title: Effects of immune challenge on concentrations of serum insulin-like growth factor-I and growth performance in pigs.
abstract: This study was designed to determine the long-term effects of repeated endotoxin treatment or immunization against human serum albumin on concentrations of serum insulin-like growth factor-I (IGF-I) and other indicators of growth performance in growing pigs. Thirty gilts (38.5 +/- 0.9 kg) were randomly assigned to 5 treatment groups (n = 6 animals/group): 1) lipopolysaccharide injections, 2) lipopolysaccharide pair-fed, 3) human serum albumin immunization, 4) human serum albumin pair-fed, and 5) control. Pigs in the lipopolysaccharide group were treated intramuscularly with lipopolysaccharide on Days 0-3. The pigs in the human serum albumin group were immunized with human serum albumin emulsified in Freund's adjuvant on Day 0 and administered a booster on Day 28. The lipopolysaccharide pair-fed pigs were matched by body weight and pair-wise fed with pigs treated with lipopolysaccharide. Similarly, human serum albumin pair-fed pigs were matched to human serum albumin immunized pigs. Serum IGF-I concentrations did not differ between or within groups. There was no difference in feed disappearance between groups prior to the initiation of treatments. The lipopolysaccharide group had a decrease (P = 0.013) in feed disappearance on Day 0 compared with control and human serum albumin groups. On Day 1, both lipopolysaccharide and human serum albumin groups differed (P < 0.05) from control. Average daily gain and total weight gain did not differ between groups; however, feed efficiency differed (P < 0.05) between lipopolysaccharide and control groups. Long-term effects of repeated endotoxin challenge or immunization on IGF-I concentrations and growth were not evident in the present study. This failure presumably was due to the development of endotoxin tolerance and a relatively innocuous vaccination against human serum albumin.
authors.affiliation: College of Veterinary Medicine, North Carolina State University, Raleigh 27606-1499, USA.
authors.forename: W
authors.initials: W
authors.lastname: Hevener
authors.forename: P A
authors.initials: PA
authors.lastname: Routh
authors.forename: G W
authors.initials: GW
authors.lastname: Almond
mesh_terms: D000818:Animals; D004435:Eating; D005260:Female; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000494:pharmacology; D012709:Serum Albumin / Q000276:immunology; D013552:Swine / Q000254:growth & development* / Q000276:immunology*; D015430:Weight Gain
chemical_list: D008070:Lipopolysaccharides; D012709:Serum Albumin; D007334:Insulin-Like Growth Factor I