Effects of chromium supplementation and lipopolysaccharide injection on physiological responses of weanling pigs

Sixteen specific pathogen free 4-wk-old crossbred weanling pigs were allotted into a 2 x 2 Factorial design to evaluate chromium picolinate (CrPic) on growth and physiological responses. Two factors included (1) no Cr or 400 ppb Cr supplementation from chromium picolinate and (2) lipopolysaccharide (LPS) injection on day 21 (d 21) and 35 (d 35) compared to saline application. Plasma samples and rectal temperature were obtained from all piglets before (h 0) and at 2 h (h 2), 4 h (h 4), 8 h (h 8), and 24 h (h 24) after LPS injection (200 mu g/kg BW, intraperitoneally). The rectal temperature on d 21 was significantly decreased (p<0.05) of about 0.36 degrees C with Cr supplementation before LPS injection. After LPS injection, the daily gain of piglets was decreased during d 35-38. Supplementation of Cr had no effect in general on growth performance particularly after LPS injection. The plasma glucose, triglycerides and urea nitrogen concentrations were changed in different ways after LPS injection. Plasma cortisol level was significantly elevated at h 2 after LPS injection on d 21 and d 35. The supplementation of CI in the diet can delayed plasma cortisol release on d 35. The results suggest thar 400 ppb Cr supplementation from CrPic may modulate the physiological response during immune stress in weanling pigs.