Location: Genetics and Animal BreedingTitle: Characterization and comparative analysis of transcriptional profiles of porcine colostrum and mature milk at different parities
Submitted to: BMC Genomic Data
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/29/2021
Publication Date: N/A
Interpretive Summary: Piglet growth and survival are critical to the swine industry. Progeny born to primiparous sows (gilts) are born lighter, grow slower, and have higher mortality rates than those born to multiparous sows. It has been hypothesized that differences in lifetime performance between gilt progeny and sow progeny may be due to differences in lactation performance. A limited number of transcriptomic studies related to porcine milk production have been reported. ARS scientists performed RNA-sequencing on porcine colostrum and mature milk samples, from dams in parities one through four, in order to characterize gene expression differences between colostrum and mature milk, as well as differences in gene expression across sow parities. A total of 44,234 transcripts were identified in the samples. These included 41,875 transcripts that have previously been annotated in the swine genome and 2,359 novel transcripts. Fifty genes were determined to be differentially expressed between colostrum and mature milk samples, regardless of parity, and 468 genes were found to be significantly different between colostrum and mature milk across parity. Many of these genes are involved in pathogen recognition and immune response. This is the first study to describe the whole milk transcriptomic profile of porcine colostrum and milk across multiple parities. Findings from the study have produced several highly specialized and functional candidate genes that may contribute to postnatal development and growth of piglets, as well as lactation in the sow.
Technical Abstract: The expression of genes and their regulation during lactation in swine is not well-understood. In order to gain a better understanding of genes and pathways involved in sow lactation, total RNA from colostrum and mature milk samples were sequenced from 65 sows across four parities. A stringent bioinformatic pipeline was used to identify and characterize 44,234 transcripts. The 44,234 identified transcripts included 41,875 previously annotated transcripts and 2,359 novel transcripts. Differential gene expression analysis was conducted using a generalized linear model coupled with the Lancaster method for P-value aggregation across transcripts. In total, 50 differentially expressed genes (DEG) were identified for the milk type main effect, and 468 DEG were identified for the milk type x parity interaction. While no gene ontology (GO) terms or pathways were significant for the milk type main effect, several GO terms related to pathogen recognition and immune response, including response to bacterium, response to lipopolysaccharide, cellular response to lipopolysaccharide, response to molecule of bacterial origin, and lymphocyte activation involved in immune response, were significantly enriched in the DEG set for the milk type x parity interaction. This is the first study to perform global transcriptome analysis from whole milk samples in sows from multiple parities. Our results provide important information and insight into synthesis of milk proteins and innate immunity and potential targets for future improvement of swine lactation.