Intrauterine growth-restricted piglets have similar gastric emptying rates but lower rectal temperatures and altered blood values when compared with normal-weight piglets at birth

Intrauterine growth-restricted (IUGR) piglets have lower survival rates and are more likely to have empty stomachs 24 h after birth than normal piglets. Although hypoglycemia may result from low colostrum intake per se, it is not known if slow gastric emptying may be an additional risk factor for poor immunization and glucose absorption in IUGR piglets. It is estimated that IUGR piglets consume less colostrum per kilogram BW than normal-weight piglets within the first 24 h, which could be due to a slower gastric emptying rate and a compromised energy metabolism. Therefore, we hypothesized that the gastric emptying rate and blood glucose would be lower in IUGR piglets. We investigated gastric emptying rates in normal and IUGR piglets and blood glucose and rectal temperatures at birth and after 15, 30, 60, and 120 min. In addition, blood parameters relevant for metabolism were studied. Forty-eight piglets (24 normal and 24 IUGR) were classified at birth as either normal or IUGR on the basis of head morphology. Piglets were removed from the sow at birth before suckling, and birth weight was recorded. Pooled porcine colostrum was tube-fed to all piglets at 12 mL/kg BW as soon as possible after birth (t = 0 min). The piglets were randomly allocated to be euthanized at 15, 30, 60, and 120 min (all groups, n = 6) after bolus feeding, and the weights of the stomach and its residuals were recorded. There was no difference in gastric emptying rates between normal and IUGR piglets (P = 0.129); however, gastric DM residuals tended to by greater in IUGR piglets than normal piglets (P = 0.085). Overall, IUGR piglets had lower rectal temperatures (36.2 degrees C +/- 0.2 degrees C vs. 37.5 degrees C +/- 0.2 degrees C; P < 0.001) and plasma glucose levels (2.8 +/- 0.2 vs. 4.1 +/- 0.2 mmol; P < 0.001) than normal piglets. Interactions between piglet classification and time were observed in plasma values for NEFA, d-3-hydroxybutyrate, albumin, aspartate, and alanine amino transferase, with greater levels in normal piglets at 15 min (P < 0.05) and 30 min for bile acid (P < 0.05) compared to IUGR piglets. In conclusion, the gastric emptying rates between normal and IUGR piglets were similar, but gastric DM residuals tended to be greater in IUGR piglets. Differences were observed in blood values and rectal temperatures, with lower values in IUGR piglets. Therefore, it is likely that factors like hypothermia and possibly reduced metabolic function are more important during the first hours after birth than gastric retention per se.