Transcriptome responses to dietary aflatoxin B1 exposure in domestic turkey

Dietary exposure to aflatoxin B1 (AFB1) can have severe negative impacts on poultry health and production. Domestic turkeys (Meleagris gallopavo) are especially sensitive to AFB1-induced hepatotoxicity and immunosuppression. In the turkey liver, AFB1 is efficiently activated by cytochrome P450 enzymes (P450s), but cannot be detoxified by alpha-class glutathione-S-transferase enzymes (GSTAs). The overall goals of our study were use RNA-sequencing (RNA-seq) to determine the impacts of AFB1 on the transcriptome in the turkey liver and spleen and evaluate the potential of a Lactobacillus-based probiotic (PB) to reduce aflatoxicity. Male Nicholas turkey poults were randomly divided into 4 treatment groups (CNTL, AFB, PB and PBAFB) and exposed to PB and/or AFB1 according to the protocols described in Monson et al., 2014. Tissue samples were collected for RNA extraction from 3 birds in each treatment upon completion of the challenge trial. Liver RNA samples were pooled by treatment before library construction (n=4 libraries), while spleen samples were run multiplexed as individual libraries (n=12 libraries). Libraries were sequenced on the Illumina GAII and the resulting single-end reads were de novo assembled into predicted transcripts for each tissue. BLAST annotation, differentially expression and functional analysis were used to determine the impacts of AFB1 and PB on expression in the liver and spleen. Candidate genes identified in these transcriptome analyses provide a resource for future research on AFB1 and efforts to increase the resistance of domestic turkeys.