1184
High energy diet enhances intramuscular adipogenesis in Hanwoo steers distributed to breeding value for meat quality
High energy diet has been used for enhancing intramuscular adipose tissue in high quality beef cattle. Estimated breeding value (EBV) was used as a selection method to determine high quality beef group. The aim of this experiment was to determine the effect of high energy diet on the high and low beef group distributed by EBV for carcass quality grade. We hypothesized that adipogenic gene expressions and adipose carcass traits are increased in high EBV groups when fed a high energy diet. A 2 x 2 factorial arrangement (High EBV, Low EBV, and High energy diet, control diet) in a completely random design was used to feed 26 Hanwoo steers. Two steers were fed in same pen and 13 pens were used for treatment. Blood sample was drawn once a month at the beginning from 11 to 28 month. Longissimus Dorsi (LD) muscle was collected within 10 min of harvest for analysis of mRNA SCD, PPARγ, GLUT4, MHC1, MHC2X abundance. Overall ADG and DMI were not different between high energy diet and control diet (P >0.05). Serum glucose and triglyceride concentrations were increased (P <0.05) by high EBV group from 22 to 28 month old. Serum NEFA levels were greater (P <0.05) in 24 month old at high EBV group and steady decreased at 28 months old. Marbling score and yield grade were not affected by high energy diet and EBV (P >0.05). Real-time quantitative PCR revealed that the mRNA content of PPARγ and SCD of high EBV group increased (P < 0.05) as compared to low EBV group. The mRNA level of GLUT4 and MHC1 tend to increase (P = 0.08, 0.09) when control diet fed at high EBV group. These data indicate that high energy diets increased serum glucose and triglyceride concentrations of high EBV-steers at final fattening period. Although there are no interaction between diet and EBV levels, adipogenic gene expressions in high EBV-steers were greater than those in low EBV-steers. The selection of EBV for meat quality affected serum glucose level and adipogenic gene expression of feedlot Hanwoo steers.
Keywords:
Hanwoo, EBV, adipogenesis.