Effects of Dietary Multi-Nutritional Targeted Supplementation According to Different Growth Stages on Performance and Carcass Characteristics of Hanwoo Steers (Report‪)‬

INTRODUCTION Unlike Western society, Korean and Japanese consumers prefer well-marbled and lightly-colored beef. In Korea, Hanwoo steers have been fattened until almost 30 months of age to improve meat quality with high marbling. Hanwoo steers dramatically increase their marbling fat in muscle between 12 and 27 months of age (Lee et al., 2007). Marbling plays a particularly important role in determining the juiciness and tenderness of beef, and is one of the main factors used to determine beef quality grade in Korea (Lee, 2004). However, the color of the beef tends to become darker as the animals become older, although high-marbled beef is produced from animals fed for more than 2.5 years (Zembayashi et al., 1999). Meat purchasing decisions are influenced by color more than any other quality factor because consumers use discoloration as an indicator of freshness and wholesomeness (Mancini and Hunt, 2005). Meat color in beef is related to age. This is because the content of myoglobin in meat steadily increases until 24 months of age, and pigment content increases from birth to 16 months of age (Boccard et al., 1979). In the beef industry, various plant materials containing phenolic compounds have been demonstrated to be effective antioxidants in meat color. Over past years, many experimental feeding trials have focused on vitamin E (a-tocopherol) supplementation of diets of meat-producing animals as a means of enhancing the oxidative stability of post-slaughter meat (Faustman et al., 1989; O'Grady et al., 2006). In addition, Zembayashi et al. (1999) found that the addition of wheat bran or green tea (catechins) to the diet decreased color saturation because these supplements were responsible for low muscle iron concentrations. Oh et al. (2008) also reported that iron and metmyoglobin content of the longissimus dorsi and hemoglobin content of blood were lower in Hanwoo steers fed wheat bran and catechins compared with steers fed a basal diet.