DNA methylation changes play essential roles in regulating the activities of genes involved in immune responses. Understanding of variable DNA methylation linked to immune responses may contribute to identifying biologically promising epigenetic markers for pathogenesis of diseases. Here, we generated genome-wide DNA methylation and transcriptomic profiles of six pairs of polyinosinic-polycytidylic acid-treated pig peripheral blood mononuclear cell (PBMC) samples and corresponding controls using methylated DNA immunoprecipitation sequencing and RNA sequencing. Comparative methylome analyses identified 5,827 differentially methylated regions and 615 genes showing differential expression between the two groups. Integrative analyses revealed inverse associations between DNA methylation around transcriptional start site and gene expression levels. Furthermore, 70 differentially methylated and expressed genes were identified such as TNFRSF9, IDO1 and EBI3. Functional annotation revealed the enriched categories including positive regulation of immune system process and regulation of leukocyte activation. These findings demonstrated DNA methylation changes occurring in immune responses of PBMCs to poly I:C stimulation and a subset of genes potentially regulated by DNA methylation in the immune responses. The PBMC DNA methylome provides an epigenetic overview of this physiological system in response to viral infection, and we expect it to constitute a valuable resource for future epigenetic epidemiology studies in pigs.

Integrin are adhesion molecules involved in uterine-conceptus interactions during the perimplantation period. In this study, the expression of alphaV and beta3 integrin subunits in endometrium during implantation in pigs was investigated. The immunohistochemical location was performed on paraformaldehyde-fixed, paraffin-embedded tissue sections, and the mRNA expression of alphaV was detected in endometrium. In addition, serum levels of estradiol, progesterone, follicle-stimulating hormone, and luteinizing hormone were measured on Days 0, 12, 18, and 25 of pregnancy. The results indicate that endometrium expressed integrin alphaV and beta3 in all stages examined. The most intensive staining for integrin alphaV and beta3 was observed in endometrial stroma in porcine pregnancy on Day 18. The mRNA of alphaV integrin strongly expressed on Day 18, and moderately expressed on Days 12 and 25. The correlation between serum hormone level and the mRNA expression of alphaV integrin was not significant. The expression patterns of integrin alphaV and beta3 during implantation provide insights into the important physiological function of alphaVbeta3 integrin in pig, and the strong expression of integrin alphaV and beta3 in mid-implantation may indicate its crucial role in successful implantation and embryo survival.

Abstract. The polymorphisms of ESR1, FSHB and RBP4 genes were detected by PCR-SSCP, PCR and PCR-RFLP in a Large White and a Landrace herd in Beijing, China and the influence of ESR1, FSHB and RBP4 on litter size traits was analyzed using three models. We found polymorphisms for the three genes in Large White besides for ESR1 and RBP4 genes in Landrace. The results showed that the most genotype effects are of ESR1 among these three genes.

There is accumulating evidence that leptin may be directly involved in mammalian reproduction, however, the potential role of obesity gene/obesity gene long form receptor (ob/ob-Rb) system in porcine implantation is poorly understood. To further confirm this role, mRNA and protein expression of ob/ob-Rb in implantation site and inter-implantation sites of porcine uterus on pregnancy day 13, 18 and 24 were compared in this study. Ob mRNA level went up with the advance of pregnancy and was higher in implantation site than inter-implantation site (P < 0.05). But ob-Rb mRNA, which was negative-regulated by leptin, went down with the advance of pregnancy and lessened in implantation site compared with inter-implantation site (P < 0.05). During the three implantation phase, leptin protein peaked at day 18 pregnancy (P < 0.05) and leptin protein at implantation site were always higher than inter-implantation site (P < 0.05). The higher ob-Rb protein in implantation site compared with inter-implantation site (P < 0.05) only appeared at day 18 pregnancy. Localization of ob/ob-Rb protein in porcine uterus was assayed using immunohistochemistry and found that ob/ob-Rb protein mainly located in luminal epithelium and glandular epithelium in pregnant pigs, but distinct immune-staining of leptin also detected in stroma in non-pregnancy porcine uterus except for luminal epithelium and glandular epithelium. In conclusion, the peak of leptin and the peak of ob-Rb protein in implantation site specifically appeared on day 18 pregnancy of pig. Another funning discovery is ob-Rb mRNA in porcine endometrium was mainly negative-regulated by leptin. The space-time difference of gene and protein expression for ob/ob-Rb confirmed ob/ob-Rb system role as delicate regulator of porcine implantation process.

DNA polymorphism of the porcine leukemia inhibitory factory (LIF) was investigated and used to study the effects on litter size in Large White pigs. A total of 2,167 litter records from 420 sows genotyped at two SNP loci (LIF1 and LIF2) within LIF gene were analyzed to determine whether LIF influenced total number born (TNB) and number born alive (NBA). The results indicated that B allele at LIF1 locus and A allele at LIF2 locus seem to have advantageous effects on litter size. However, the combined analyzed results demonstrated that genotype AAAA, ABBB, and BBBB are better than genotype AAAB, AABB, and ABAB for TNB and NBA in either third to eighth parity or all parities. In all parities, the sows with AAAA genotype had an advantage of 1.76 piglets (P < 0.001) for TNB and 1.44 piglets (P < 0.01) for NBA per litter over the AAAB sows, respectively. The results in this study demonstrated that LIF gene was significantly associated with litter size in pigs.

The objective of the present study was to explore associations between five microsatellites linked to Fec B and FecX I genes and litter size in Small Tail Han sheep. The polymorphisms of five microsatellite loci, OarAE101, BM1329, BMS2508, TGLA54 and TGLA68 were detected in 244 ewes of Small Tail Han sheep. Analysis of association between three microsatellite loci (BMS2508, BM1329 and OarAE101) located in the 10 cM region covering the Fec B gene (Booroola gene) and litter size in Small Tail Han sheep indicated that BMS2508 had significant effect on litter size in the second parity (p<0.05), but no significant effect on litter size in the first parity (p>0.05), while the other two microsatellite loci had no significant effect on litter size in both the first and the second parity in Small Tail Han sheep (p>0.05). At microsatellite locus BMS2508, least squares means in the second parity of genotypes 101/111 and 99/109 were significantly higher than those of genotypes 99/99, 99/101, 99/111 and 99/115 (p<0.05); least squares mean in the second parity of genotype 101/111 was significantly higher than that of genotypes 109/111 and 111/111 (p<0.05). Results of this study also indicated that two microsatellite loci (TGLA54 and TGLA68) that confined the 28.7 cM region covering the FecX I gene (Inverdale gene) did not affect litter size in both the first and the second parity in Small Tail Han sheep significantly (p>0.05). The information found in the present study is very important for improving the reproductive performance in sheep breeds by marker assisted selection.

This study examined the effects of nicotinamide on proliferation, differentiation, and energy metabolism in a primary culture of bovine adipocytes. After treatment of cells with 100-500 μM nicotinamide, cell growth was measured using 3-(4,5dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), and cellular lipid content was assessed by Oil Red O staining and a triglyceride (TG) assay. Several factors related to energy metabolism, namely adenosine triphosphatase (ATPase) activity, nitric oxide (NO) content, nitric oxide synthase (NOS) activity, the number of mitochondria and the relative expression of glyceraldehydes-3phosphate dehydrogenase (GAPDH), peroxisome proliferator-activated receptor-γ (PPARγ) and inducible NOS (iNOS), were also investigated. Results showed that nicotinamide induced both proliferation and differentiation in bovine preadipocytes. Nicotinamide decreased NO production by inhibiting NOS activity and iNOS mRNA expression, and controlled lipolytic activity by increasing ATPase activity and the number of mitochondria. The present study provides further evidence of the effects of nicotinamide on lipid and energy metabolism, and suggests that nicotinamide may play an important role in the development of bovine adipose tissue in vivo. This emphasizes the importance of investigating bovine adipose tissue to improve our understanding of dairy cow physiology.

A missense variant of the porcine melanorcortin-4 receptor gene (MC4R) is associated with fatness and growthrelated traits in pigs. The single nucleotide change of MC4R gene can be identified by TaqI PCR-RFLP. We checked the variation in nine Chinese native pig breeds, four pig breeds from France, together with a F2 population originating from a cross between Landrace and Lantang. We also analyzed the relationship of MC4R genotypes with effects on variation in growth and carcass-related traits in the F2 population of 111 animals. We found superiority of BB individuals for several related traits, such as age at 100kg weight, average backfat, etc. The results implicated the potential use of MC4R gene as a new genetic marker for the control of economically important growth and carcass traits in pigs.