Abstract
This experiment was conducted to determine the effect of energy and protein restriction during nursing period (from 3 to 28 days of age) on intramuscular fat (IMF) accumulation in finishing pigs. Female piglets (n=8) were divided into two groups on two days of age. During nursing period, one group was fed milk substitute to meet nutrient requirements of nursing pigs (Control), and the other was given feed amounting to half of the energy and protein of the Control pigs (Low). Vitamins and minerals were adequate in the feed of both the groups. After the nursing period, all pigs were fed similarly up to the body weight of 115 kg and then slaughtered. Feed intake of the Low group was not different to that of the Control group during growing-finishing period. The body weight gains of the Low group were half that of the Control group during nursing period, but after that the body weight gains of the two groups were the same. The area of muscle fiber and muscle weights in the Low group were lower than those of the Control (P<0.05). The IMF contents and type I collagen contents of muscle in the Low group were higher than those of the Control group at the body weight of 115 kg (P<0.05). In conclusion, the Low group has decreased muscle development and increased collagen content caused by muscle fiber degeneration. Therefore, it was suggested that the restriction of energy and protein during the nursing period resulted in an increase of fat accumulation in the muscle.
