Abstract
Feed efficiency is an economically crucial trait for cultured animals, however, progress has been scarcely made in the genetic analyses of feed conversion efficiency (FCE) in fish because of the difficulties in measurement of trait phenotypes. In the present investigation, we present the first application of RNA sequencing (RNA-Seq) combined with differentially expressed genes (DEGs) analysis for identification of functional determinants related to FCE at the gene level in an aquaculture fish, crucian carp (Carassius auratus). Brain tissues of six crucian carp with extreme FCE performances were subjected to transcriptome analysis. A total of 544,612 unigenes with a mean size of 644.38 bp were obtained from Low- and High-FCE groups, and 246 DEGs that may be involved in FCE traits were identified in these two groups. qPCR confirmed that genes previously identified as up- or down-regulated by RNA-Seq were effectively up- or down-regulated under the studied conditions. Thirteen key genes, whose functions are associated with metabolism (Dgkk, Mgst3 and Guk1b), signal transduction (Vdnccsa1b, Tgfα, Nr4a1 and Tacr2) and growth (Endog, Crebrtc2, Myh7, Myh1, Myh14 and Igfbp7) were identified according to GO (Gene Ontology) and KEGG (Kyoto Encyclopedia of Genes and Genomes) annotations. Our novel findings provide useful pathway information and candidate genes for future studies of genetic mechanisms underlying FCE in crucian carp.
Highlights
Aquaculture products are among the most important sources of nutrition for people around the world [1]
Eight quantitative trait loci (QTL) associated with feed conversion efficiency (FCE), an assessment criterion for feed efficiency, were mapped to four linkage groups, explaining 15.2–20.9% of the phenotypic variations, and seven candidate genes related to FCE and its relevant traits involved in several biological processes were identified in crucian carp in a previous study [34]
Our results would provide useful information for a physiological basis to develop improved feed formulas and/or feeding conversions. These novel findings would be useful for such future studies as association analysis and functional verification between candidate genes and FCE traits, thereafter providing proper markers for marker-assisted selection for potential improvement of feed efficiency in crucian carp
Summary
Aquaculture products are among the most important sources of nutrition for people around the world [1]. Since feed cost comprises about 65–75% of the total production cost in most aquaculture species [7], the increasing production demand with huge input cost kept up pressures on us to investigate how to improve feed efficiency. In this sense, breeding fish with high feed efficiency would mean big savings and enhance the profitability of producers. Those identified candidate genes pertain to numerous biological processes [10,16], suggesting that biological strategies involving feed efficiency are diverse
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
