Transcriptome profile analysis identifies candidate genes of feed utilization in Dorper and Small Tail Han crossbred sheep

High feed utilization efficiency can reduce agricultural costs and pollution. However, the feed conversion ratio (FCR) of local sheep breeds is low in China, so improving FCR of sheep is an important economic and environmental issue. However, the molecular mechanism affecting feed utilization remains unclear. In this study, transcriptome sequencing was used to compare the differences between small intestinal tissues from sheep with high and low feed conversion. The results identified 145 differentially expressed genes (DEGs) between the high and low FCR groups, of which 80 were upregulated and 65 were downregulated. Gene Ontology annotation (GO) and KEGG pathway analysis showed that DEGs were mainly enriched in metabolic processes and lipid metabolism pathways. Glucagon-like peptide 2 receptor (GLP2R) showed a significant negative correlation with feed intake (FI), whereas Lysophosphatidate acyltransferase (AGPAT1) was positively correlated with FCR. Adiponectin receptor2 (ADIPOR2) was negatively correlated with FCR. They may be considered as candidate genes that play a crucial role in feed utilization. Our data provided many valuable candidate genes that will help to study the molecular mechanisms of feed utilization in sheep.