Effects of Intrauterine Growth Retardation on Growth, Meat Quality and Muscle Fiber Composition of Pigs

The aim of this study was to investigate the effects of intrauterine growth retardation (IUGR) on growth, meat quality and muscle fiber composition in pigs. Sixteen piglets with normal birth weight (NBW, body weight (BW) = 1.71 +/- 0.04 kg) and sixteen piglets of low body weight with IUGR (BW = 0.93 +/- 0.03 kg) at birth were procured. Blood samples were collected at 28, 66, and 160 days of age from both groups. Longissimus dorsi muscle samples were collected from four selected pigs at 160 days of age. Body weight, ADG and ADFI were decreased significantly by IUGR from birth to 160 days of age (P<0.05). At 28 and 160 days of age, the serum urea nitrogen levels of the IUGR pigs were significantly higher than the NBW pigs (P<0.05). The serum insulin levels of the IUGR pigs were significantly lower (P<0.05) than the NBW pigs at 28 and 66 days of age. The serum leptin level was significantly higher (P<0.05) in the IUGR pigs at 28 days of age while it decreased significantly (P<0.05) at 160 days of age as compared to the NBW pigs at the same age. Fatty acid composition of the longissimus dorsi muscle was not affected by IUGR (P>0.05). Furthermore, b*, L*, and C* values, pressure loss, and the ratio of MyHC IIb to other isoforms of the longissimus dorsi muscle were increased significantly by IUGR (P<0.05). Our results suggested that IUGR resulted in low postnatal growth rates, increased ratio of MyHC IIb to other isoforms, lower water-holding capacity and meat color of slaughtering pigs.