No abstract

Enhancing pig reproductive efficiency has the potential to have a significant positive economic impact on the pig business. We collected four reproduction records of 734 Yunong black pigs in this study, including the total number of piglets born (TNB), the number born alive (NBA), the average birth interval of piglets (ABI) and the average birth weight (ABW). A total of 453 Yunong black pigs were genotyped with Porcine 50K SNP BeadChip. Twenty-five SNPs and 35 genomic areas were found to have a substantial impact on the reproductive performance of Yunong black pigs by single-locus GWAS and single-step GWAS (ssGWAS). For the ssGWAS, we found that the two genomic regions (12.67-13.85 and 14.26-15.01 Mb) on Sus scrofa chromosome X were associated with TNB, NBA and ABI. It is worth noting that CNC10110530 and CNC100141254 significantly affected the TNB by both GWAS methods. Finally, we further determined the gene functions by enrichment analysis and a literature search, and identified 28 of them as candidate genes affecting the reproductive performance of Yunong black pigs, including RET, EIF1AX, NELL2, CTPS2, S100G, RBBP7 and PDHA1. This study further promotes understanding of the genetic mechanism of porcine reproductive performance, and also provides more molecular markers for pig breeding.

Yunong black pig is an indigenous black pig breed being cultivated that has a pure black whole body. However, some individuals appear with a white spot on the nose. We performed case–control association studies and FST approaches in 76 animals with nose color records (26 white‐nosed pigs vs. 50 black‐nosed pigs) by Illumina Porcine SNP50 BeadChip data. In total, 76 SNPs, which included 2 genome‐wide significant SNPs and 18 chromosome‐wide suggestive SNPs, were identified by association study. The top‐ranked 0.1% windows of FST results as signals under selection and 24 windows were selected. The lymphoid enhancer binding factor 1 was identified as candidate gene with strong signal in analyses of genome‐wide association study and FST in black‐ and white‐nosed pigs. Overall, our findings provide evidence that nose color is a heritable trait influenced by many loci. The results contribute to expand our understanding of pigmentation in pigs and provide SNP markers for skin color and related traits selection in Yunong black pigs. Additional research on the genetic link between nose pigmentation is needed.

Pig farming has an effect on farmers and the farm environment. Pig gut microbes play an important role in this effect. However, which microbial composition is more likely to be affected remains unknown. Primarily, we collected 136 samples in pig farm A, including 70 pig fecal, 18 farmers, 4 individuals without contact with any type of farm animal (“non-exposed” persons) fecal, and 44 environmental dust samples (dust from inside and outside pig houses and the farm). Another 43 samples were collected from pig farm B, including 10 pig fecal, 24 environment samples, and 9 humans fecal. Whereafter, 16S rRNA sequencing and taxonomic composition analysis were performed. Result showed that pig farmers significantly upregulated 13 genera compared with non-exposed persons, and 76 genera were significantly upregulated inside the pig house than outside the pig house. Comparing non-exposed persons who were farther away from the pig farm, the results showed that the relative abundance of three microbes, including Turicibacter, Terrisporobacter, and Clostridium_sensu_stricto_1, increased between the farmers and environment inside and outside the pig farm, and significant differences were observed (P < 0.05). Moreover, the abundance increased with the exposure time of farmer animals and spatial location to pigs. The greater the distance from the farm, the less effective the three microbes were. Although the distance is about 550 km, the analysis results of pig farm A and pig farm B confirm each other. This study shows that the three microbes where pig farmers co-occurring with the environment come from pig farms, which provides new ideas for blocking the transmission of microbial aerosols in pig farms and reducing pollution.