Transcriptome analysis of the diurnal gene expression in the intestines of Pelteobagrus vachellii

Abstract: In aquaculture, it is necessary to determine of the diurnal biological variations in the intestines to determine an appropriate feeding schedule. The present study aimed to examine the transcriptomes of the Pelteobagrus vachellii intestines at four time points (0h, 6h, 12h, and 18h) within a light/dark cycle. In comparison with the zeitgeber time 0 (ZT0) transcriptomes, we identified 37,842 unigenes with significant differential expression, including 6,638; 9,626; and 7,938 that genes upregulated, and 3,507; 4,703; and 5,412 genes that were down regulated at 4, 12, and 24 h respectively. The differentially expressed unigenes were subjected to enrichment analysis, which indicated the involvement of the major digestive pathways, including digestion of protein, lipid and carbohydrate, catabolic process (protein, carbohydrate and lipid), and circadian rhythm. We selected 73 key differentially expressed genes (DEGs) from among these pathways and identified DEGs that showed increased expression at night, including those encoding trypsin-3, chymotrypsinogen 2, amino acid transporter, maltase-glucoamylase, facilitated glucose transporter, lipase, phospholipase, fatty acid-binding protein, fatty acid synthase, long