The Effect of Vitamin A Restriction on Marbling and Adipogenic Gene Expression in Commercial Angus and Simmental Steers

Vitamin A (Vit-A) restriction has been shown to increase marbling in cattle. Our hypothesis for this study was that a low Vit-A diet would increase marbling and improve meat quality characteristics while having no effect on production characteristics of Angus cross and Simmental steers. We also hypothesize that expression of proadipogenic factors such as PPAR?, C/EBP?, and FABP4 will be upregulated, and anti-adipogenic factors such as PREF-1 down regulated in cattle with high marbling scores. Treatments consisted of an unsupplemented VA basal diet and a VA supplemented diet at 2200IU/kg DM, arranged in a 2x2-treatment arrangement with breed. There was a significant interaction between breed and treatment on marbling score (P = 0.008), Angus cross steers on the low Vit-A treatment had the greatest marbling and resultantly the greatest quality grades (P = 0.02)