Simple sequence repeats (SSRs) are commonly used as molecular markers in research on genetic diversity and discrimination among taxa or breeds because polymorphisms in these regions contribute to gene function and phenotypically important traits. In this study, we investigated genome-wide characteristics, repeat units, and polymorphisms of SSRs using sequencing data from SSR-enriched libraries created from Wuzhishan (WZS), Bama (BM), inbred Luchuan (LC) and Zangxiang (ZX) miniature pig breeds. The numbers and types of SSRs, distributions of repeat units and polymorphic SSRs varied among the four breeds. Compared to the Duroc pig reference genome, 2518 polymorphic SSRs were unique and common to all four breeds and functional annotation revealed that they may affect the coding and regulatory regions of genes. Several examples, such as FGF23, MYF6, IGF1R, and LEPROT, are associated with growth and development in pigs. Three of the polymorphic SSRs were selected to confirm the polymorphism and the corresponding alleles through fluorescence polymerase chain reaction (PCR) and capillary electrophoresis. Together, this study provides useful insights into the discovery, characteristics and distribution of SSRs in four pig breeds. The polymorphic SSRs, especially those common and unique to all four pig breeds, might affect associated genes and play important roles in growth and development.

To study the differences in meat quality and nutritional components between the local Shanghai pig breeds Meishan pig (MS), Shawutou pig (SWT), Fengjing pig (FJ), and the commercial Duroc × Landrace × Yorkshire (DLY) crossbred pigs, and to provide data support for the selection and breeding of superior pig breeds, this study selected 30 piglets each of three local pig breeds and DLY with similar birth ages and weights around 25 kg, fed them the same daily ration with uniform nutritional components, and slaughtered ten of them at around 100 kg weight for evaluation of differences in meat quality indicators (primarily intramuscular fat content, tenderness value, texture, etc.) and amino acid content among the varieties. The results indicated significant differences among the four pig breeds in intramuscular fat content, with MS having the highest content and significant differences in tenderness value compared to the other three breeds (p < 0.05). In terms of texture indicators, MS and SWT differed significantly from FJ and DLY in terms of hardness and fracturability indicators (p < 0.05), with certain differences existing among the four breeds in other indicators. In amino acid content, the differences in total amino acid content among the three Shanghai local pig breeds were not significant (p > 0.05), but all were significantly higher than DLY. Further analysis revealed significant differences in amino acid content between Shanghai local pig breeds and DLY, with Shanghai local pigs showing markedly higher levels of serine, proline, isoleucine, leucine, and histidine compared to DLY (p < 0.05). Regarding nucleotides, the cytidine monophosphate (CMP) indicator of MS differed significantly from the other three breeds (p < 0.05), SWT’s uridine monophosphate (UMP) indicator differed significantly from FJ and DLY, and FJ and DLY’s inosine monophosphate (IMP) indicator was significantly higher than MS and SWT (p < 0.05), while SWT’s adenosine monophosphate (AMP) indicator was significantly higher than the other three breeds (p < 0.05). The results of this study suggest that the meat quality and nutritional composition of Shanghai local pigs are significantly superior to DLY, with MS exhibiting significantly better meat quality and nutrition compared to SWT and FJ among the three local pig breeds.

Asthma has been extensively studied in humans and animals, but the molecular mechanisms underlying asthma in Meishan pigs, a breed with distinct genetic and physiological characteristics, remain elusive. Understanding these mechanisms could provide insights into veterinary medicine and human asthma research. We investigated asthma pathogenesis in Meishan pigs through transcriptomic and metabolomic analyses of blood samples taken during autumn and winter. Asthma in Meishan pigs is related to inflammation, mitochondrial oxidative phosphorylation, and tricarboxylic acid (TCA) cycle disorders. Related genes include CXCL10, CCL8, CCL22, CCL21, OLR1, and ACKR1, while metabolites include succinic acid, riboflavin-5-phosphate, and fumaric acid. Transcriptomic sequencing was performed on panting and normal Meishan pigs, and differentially expressed genes underwent functional enrichment screening. Metabolomic analysis revealed differential metabolites and pathways between groups. Combined analyses indicated that lung inflammation is influenced by genetic, allergenic, and environmental factors disrupting oxidative phosphorylation in lung mitochondria, affecting the TCA cycle. Mitochondrial reactive oxygen species, glutathione S-transferases, arginase 1 and RORC in immune regulation, the Notch pathway, YPEL4 in cell proliferation, and MARCKS in airway mucus secretion play roles in asthma pathogenesis. This study highlights that many cytokines and signaling pathways contribute to asthma. Further studies are needed to elucidate their complex interactions.

Reproductive traits are critical for improving productivity and profitability in the pig industry, and genome-wide association studies (GWASs) are a powerful tool in detecting genetic markers related to target traits. Genome imputation provides an effective approach to obtain a greater number of genetic markers from low-density sequencing data. China’s pig industry recently introduced an imputation panel and is now seeking to determine what types of data are required to meet breeding needs. In this study, we collected and analyzed two pig sequencing datasets, including Yorkshire pig (YY), Landrace pig (LL), and Duroc pig (DD), genotyped by either an SNP chip (n = 816) or genotyping-by-targeted sequencing (n = 314), and applied an imputation strategy before validation in a third dataset (n = 2401). The aim of this study was to identify SNPs associated with reproductive traits and compare imputation results of two different types of data to evaluate whether sample size or marker density more strongly impacts imputation-enabled GWAS performance. Through a GWAS, we identified 73 significant SNPs from imputed Chip data across seven reproductive traits, 94 SNPs from imputed GBTS data across three traits, and 34 SNPs from the combined dataset across seven traits. Seven of these SNPs passed validation and were associated with number born alive, number born healthy, and gestation length. Gestation length (GL) and number born alive (NBA) are the most noteworthy traits. LOXL2 and PTPRD are high-confidence candidate genes affecting GL and NBA, respectively. In addition to LOXL2, STC1, NKX2-6, HMGCLL1, MLIP, TINAG, FAM83B, GFRAL, HCRTR2, ENTPD4, MYH8, IER5L, and U5 are associated with GL. Moreover, in addition to PTPRD, KLHL32, U6, MMS22L, and FHL5 are associated with NBA. The results of this study indicate that sample size is of greater importance than marker density in imputation strategies and provide beneficial insights into genes affecting pigs’ reproductive traits.

Uterine microbiome homeostasis and antioxidant capacity are critical for sow fertility. While high-fiber diets and N-carbamylglutamate (NCG) individually enhance sow fertility, their synergistic effects on the antioxidant status, microbiota, metabolites, and transcriptome remain unclear. Here, sows were assigned to the low-fiber (3.73%) or high-fiber (7.46% crude fiber) group, each without or with 0.05% NCG, throughout the 114-day gestation. Sex hormones and antioxidants in serum were detected. Multi-omics approaches were employed to investigate the impact of a high-fiber diet supplemented with NCG (H + N) on uterine microbiota, metabolites, and gene expression profiles. The study revealed that H + N significantly increased total antioxidant capacity (T-AOC) level in serum. Metagenomic analysis revealed an increased abundance of Clostridium disporicum in the uterine microbiota. Plasma metabolomics identified hydroxylysine as a key metabolite mediating this effect, and this metabolite was positively correlated with elevated abundance of Clostridium disporicum. Subsequent transcriptomic profiling revealed activation of the PI3K-Akt signaling pathway, closely linked to improved T-AOC level. Overall, these findings demonstrated that H + N could modulate the uterine microbiota (specifically Clostridium disporicum), increase hydroxylysine production, and activate the PI3K-Akt signaling pathway. These effects further enhanced hormonal activity and antioxidant capacity, ultimately improving sow reproductive efficiency.