Ovulation rate, embryo mortality and intrauterine growth retardation in obese swine with gene polymorphisms for leptin and melanocortin receptors

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

“…The evidences found in the present study would support the hypothesis of a possible deficiency in final maturation of preovulatory follicles and their oocytes in obese pigs [28]; as also found in obese humans [14,30] and dietinduced obese mice [31]. Both in humans and other mammals, the oocyte acquires gradually the ability to mature, be fertilized and finally to develop into a viable embryo, throughout final stages of folliculogenesis [32].…”

“…Ovulation rate after gonadotrophin stimulation was lower in the Iberian than in the LWxL sows; possible causes may be related to a lower intrinsic prolificacy of the Mediterranean genotype [20,27,28] but also, as supported by current and previous data [29], by a lower ovulatory efficiency of the follicles stimulated to grow by the exogenous gonadotrophins. Thereafter, most of the indexes of oocyte/embryo developmental competence (excepting fertilization rate) were higher in LWxL than in Iberian sows.…”

Sex and Breed-Dependent Organ Development and Metabolic Responses in Foetuses from Lean and Obese/Leptin Resistant Swine

“…Regressing corpora lutea were white opaque, smaller in size than normal corpora lutea and scarcely vascularised, as previously described [10]. Samples of two normal corpora lutea from each ovary were used for in vitro culture and determination of progesterone secretion.…”

“…IUGR in lean pigs is mainly due to intrauterine crowding and subsequent placental insufficiency in high-prolific lines [21]–[23]. Information on the occurrence of IUGR in obese breeds is scarcer than in lean swine, but previous studies in obese Iberian pigs provide strong evidence of a high incidence of IUGR occurring from very early-pregnancy stages [10], [24], in spite of a low prolificacy. Piglets affected by IUGR have high rates of mortality and morbidity at early postnatal stages.…”

Placentation, maternal–fetal interface, and conceptus loss in swine

“…With fertilization rates close to 95% [5][6][7][8], the number early embryos can potentially reach around 20. However, by the time of farrowing, litter size is reduced down to 10 to 13 piglets/sow [9].…”