepubertal oocytes
G A Palma1, D J Tortonese, F Sinowatz
1Department of Animal Production, INTA, Balcarce, Argentina. gpalma@balcarce.inta.gov.ar
Anatomia, Histologia, Embryologia
|November 2, 2001
Summary
Oocyte quality and yield from immature Simmental calves are lower for in vitro fertilization (IVF) programs compared to mature cows. However, supplementing maturation media with higher concentrations of follicle-stimulating hormone (FSH) can improve developmental potential in calf oocytes.
Area of Science:
- Reproductive biology and biotechnology
- Animal science and veterinary medicine
Background:
- Investigating the efficiency of in vitro fertilization (IVF) programs using oocytes from immature animals is crucial for improving assisted reproductive technologies.
- Ovary and follicle size, along with oocyte quality, are key determinants of success in mammalian oocyte maturation and embryonic development.
Purpose of the Study:
- To compare the ovary size, follicle size, and oocyte quality of 3-month-old Simmental calves with those of sexually mature females.
- To evaluate the efficiency of using calf ovaries in an IVF program.
- To determine the effects of varying concentrations of follicle-stimulating hormone (FSH) and oestradiol-17beta (E-17beta) on the in vitro maturation and development of calf oocytes.
Main Methods:
- A 2-year comparative study involving 3-month-old Simmental calves and sexually mature cows.
- Oocytes were collected and assessed for quality, and their developmental potential in vitro was evaluated.
- Maturation media were supplemented with different concentrations of FSH and E-17beta to assess their impact on oocyte development to morula and blastocyst stages.
Main Results:
- Smaller ovary size in calves was significantly correlated with lower oocyte recovery rates and reduced quality of cumulus oocyte complexes.
- Calf oocytes exhibited significantly lower rates of cleavage and blastocyst formation compared to oocytes from mature females.
- Maturation media supplemented with higher FSH concentrations (20 µg/ml or 10 µg/ml) plus 2 µg/ml E-17beta improved cleavage and blastocyst development rates in calf oocytes, while high E-17beta concentrations (4 µg/ml) negatively impacted development.
Conclusions:
- The proportion and developmental competence of oocytes from immature Simmental calves are lower than those from mature cows, potentially decreasing the overall efficiency of IVF programs.
- Supplementation with higher concentrations of FSH in maturation media can enhance the maturation and developmental capacity of oocytes from prepubertal calves.
- Optimizing maturation media composition is essential for maximizing the utility of oocytes from immature animals in assisted reproduction.