The Molecular Mechanism Of Ammonia On Growth And Development Of Breast Muscle In Broilers Based On RNA-Seq

Ammonia as a major aerial pollutant of poultry buildings is causing increasing problems with broiler health and production in poultry industry.Previous reports demonstrate that high levels of ammonia(75 ppm)alter body fat distribution and meat quality of broilers.However,the molecular mechanisms and metabolic pathways in breast muscle altered by ambient ammonia exposure on broilers are still unknown.At the same time,for the consideration of human health,the limit exposure concentration of ammonia in houses is set at 25 ppm.Previous reports have shown that 25 ppm is still detrimental to livestock,especially the respiratory tract,but the negative relationship between ammonia exposure and the tissue of breast muscle of broilers is still unknown.This study utilized RNA-Seq to compare the transcriptomes of breast muscles to identify differentially expressed genes in broilers exposed to high and low concentrations of atmospheric ammonia.This study provides new information that could be used for genetic breeding and nutritional intervention in production practice of broilers industry in the future.In the present study,A total of 267 promising candidate genes(fold change ? 2 or? 0.5;P<0.05)were identified between Ammonia75 and Ammonia25 groups,among which 67 genes were up-regulated and 189 genes were down-regulated.Bioinformatics analysis suggested that the up and down-regulation of these genes were involved in the following two categories of cellular pathways and metabolisms:Steroid biosynthesis and peroxisome proliferator-activated receptor(PPAR)signaling pathway,which both participated in the lipid metabolism processes.25 ppm ammonia in poultry houses was found to lower slaughter performance and breast yield.The transcriptome analysis showed that 163 genes(fold change ? 2 or? 0.5;P<0.05)were differentially expressed between Ammonia25(treatment group)and Ammonia3(control group),including 96 down-regulated and 67 up-regulated genes.Gene Ontology functional annotation analysis revealed potential genes,processes and pathways with putative involvement in growth and development inhibition of breast muscle in broilers caused by aerial ammonia exposure.These findings provide novel insights into our understanding of molecular mechanisms of breast muscles exposed to ammonia in broilers.This study facilitates understanding of the genetic architecture of the chicken breast muscle transcriptome,and has identified candidate genes for breast muscle response to atmospheric ammonia exposure.