Differentially expressed genes in the caecal and colonic mucosa of Landrace finishing pigs with high and low food conversion ratios

Abstract

The feed conversion ratio (FCR) is an essential economic trait for pig production, and is directly related to feed efficiency. Studies identifying the differential expression of functional genes involved in biological and molecular mechanisms in the intestine in relation to growth performance are rare. In this study, RNA-Seq was used to identify transcriptomes in caecal and colonic mucosal tissues in order to determine the differential expression of genes from two full-sibling pairs and two half-sibling pairs of Landrace finishing pigs with opposing FCR phenotypes. In total, 138 (comparison of high and low FCR in caecal mucosa), 64 (comparison of high and low FCR in colonic mucosa), and 165 (contrast between the caecal and colonic mucosa) differentially expressed genes were identified. Some of these genes were functionally related to energy and lipid metabolism, particularly short chain fatty acids metabolism, as well as gastrointestinal peristalsis and ion transport. Functional annotation were performed to identify differentially expressed genes, such as GUCA2A, GUCA2B, HSP70.2, NOS2, PCK1, SLCs, and CYPs, which may positively influence feed efficiency in Landrace pigs. These differentially expressed genes need to be further tested for candidate genes that are related to feed efficiency.

Differences in gut microbiota composition in finishing Landrace pigs with low and high feed conversion ratios

“…In a study of the same batch of animals (Tan et al 2017a , b ), Firmicutes and Bacteroidetes were the most abundant phyla in cecal and colonic microbiota of pigs in both groups, consistent with other studies (Kim and Isaacson 2015 ; Pedersen et al 2013 ). The dominant genera were Prevotella and Bacteroides .…”

“…The cecum of individuals with high FE contained differentially abundant genes that affect the host energy absorption, mainly through the pyruvate-related metabolism pathway, such as phenylalanine metabolism, synthesis and degradation of ketone bodies, arginine and ornithine metabolism, etc. (Tan et al 2017a , b ). The different metabolic pathways were significantly enriched in the colonic microbiota of the low FE group, partly because of the larger number of genes were more abundant in the low group, and possibly due to incomplete digestion of colonic nutrients, leaving more food residues in the colon that result in greater microbial activity.…”

“…While the colon itself does not perform digestion, microbes in the colon can digest cellulose and synthesize vitamins. The differentially expressed genes of the intestinal mucosa in the cecum and colon between the high and low FCR groups were analyzed, respectively, revealed some candidate genes that might be correlated with the FE, and the subsequent functional verification could be carried out in future (Tan et al 2017a , b ).…”

“…Therefore, the diversity of the gut microbiota is a factor in animal productivity, even under the same rearing conditions. In previous studies, we found that some probiotics, such as Lactobacillus, tend to be enriched in the cecal microbes and colonic microbes that provide high FE, compared to lower FE animals that had a higher proportion of Prevotella (Tan et al 2017a , b ). Functional analysis revealed that differentially expressed genes affect the host’s energy absorption mainly through pyruvate-related metabolism in cecal microbiota.…”

Identification of Important Proteins and Pathways Affecting Feed Efficiency in DLY Pigs by iTRAQ-Based Proteomic Analysis

“…As a complex economic trait, FE is affected by genetics and environmental factors [6]. Low FCR and RFI ratios correspond to high FE [7]. Previous studies have found that low-RFI pigs have more effective and coordinated immune capabilities than high-RFI pigs.…”