Effect of dietary energy source and immunological challenge on growth performance and immunological variables in growing pigs

Forty-eight growing pigs (23 kg BW) were assigned to four treatments (n = 12) arranged as a 2 X 2 factorial. Dietary energy source (conventional [CON] vs high-oil corn [HOC]), with or without an immunological challenge (IC) regimen constituted main effects. The IC regimen consisted of injection of endotoxin (E. coli lipopolysaccharide [LPS]) and vaccination for porcine respiratory and reproductive syndrome (PRRS). Growth performance data were collected over a 5-wk period and are presented as prechallenge (d 1 to 14; d 1 was the 1st d of the study), challenge (d 15 to 21), and postchallenge (d 22 to 36) periods, and overall. Overall, the pigs fed HOC consumed less feed (P < 0.11) and gained more efficiently (P < 0.03). During the immunological challenge period, ADG was depressed 21% and feed intake 15% (P