Dexamethasone treatment at birth enhances neonatal growth in swine

The objective of the present study was to determine if dexamethasone (Dex; a potent synthetic glucocorticoid) treatment at birth would alter postnatal growth in neonatal pigs. Forty crossbred pigs were injected i.m. with eith er sterile saline (Cont; n = 10 males and 10 females) or Dex (1 mg/kg; n = 10 males and 10 females) within 1 hr of birth. All pigs remained with their respective dams until 18 d of age. Body weights were recorded weekly and o n d 18. On d 17, all pigs were nonsurgically fitted with an indwelling jugu lar catheter and placed back with the sows. On d 18, all pigs were placed i n individual pens for serial blood collection. Birth weights (1.53 +/- .04 kg) did not differ between birth treatments or sex classes (P > 0.70 and 0. 89, respectively). A time by treatment effect was detected (P < 0.007) for body weight such that those pigs which received Dex at birth had the greate st body weights during the 18-d period. Average daily gain was increased (P < 0.017) by 12.2% in those pigs which received Dex at birth (.286 +/- .007 ) as compared to the Cont pigs (.255 +/- .01 kg/d). Serum concentration of IGF-I was influenced by both treatment (P < 0.0001) and sex class (P < 0.01 3). In the male pigs, Dex increased (P = 0.0041) serum concentration of IGF -1 by 47% as compared to Cont male pigs, whereas in the females, Dex increa sed (P < 0.011) serum concentration of IGF-1 by 34% as compared to Cont fem ale pigs. Dex treatment reduced (P < 0.002) serum IGF-2 by 12.8%. Serum con centration of IGFBP-3 was influenced by both birth treatment (P < 0.007) an d sex class (P < 0.002) such that Dex treatment increased serum IGFBP-3, an d higher concentrations of IGFBP-3 were observed in boars as compared to gi lts. These data suggest that the early neonatal period may be an opportune time to alter physiological factors which influence growth in swine. (C) 20 01 Elsevier Science Inc. All rights reserved.