Association between ESR1 and RBP4 genes and litter size traits in a hyperprolific line of Landrace × Large White cross sows

This study was aimed at analysing single-nucleotide polymorphisms in the oestrogen receptor 1 (ESR1) and retinol-binding protein 4 (RBP4) genes in a hyperprolific line of Landrace × Large White (Topigs 20) cross sows (n = 101). The following litter size traits were analysed: total number born, number of born alive and number of weaned piglets. ESR1 and RBP4 genotypes determined on the basis of single-nucleotide polymorphisms were analysed using the least square method with the GLM procedure in SAS with eight effects. The REG procedure was used to calculate the effects of the additive and dominance components. The second parity sows with ESR1 BB genotype had a significantly higher (P < 0.05) number of weaned piglets compared to AB, with a tendency towards difference (P < 0.1) between homozygotes for number of born alive and number of weaned piglets. In the case of the RBP4 gene, the first parity sows of the AA genotype had a significantly higher total number born (P < 0.05) compared with the BB genotype, with a tendency towards difference (P < 0.1) between AA and heterozygotes for total number born, and homozygotes for number of born alive. The BB genotype showed a tendency for higher number of weaned piglets (P < 0.1) as compared with the AA genotype in the third parity sows for the RBP4 gene. In all parities, significant effects (P < 0.05) of parity were recorded for total number born, number of born alive and number of weaned piglets, season of farrowing for total number born, and the ESR1 and RBP4 interaction for number of born alive. In the first parity sows, significant effects (P < 0.05) on total number born were determined for gene interaction and gestation length, the latter also being recorded in the second parity sows. The additive (a) effect of single-nucleotide polymorphisms in RBP4 was significant (P < 0.05) for total number born in all parities as well as in the first parity sows, and dominance effect (d) (P < 0.05) of single-nucleotide polymorphisms in ESR1 for number of weaned piglets in the third parity sows. The obtained results regarding the investigated genes could help to provide a better understanding of the effect of single-nucleotide polymorphisms on litter size and thus promote genetic progress in pig reproduction management.

Association of RBP4 Genotype with Phenotypic Reproductive Traits of Sows

PCR-RFLP was applied to a commercial crossbred pig population in order to investigate the association between polymorphism (SNP) of Retinol-binding protein 4 (RBP4) gene and reproductive performance. 400 sows were genotyped and 2000 records of reproductive traits were used in order to retrieve information about the allele frequencies and the association of the RBP4 gene with main reproductive characteristics of the population. A deviation from the Hardy-Weinberg equilibrium was observed as a result of the AB genotype excess. In addition, the AA genotype saw statistically significant higher values of (i) the total number of born piglets (p<0.05), (ii) the number of piglets born alive (p<0.01), and (iii) the number of weaned piglets (p<0.01). The number of the mummified piglets and the number of the piglets born dead did not differ between the various RBP4 genotypes. Interestingly, the AA genotype had a negative impact (p<0.05) on the number of piglets born dead, resulting indirectly in a larger litter size. In conclusion, the AA genotype and in extension the A allele of RBP4 gene are in favor of producing larger litter size, suggesting that the RBP4 gene may be used in Marker-Assisted Selection (MAS) programs for a rapid improvement of the reproductive characteristics in pigs.

RBP4 Gene Variants Are Associated with Insulin Resistance in Women with Previous Gestational Diabetes

Objective. This study aimed to examine possible genetic effects of some retinol binding protein-4 (RBP4) single nucleotide polymorphisms (SNPs) on the risk of gestational diabetes mellitus (GDM). In addition, the SNPs were examined for their possible association with insulin resistance at 6 weeks after delivery.Methods. This was a prospective study of 100 women with GDM and 100 participants with normal gestation who were evaluated at gestational week 30 and 6 weeks postpartum. Three SNPs of RBP4 (rs3758539, rs116736522, and rs34571439) were genotyped using TaqMan assay. The genotype distributions between GDM patients and normal controls were analyzed using logistic regression models. In addition, differences in clinical characteristics among subjects grouped by genotype were assessed using the analysis of covariance test.Results. The frequencies of the rare alleles were not significantly different between GDM patients and controls. However, we identified two variants rs3758539 and rs34571439 associated with insulin levels and insulin resistance in women with previous GDM.Conclusion. Noncoding SNPs of the RBP4 gene are not associated with GDM, but two SNPs showed associations with insulin resistance and insulin levels in women with prior GDM. Additional studies with increased sample size will be necessary in other GDM cohorts.