The effect of rumen-protected rice bran oil (RP-RO) supplementation on performance and fatty acid content of crossbred Wagyu beef steers was determined. Twelve crossbred Wagyu beef steers, that averaged 509±3.2 kg live weight and 28 months old, were stratified by their live weight into 3 groups. All steers were fed 7.5 kg/d of 14% crude protein concentrate with ad libitum rice straw and had free access to clean water. The treatments were: 1) control concentrate; 2) supplemented with 100 g/d of RP-RO (100 RP-RO); and 3) supplemented with 200 g/d of RP-RO (200 RP-RO). This present study demonstrated that supplementation of RP-RO did not influence dry matter and crude protein intakes, live weight changes, carcass and muscle characteristics, and sensory or physical properties. RP-RO increased C18:1n-9 and beef marbling scores. Based on the results from the present study, it can be recommended that the addition of 200 g/d RP-RO can increase C18:1n-9 and the beef marbling score.
