Global gene expression analyses of channel catfish after being fed diets with inclusion of frass from black soldier fly larvae

Frass is the by-product of the larval meal industry and includes larval waste, exoskeleton sheds, and residual feed ingredients. Experimental frass was derived from the larvae of black solder flies (Hermetia illucens) fed distillers dried grains. A 10-week study was conducted to evaluate the effect of dietary levels of frass on the global gene expression of channel catfish, Ictalurus punctatus. Three diets containing 0, 50, and 300 g frass per kg diet were fed to channel catfish (5.24 ± 0.04 g) in quadruplicate aquaria to apparent satiation twice daily. Intestine (n=12 in pools of 3) and liver (n=12 in pools of 3) tissues were taken from fish at the end of the trial and processed for high-throughput Illumina RNA sequencing (RNAseq). Pairwise comparisons identified both up- and down-regulated genes in frass diets compared to no frass controls. Overall design: Comparative gene expression profiling analysis of RNA-seq data from channel catfish pooled liver and spleen tissues after being fed three different diets over a ten week period. Treatments include control diet (no frass inclusion) and two test diets with either 50mg frass inclusion (low frass) or 300mg frass inclusion (high frass). Tissues were pooled from three individuals; four pools were used for library creation and RNA-seq and treated as biological replicates.