Acute feed intake and acute-phase protein responses following a lipopolysaccharide challenge in pigs from two dam lines.
This study was conducted to evaluate the response of two dam lines of pigs to acute increases of LPS. Acute-phase proteins were also measured to determine their potential use as biological indicators of the immune response. Thirty-six pigs (initial body weight = 21.3 +/- 0.48 kg) were allotted by dam line (Lines 1 and 2) and sex (castrates and gilts) to one of three LPS dose treatments and penned individually. Treatments were a single i.m. injection of 0 (LPS-0), 25 (LPS-25) or 50 microg LPS/kg body weight (BW) (LPS-50). Acute changes in feed intake were related to a pre-injection baseline intake. Feeders were weighed daily to establish baseline feed intake (average daily feed intake -48 to 0 h prior to injection). The acute feed intake response (AFIR) was computed as the average daily feed intake 0-48 h after injection divided by baseline intake. Serum was harvested at time 0 and 48 h after injection. LPS-0 pigs grew faster and consumed more feed than the LPS-25 or LPS-50 pigs (0.79 kg/d versus 0.51 and 0.50 kg/d; 1.15 kg/d versus 0.96 and 0.89 kg/d, respectively; P<0.001). The AFIR of Line 1 castrates and Line 2 gilts was similar for LPS-25 and LPS-50 treatments, while Line 1 gilts and Line 2 castrates had decreased AFIR with increased LPS dose (sex x line x LPS, P<0.05). Three of 18 castrates died but no gilts died following the LPS challenge (P<0.10). Castrates had higher haptoglobin (Hpt) concentrations than gilts on d 0 (18.1 units of absorption/mg of protein versus 13.1 units of absorption/mg of protein; P<0.03). Line 1 pigs had higher C-reactive protein (CRP) concentrations than Line 2 pigs (P<0.05) on d 0. LPS treatment did not change serum concentrations of CRP, Hpt or ceruloplasmin (Cp). However, the change in serum amyloid A (SAA) concentration decreased quadratically (from 0 to 48 h) with increasing LPS dose (P<0.02). This change in SAA was negatively correlated with the AFIR (r= -0.80; P<0.001). In general, castrates appear to be more sensitive to endotoxin challenges than gilts. Serum amyloid A, but not the other acute-phase proteins evaluated, was a good biological indicator of immune system activation following an acute lipopolysaccharide challenge when compared to the acute change in feed intake.
Department of Animal Sciences, University of Missouri, Columbia, MO 65211, USA.
J W
JW
Frank
M A
MA
Mellencamp
J A
JA
Carroll
R D
RD
Boyd
G L
GL
Allee
D000209:Acute-Phase Proteins / Q000378:metabolism*; D000210:Acute-Phase Reaction / Q000097:blood / Q000139:chemically induced / Q000503:physiopathology; D000818:Animals; D002097:C-Reactive Protein / Q000378:metabolism; D002570:Ceruloplasmin / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004435:Eating / Q000187:drug effects*; D005260:Female; D006242:Haptoglobins / Q000378:metabolism; D008070:Lipopolysaccharides / Q000008:administration & dosage / Q000633:toxicity*; D008297:Male; D009919:Orchiectomy; D010052:Ovariectomy; D000685:Serum Amyloid A Protein / Q000378:metabolism; D013045:Species Specificity; D034421:Sus scrofa / Q000097:blood*
D000209:Acute-Phase Proteins; D006242:Haptoglobins; D008070:Lipopolysaccharides; D000685:Serum Amyloid A Protein; D002097:C-Reactive Protein; D002570:Ceruloplasmin