Effect of rumen-protected fat and/or vitamin C supplementation on growth performance, carcass characteristics and meat composition in Hanwoo steers during late fattening period

High-energy diets to steers during the late fattening period, the consumption of large amounts of an energy-rich diet is liable to cause metabolic problems such as ruminal dysfunction and impaired liver-related immune function in beef cattle, as well as an increase in inedible fat. In ruminants, supplementation of rumen-protected fat is an effective approach for increasing energy density and enhancing productivity. In addition, Vitamin C, which is a strong antioxidant, is known to improve meat color by inhibiting phospholipid oxidation and reactive oxygen formation, and has also been found to improve marbling score and meat quality by enhancing adipocyte differentiation. However, studies on Hanwoo steers following the supplementation of rumen protected fat and vitamin C are insufficient. Thus, this study was conducted to investigate the effect of rumen-protected fat and/or vitamin C supplementation on growth performance, carcass characteristics, and meat composition in Hanwoo steers during late period. Twenty-eight Hanwoo steers (initial body weight 723.0 +/- 59.2 kg, approximately 27 months of age) were allotted to 4 treatments as follow: CON = basal diet, T1 = basal diet + rumen-protected fat (RPF) at the level of 0.1% of diet, T2 = basal diet + rumen-protected vitamin C (RPVC) at the level of 0.1% of diet, T3 = basal diet + RPF + RPVC. Final weight, average daily gain and dry matter intake were higher in T1 than in CON (p < 0.05). Plasma metabolites were similar among the treatments. Carcass weight and rib eye area was higher in all treatment group than in CON (p < 0.05). However, there was no effect according to the treatment on the chemical and fatty acid composition of longissimus muscle. The present results suggest that rumen-protected fat and/or vitamin C supplementation has positive effects on concentrate feed intake. In particular, rumen-protected fat was founded to be effective in increasing in dry matter intake, average daily gain, carcass weight and rib eye area of Hanwoo steers. However, there was no complementary effect of rumen-protected fat and vitamin C supplementation.