PSVI-23 - Depot- specific Patterns of mRNA and miRNA Gene Expression in Adipose Tissue from Texel-Cross and Suffolk Lambs

Excess fat deposition is costly to the producer in terms of input and final product; it also usually does not occur equally across all adipose depots. Further examination is necessary to determine a correlation between varying gene expression and fatty acid composition in different tissue depots, and further, across different breeds. Texel-Suffolk (n = 5) and Suffolk-Suffolk (n = 4) lambs were finished to 203 d of age and used to compare both mRNA and microRNA (miR) gene expression changes between breed and among tissue depots. Seven different depots were harvested and snap-frozen from all nine lambs. The liver, longissimus muscle of the rib, kidney fat, mesenteric fat, omental fat, subcutaneous fat, and intermuscular fat were all harvested. Texel-sired lambs had greater (P < 0.05) flank streaking, quality grade, and weight of fat depots compared to Suffolk. Texel-cross lambs had higher (P < 0.05) oleic-to-stearic fatty acid ratio than Suffolk lambs in this study, displaying a breed difference concerning this desaturation ratio. Tissue and breed interactions were observed for oleic-to-stearic and palmitoleic-to-palmitic ratio differences (P < 0.05) depending on tissue type. Tissue and breed interactions were trending in various tissues concerning the expression of the gene, stearoyl-CoA desaturase-1(SCD-1). SCD-1 seemed to be upregulated (P < 0.10) in a multitude of tissues while others do not appear to be differentially expressed, dependent upon breed. Data showed an association between SCD-1 and mi-199a-3p among different tissue variations. This may suggest that adipose tissue is more complex than what is currently known. Lipogenic gene expression differed between tissue and adipose depots, and could potentially broaden targets that could aid in maximizing animal efficiency.