Analysis of the basal colonic innate immune response of pigs divergent in feed efficiency and following an ex vivo lipopolysaccharide challenge

Abstract

While feed efficiency is influenced by multiple physiological processes, it is not known how efficient and inefficient pigs differ in relation to their basal immune response, and particularly their innate immune response to a microbial challenge. Hence, the objective was to examine the expression of genes encoding innate immune response markers in basal colonic tissue and colonic tissue following an ex vivo lipopolysaccharide (LPS) challenge from pigs divergent in residual feed intake (RFI). Pigs that differed in RFI were selected from two different farms of origin. Colonic tissue was harvested from high RFI (HRFI) and low (LRFI) pigs, and two experimental conditions were explored: the first was basal unchallenged tissue and the second was colonic tissue following an ex vivo LPS challenge. RNA was extracted and tested on a Nanostring panel of 72 genes coding for barrier defense proteins, transmembrane receptors, kinases, transcription regulators, cytokines, and cytokine regulators. In the basal unchallenged tissue, the LRFI pigs had increased expression of AOAH, AP1, and TRAM and the cytokines TNF, IL10, and CXCL8, compared with the HRFI pigs ( P < 0.05), with a significant effect of farm of origin on 31 genes ( P < 0.05). In the LPS-challenged tissues, the LRFI group had higher expression of TLR1, TLR7, TLR8, GPR43/FFAR2, JAK2, and NFAM1 compared with the HRFI group ( P < 0.05). In conclusion, these data suggest that LRFI pigs have an upregulated basal colonic inflammatory state and a heightened response to an LPS challenge compared with the inefficient HRFI pigs. This immune profile potentially enhances their capacity to respond to an infectious challenge.

Identification of key genes and pathways associated with feed efficiency of native chickens based on transcriptome data via bioinformatics analysis

“…In this study, the four hub genes up-regulated in HRFI chickens, which indicated the HRFI chickens increased ROS production and inflammatory response. In agreement, a number of studies have suggested that low feed efficiency pigs showed higher inflammatory responses, growth impairment, and ROS production [26,29]. Similarly, in the above DEGs enrichment analysis, our results indicated that the birds in the HRFI group up-regulated inflammation-related pathways, such as 'phagosome', 'cell adhesion molecules (CAMs)', and 'cytokine-cytokine receptor interaction', and down-regulated genes related to mitochondrial function.…”

“…These results indicated that pathways related to immune response and inflammatory response are associated with feed efficiency. Consistent with previous studies, it is well established that LRFI pigs have an up regulated basal colonic inflammatory state and a heightened response to a lipopolysaccharide (LPS) challenge compared with the HRFI pigs [29]. A similar finding suggested that compared with low feed efficiency pigs, the high feed efficiency pigs could induce a quicker and more effective hepatic response to inflammatory stimuli [24].…”

Analysis of Merged Whole Blood Transcriptomic Datasets to Identify Circulating Molecular Biomarkers of Feed Efficiency in Growing Pigs

“…In the current study, the subsets of genes combined in the predictive models for FE were involved in numerous functional pathways that might be thus at an equivalent importance in the de nition of RFI and FCR. Finding genes of the immune/in ammatory system (including JPH4 and PAG1 genes) as top predictors con rms that low RFI pigs had speci cities in their immune tissue pro le and response capacity to infectious or in ammatory challenges as compared to high RFI pigs [29,30]. The importance of the ubiquitin-regulated protein catabolism (with IRF2BP2 as top VIP) in FE may be overestimated because the current study considered the whole blood where this process is speci cally enriched [31].…”

Laminarin-rich extract improves growth performance, small intestinal morphology, gene expression of nutrient transporters and the large intestinal microbial composition of piglets during the critical post-weaning period

“…Background was corrected for using background thresholding in which a threshold value is set and all counts which fall below that value are adjusted to match it. The background threshold value was estimated using the average count of the negative control probes in every reaction plus 2 standard deviations (18) . Target genes with raw counts below the threshold in more than two thirds of samples were excluded from the analysis.…”