The combined genotypes effect of ESR and FSHβ genes on litter size traits in five different pig breeds

Evaluation of candidate genes related to litter traits in Indian pig breeds

Improvement in litter traits is the key to profitable pig farming that directly enhances the economic standing of the farmers in developing countries. The present study aimed to explore oestrogen receptor (ESR), epidermal growth factor (EGF), follicle-stimulating hormone beta subunit (FSHβ), prolactin receptor (PRLR) and retinol-binding protein 4 (RBP4) genes as possible candidate genetic markers for litter traits in indigenous pigs of India. The breeds included in the study were Ghungroo, Mali, Niang Megha and Tenyi Vo, and the reproductive traits considered were litter size at birth (LSB), number born alive (NBA), litter weight at birth (LWB), litter size at weaning (LSW) and litter weight at weaning (LWW) at their first parity. PCR-RFLP and primer-based mutation detection methods were used to identify polymorphism, and associations between the genotypes and the traits were analysed using a general linear model. The Ghungroo pigs recorded the best litter performances among the breeds (p < .05, LWB p < .01). Different alleles and genotypes of the genes under study were detected. Short interspersed nuclear element (SINE) -/- genotype of FSHβ revealed significantly higher litter traits (p < .05, LSB p < .01). The LWW was also found to be significantly influenced by ESR BB and AB, EGF AB and BB, and PRLR CC genotypes (p < .05). Although we did not find statistically significant and consistently superior litter traits with respect to different genotypes of other studied genes than genotype SINE -/- of the FSHβ, PRLR CC genotype demonstrated superior performances for all the litter traits. Our study revealed the FSHβ as a potential candidate genetic marker for litter traits in indigenous pig breeds of India.

Genetic effect and combined genotype effect of ESR, FSHβ, CTNNAL1 and miR-27a loci on litter size in a Large White population

To select new Large White line with high number of piglets born, genotypes of estrogen receptor (ESR), the follicle stimulating hormone β subunit (FSHβ), catenin alpha like 1 (CTNNAL1) and miR-27a were tested in 472 Large White sows. The associations of different genotypes with litter size traits were also studied. The results showed ESR^BB and FSHβ^BB sows produced 0.41-1.49 more pigs per litter (p < .05) for total number born (TNB) and number born alive (NBA) than did other corresponding genotypes. TNB of CTNNAL1^CG sows is 0.50 more pigs per litter (p < .05) than that of CTNNAL1^GG sows with the dominance effect of 0.25 pigs per litter (p < .05). miR-27a^BB sows had a less estimated breeding value (EBV) to TNB and had a more number of mummified pigs (NM) than did miR-27a^AA or miR-27a^AB sows (p < .05). Therefore, ESR^B, FSHβ^B, CTNNAL1^G, miR-27a^A allele was favorable for litter size traits. Furthermore, combined genetic effect analysis showed ESR^AAFSHβ^BB, ESR^AACTNNAL1^CG, ESR^AAmiR-27a^AA, FSHβ^BBCTNNAL1^CC, FSHβ^BBmiR-27a^AA and CTNNAL1^CG miR-27a^AB was the favorable combined genotype for litter size traits. These results identified favorable alleles and genotypes for litter size traits and suggested a potential selection scheme for litter size in Large White pigs.

Systematic Analysis of Long Non-Coding RNAs and mRNAs in the Ovaries of Duroc Pigs During Different Follicular Stages Using RNA Sequencing

The dynamic process involving the selection and maturation of follicles is regulated and controlled by a highly synchronized and exquisitely timed cascade of gene expression. Studies have shown that long non-coding RNA (lncRNA) is essential for the normal maintenance of animal reproductive function and has an important regulatory function in ovarian development and hormone secretion. In this study, a total of 2076 lncRNAs (1362 known lncRNAs and 714 new lncRNAs) and 25,491 mRNAs were identified in libraries constructed from Duroc ovaries on days 0, 2 and 4 of follicle development. lncRNAs were shorter, had fewer exons, exhibited a shorter ORF (Open Reading Frame) length and lower expression levels, and were less conserved than mRNAs. Furthermore, 1694 transcripts (140 lncRNAs and 1554 mRNAs) were found to be differentially expressed in pairwise comparisons. A total of 6945 co-localized mRNAs were detected in cis in 2076 lncRNAs. The most enriched GO (Gene Ontology) terms were related to developmental processes. KEGG (Kyoto Encyclopedia of Genes and Genomes) pathway analysis revealed that the differentially expressed lncRNAs targeted mRNAs, and the differentially expressed mRNAs were related to the TGF-β signaling pathway, the PI3K-Akt signaling pathway, the Retinol metabolic pathway and the Wnt signaling pathway. This study deepened our understanding of the genetic basis and molecular mechanisms of follicular development in pigs.

Impact of theESRgene on litter size and production traits in Czech Large White pigs

To evaluate the effect of the PvuII polymorphism of the oestrogen receptor gene on litter size and production traits in Czech Large White swine, data from 1250 sows and 3600 litters were analysed with two four-trait animal models. The traits in the first model were number of piglets born alive in a sow's first litter, number of piglets born alive in second and subsequent litters, lifetime daily gain and lean meat percentage. The second model included number of piglets born, number of piglets born alive, number of piglets weaned and litter weight at weaning from first and subsequent litters. The oestrogen receptor (ESR) locus significantly affected prolicacy in the first parity and averaged over all parities (P < 0.05), with allele A superior to allele B. In the first parity, AA sows produced approximately 0.5 more live piglets per litter than BB sows. Averaged over all parities, this difference was c. 0.25 piglets. Results for total number of piglets born and number of piglets weaned were similar to results for numbers born alive. No significant dominance effect was found for prolificacy traits. For litter weight at weaning, no significant additive effect was observed at the ESR locus, but a significant negative dominance effect (-1.5 kg) was estimated averaged across parities (litters of AB sows were similar to litters of BB sows for this trait). No pleiotropic effect of the ESR polymorphism on average daily gain or lean meat percentage was found.