Expression of Antisense Long Noncoding RNAs as Potential Regulators in Rainbow Trout with Different Tolerance to Plant-Based Diets.

Reformulation of aquafeeds in salmonid diets to include more plant proteins is critical for sustainable aquaculture. However, increasing plant proteins can lead to stunted growth and enteritis. Toward an understanding of the regulatory mechanisms behind plant protein utilization, directional RNA sequencing of liver tissues from a rainbow trout strain selected for growth on an all plant-protein diet and a control strain, both fed a plant diet for 12 weeks, were utilized to construct long noncoding RNAs. Antisense long noncoding RNAs were selected for differential expression and functional analyses since they have been shown to have regulatory actions within a genome. A total of 142 unique antisense long noncoding RNAs were differentially expressed between strains, 60 of which could be mapped to a gene. Genes underlying these noncoding RNAs are indicated in lipid metabolism and immunity. Six noncoding transcripts were also found to overlap with differentially expressed protein-coding genes, all of which were co-expressed. Associating variation in regulatory elements between rainbow trout strains with differing tolerance to plant-protein diets will assist in future studies toward increased gains throughout carnivorous aquaculture.