Comparative analysis of the liver transcriptome of Pelteobagrus vachellii with an alternative feeding time.

Pelteobagrus vachellii, an important freshwater fish in China, shows predominantly nocturnal behavior. To better understand the growth and molecular mechanisms underlying altered feeding times in this species, we studied the growth and liver transcriptome of P. vachellii with shifted feeding times. In this study, a 9-week growth trial was conducted on male P. vachellii (mean weight±S.E.=1.05±0.36g) with commercial feed. Two triplicate groups of fish were fed either at 0800 (day group, control) or at 2000 (night group) with the same amount of feed. After nine weeks, a significant increase in growth was observed in the night group, demonstrated by the specific growth rate (SGR). Using high-throughput RNA-seq, 70,793,844 and 67,930,610 paired-end clean reads were obtained from six cDNA libraries of P. vachellii liver, and 60,069 unigenes were assembled. Gene expression comparison revealed that 122 genes were significantly up-regulated and 59 genes were significantly down-regulated in the night group. Gene pathway and GO enrichment analyses revealed metabolic responses of genes and gene networks related to protein, lipid and carbohydrate metabolism and rhythms. This study indicates that an alternative feeding time can improve growth and create metabolic alterations in the liver of P. vachellii.