Time filter

Source Type

Coslada, Spain

Torres-Rovira L.,INIA | Gonzalez-Anover P.,NUTEGA | Pallares P.,INIA | Perez-Solana M.L.,INIA | And 3 more authors.
Animal Production Science

The Mediterranean Iberian pigs show a clear predisposition to obesity, due to gene polymorphisms for leptin receptors, and a lower prolificacy when compared with lean breeds. Previous studies indicate a bimodal effect of obese genotypes on prolificacy; either by lowering ovulation rate or by increasing embryo losses when compared with lean genotypes. The present study aimed to discriminate the relative influence of both parameters by comparing strains of Iberian females with different prolificacy (14 original purebred Retinto, group R, and 20 Retinto × Torbiscal females selected for prolificacy, group RT). Examination of ovaries around Day 40 of pregnancy showed a higher ovulation rate in the RT than in the R sows (21.5 ± 1.4 versus 12.3 ± 1.0 corpora lutea, respectively; P < 0.0005). However, there was a higher incidence of implantation failures and early embryo losses in the RT females (42.9 versus 14% for the group R; P < 0.005). Thus, the number of viable embryos was higher in the RT line (10.8 ± 0.5 versus 7.6 ± 0.7 in the R sows, P < 0.0005), but also limited when compared with ovulation rate. Conversely, this effect was not found in the R sows; however, prolificacy of these females was limited by higher embryo mortality (24.1 versus 4.6% for RT females). In conclusion, the present study evidences dissimilar reproductive behaviour among strains of the Iberian pig differing in prolificacy and confirms previous evidences suggesting the existence of intrinsic factors avoiding excessively large litter sizes in Iberian females. © 2012 CSIRO. Source

Gonzalez-Anover P.,NUTEGA | Encinas T.,Complutense University of Madrid | Letelier C.A.,Austral University of Chile
General and Comparative Endocrinology

This study compares follicular function and ovulatory efficiency in 20 sows with obesity/leptin resistance genotype (Iberian pig) and 20 females of lean commercial crosses (Large White × Landrace; LW × L). Estrous cycle was synchronized with progestagens; ovulation was induced with eCG and hCG, in half of the females of each group, to determine its effect. In females of both breeds not treated with gonadotropins, the number of follicles larger than 4.9. mm and the estradiol secretion increased throughout the follicular phase (P< 0.05); estradiol values were similar at estrus detection (22.5 ± 1.2 vs. 26.5 ± 0.6. pg/ml respectively, for Iberian and LW × L sows). Moreover, ovulation rate was higher in Iberian pigs (15.3 ± 1.3 CLs) than in LW × L (10.2 ± 1.3 CLs; P< 0.05), with mean progesterone values being 18.1 ± 0.7. ng/ml in Iberian and 16.8 ± 0.6. ng/ml in LW × L pigs. Thus, the preovulatory follicular growth and the ovulatory efficiency seem not to be the main limiting factors for reproductive efficiency in Iberian swine. The gonadotropins induced a significant increase, when compared to untreated females (P< 0.05), in the number of follicles larger than 4.9. mm growing throughout the follicular phase; however, estradiol values at estrus were lower (P< 0.05) in both breeds (9.2 ± 0.7. pg/ml in Iberian vs. 8.6 ± 0.8. pg/ml in LW × L), when compared with the nontreated animals, which suggests defective follicular function after gonadotropin stimulation. There were also no differences between genotypes in ovulation rate (15.2 ± 1.3 vs. 12.7 ± 1.8) and progesterone secretion (21.2 ± 0.8. ng/ml in Iberian and 20.9 ± 0.7. ng/ml in LW × L sows) in the treated animals. In conclusion, the current findings indicate that preovulatory follicular growth and ovulatory efficiency are not main limiting factors for prolificacy in a pig model of leptin resistance and obesity. © 2010 Elsevier Inc. Source

Gonzalez-Bulnes A.,Instituto Nacional Of Investigaciones Agrarias Inia | Torres-Rovira L.,Instituto Nacional Of Investigaciones Agrarias Inia | Ovilo C.,Instituto Nacional Of Investigaciones Agrarias Inia | Astiz S.,Instituto Nacional Of Investigaciones Agrarias Inia | And 5 more authors.
General and Comparative Endocrinology

The current study was conducted in a swine breed (Iberian pig) with a genotype that predisposed the pig to obesity. The aim of the study was to determine the morphological, metabolomic and endocrine features of early conceptuses and to elucidate how placental gene expression (related to placentation, angiogenesis and fetal nutrition), maternal hormones and the metabolome affect the fetal environment and fetal growth. Conceptus viability and growth were found to be related to maternal endocrine (plasma progesterone levels) and metabolic features (plasma levels of leptin, cholesterol, HDL-c, LDL-c and triglycerides). These features were related to the placental expression of the vascular endothelial growth factor A (VEGFA) and leptin (LEP) genes, the placental efficiency and, thus, the nutrition and the metabolism of the fetus (availability of glucose, triglycerides and cholesterol, as HDL-c). Viability of conceptuses in females with evidence of dyslipidemia (low plasma levels of total cholesterol due to low HDL-c concentration but high levels of triglycerides) was diminished. The availability of nutrients and metabolic substrates to the conceptus was also affected in females with higher fat deposition and evidence of dyslipidemia. In conclusion, the conceptus viability and growth appear to be strongly related to maternal metabolic features and, thus, affected in females with alterations in lipid metabolism. © 2012 Elsevier Inc. Source

Gonzalez-Anover P.,NUTEGA | Encinas T.,Complutense University of Madrid | Torres-Rovira L.,INIA | Pallares P.,INIA | And 3 more authors.

The Mediterranean Iberian pigs are obese genotypes, due to a leptin resistance syndrome related to leptin receptor gene polymorphisms. The Iberian pig is affected by a lower prolificacy when compared to lean breeds, and thus may constitute a good animal model for adverse effects of obesity in reproductive performance. The present study determined possible differences in rates of ovulation and embryo implantation and later incidence of embryo mortality and intrauterine growth retardation (IUGR) in sows of Iberian breed (n = 23) and highly-prolific lean commercial crosses (Large White × Landrace, n = 17) at two critical periods of swine pregnancy: Day 21 (just after achievement of trophoblast attachment) and Day 35 (just after completion of the transition from late embryo to early foetal stage). Two different reproductive performances were identified in the Iberian breed; 58.3% of the females had lower ovulation rates than LWxL (13.2 ± 2.3 vs 22.5 ± 1.6, P < 0.05), but 41.7% had a similar number of ovulations (18.2 ± 3.9). However, those Iberian sows having high ovulatory rates showed a high incidence of regression of corpora lutea and embryo losses between Days 21 and 35, which was not found in Iberian females with low ovulation rates; therefore, the number of viable embryos was similar in both Iberian groups (8.2 ± 1.0 and 8.4 ± 1.0) and lower that in highly-prolific LWxL (14.8 ± 1.8, P < 0.05). At Day 35, a total of 167 conceptuses (73 LWxL and 94 IB) were evaluated for IUGR. The LWxL conceptuses were longer and wider than Iberian (69.5 ± 0.1 and 64.4 ± 0.1 vs 49.9 ± 0.1 and 41.9 ± 0.1 mm, P < 0.0001). However, Iberian conceptuses were heavier than LWxL (107.4 ± 6.6 vs 68.6 ± 2.4 g) due to a lower quantity of fluids and a higher development of the placental tissues in comparison to the embryo itself. In conclusion, current study indicates a bimodal effect of obese genotypes on reproductive performances, either by lowering ovulation rate or by increased embryo losses in the first third of pregnancy. © 2011 Elsevier Inc. Source

The effects of age and reproductive status on carbohydrate and lipid metabolism of Iberian sows reared in an intensive management system were examined. These animals, with age, are predisposed to hyperglycaemia and dyslipidemia which may develop in response to nutritional challenges during lactation. At weaning, high levels of glucose, triglycerides and low-density lipoproteins cholesterol (LDL-c) with low high-density lipoproteins cholesterol (HDL-c) are indicative of insulin resistance. Reproductive Biology 2011 11 2: 165-171. Source

Discover hidden collaborations