The effect of dietary protein on performance and immune response in weanling pigs subjected to an inflammatory challenge

A total of 96, 21-d-old, crossbred weanling pigs (average initial weight was 6.0 kg) were assigned to one of six treatments to investigate the effect of dietary protein on performance and immune function of Escherichia coli lipopolysaccharide (LPS)-challenged and unchallenged pigs. A control diet was formulated to contain 14.7 MJ of DE/kg, 14 g of CP/MJ of DE, and 7 g of lysine/100 g of CP. Diets low and high in protein were formulated by changing protein levels to 60 or 120% of the control diet. On d 7 and 21, pigs were challenged with either a LPS solution or a saline solution. Lymphocyte blastogenesis was measured 2 d after LPS challenges and antibody response to sheep red blood cells (SRBC) or ovalbumin was measured 3 d after the challenges. Gain and feed consumption were determined 3 d after each LPS injection and at weekly intervals for a total period of 5 wk. Injection of LPS decreased daily gain, feed intake, feed efficiency, and efficiency of protein utilization (P < .05). No interactive effects between LPS challenge and dietary protein were observed for pig performance (P > .10). Daily gain and feed efficiency were improved when protein level was increased from 60 to 100% of the control diet (P < .01). Efficiency of protein utilization for weight gain was lower when the 120% protein diet was fed (P < .01). Antibody response to SRBC or ovalbumin was not affected by treatments.(ABSTRACT TRUNCATED AT 250 WORDS)