Net effect of an acute phase response--partial alleviation with probiotic supplementation.

The acute phase response (APR) is characterized by inflammation, fever, and altered organ metabolism resulting in muscle catabolism and anorexia. Lipopolysaccharide (LPS)-induced APR may reflect depressed growth and appetite loss. Therefore, a 1-wk growth experiment was conducted to examine whether dietary supplementation of a multispecies probiotic (PoultryStar) would alleviate growth suppression and anorexia caused by LPS-induced APR. The experiment was designed with 4 treatments (n = 8 cages/treatment; 6 birds/cage) starting at 14 d of age. Before (0 to 14 d of age) and for the experiment (14 to 21 d of age), male broiler chicks were fed diets devoid of probiotic or were supplemented with 1.7 x 10(8) cfu/kg of probiotic. At 14 d of age, birds fed the diet devoid of probiotic were further divided into 3 treatments: an unchallenged positive control, LPS-challenged negative control (LPS-NC), and a treatment that was pair-fed to LPS-NC. The probiotic-fed birds were also then challenged with LPS. The LPS (Escherichia coli 055:B5) was injected intraperitoneally 4 times at 48-h intervals at 1 mg/kg of BW. The LPS challenge dramatically depressed BW gain from 14 to 21 d of age by 22% (P < 0.001). However, 41% of growth depression was attributable to factors other than feed intake reduction when compared with the pair-fed treatment. Probiotic supplementation recovered 17% of depressed growth (vs. LPS-NC; P = 0.068), but this improved growth was not due to improvements in feed intake (P = 0.47). However, recovery of feed intake of the probiotic + LPS birds occurred 48-h earlier than the LPS-NC birds. Growth depression induced by LPS administration resulted in an overall relative feed intake (vs. positive control) of 0.83 and also decreased net energy and protein accretion. Probiotic supplementation did not alleviate the reduction in net energy or protein accretion induced by LPS. In conclusion, APR (induced by LPS administration) diverted a large portion of consumed nutrients from tissue accretion. Probiotic supplementation lessened the anorexic effects of LPS resulting in a trend toward BW gain improvement versus the LPS-NC.