Developmental competence of antral follicles and their oocytes after gonadotrophin treatment of sows with gene polymorphisms for leptin and melanocortin receptors (Iberian pig).

PURPOSE

To evaluate possible differences in follicle and oocyte developmental competence after gonadotrophin treatment in sows of obese and lean genotypes.

METHODS

Follicle dynamics, ovulation rate and oocyte developmental competence to embryo were compared between females, of obese (n = 7) and lean genotypes (n = 10), treated with 1,250 I.U. of eCG and 500 I.U. of hCG.

RESULTS

The obese genotype showed lower numbers of follicles growing to preovulatory stages (12.4 ± 1.8 vs 18.6 ± 1.0, P < 0.05), of corpora lutea (16.0 ± 0.9 vs 23.5 ± 0.9, P < 0.05), and of recovered oocytes/embryos (8.0 ± 1.3 vs 12.9 ± 0.9, P < 0.05). Thereafter, embryo viability rates also decreased when compared to lean genotypes (62.5 vs 77.6%, P < 0.05).

DISCUSSION

To our knowledge, this is the first study analyzing the effect of obese genotypes on the ovarian response to exogenous gonadotrophins in a non-rodent animal model, the pig. A lower efficiency of gonadotrophin treatments for stimulation of follicle development and induction of ovulation was observed.