GROWTH-PERFORMANCE AND ENZYME DEVELOPMENT IN WEANLING PIGS INJECTED WITH DEXAMETHASONE

Three experiments were conducted to evaluate the effects of dexamethas one (DEX) on growth performance and on selected digestive enzyme activ ities in weanling pigs. In Exp. 1, 96 pigs (6.7 kg BW and 27 d) were u sed in a 3 x 2 factorial combination of three DEX frequencies (no inje ction; 1 mg DEX/kg BW 3 d before weaning; and 1 mg DEX/kg BW 6 and 3 d before weaning) and two feeding regimens: a simple diet fed throughou t the 28-d trial, or a semicomplex diet fed during the first 14 d post weaning, followed by the simple diet. Growth performance was not affec ted (P > .10) by hormonal treatment. Pigs fed the simple diet had a gr eater ADFI after d 15 postweaning (P < .10) and higher ADG from 15 to 21 d postweaning (P < .01). In Exp. 2, 80 pigs (7.2 kg BW and 26 d) we re assigned 3 d before weaning to four dosages of DEX (0, .33, .66, an d .99 mg/kg BW). Growth performance was similar regardless of DEX dosi ng. In Exp. 3, 24 pigs (6.4 kg BW and 21 d) were injected with DEX (1 mg/kg BW) or saline solution on d 3 before weaning. Four pigs per trea tment were slaughtered at weaning, or on d 3 and d 6 postweaning. Dexa methasone resulted in greater (P < .10) pancreas weight and increased (P < .01) total activity of amylase and sucrase, but lactase was lower ed (P < .10). Dexamethasone injection enhanced digestive enzyme activi ty but failed to improve performance, presumably because of the reduce d feed intake of pigs at weaning.