Seasonal and sex-dependent gene expression in emu ( Dromaius novaehollandiae) fat tissues

Emu ( Dromaius novaehollandiae ) farming has been gaining wide interest for fat production. Oil rendered from this large flightless bird’s fat is valued for its anti-inflammatory and antioxidant properties for uses in therapeutics and cosmetics. We analyzed the seasonal and sex-dependent differentially expressed (DE) genes involved in fat metabolism in emus. Samples were taken from back and abdominal fat tissues of a single set of four male and four female emus in April, June, and November for RNA-sequencing. We found 100 DE genes (47 seasonally in males; 34 seasonally in females; 19 between sexes). Seasonally DE genes with significant difference between the sexes in gene ontology terms suggested integrin beta chain-2 ( ITGB2 ) influences fat changes, in concordance with earlier studies. Six seasonally DE genes functioned in more than two enriched pathways (two female: angiopoietin-like 4 ( ANGPTL4 ) and lipoprotein lipase ( LPL ); four male: lumican ( LUM ), osteoglycin ( OGN ), aldolase B ( ALDOB ), and solute carrier family 37 member 2 ( SLC37A2 )). Two sexually DE genes, follicle stimulating hormone receptor ( FSHR ) and perilipin 2 ( PLIN2 ), had functional investigations supporting their influence on fat gain and loss. The results suggested these nine genes influence fat metabolism and deposition in emus.