|Carroll, Jeffery - Jeff Carroll|
|Matteri, Robert - Bob|
Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: 3/15/2000
Publication Date: N/A
Technical Abstract: Previously we reported that pigs fed SDP have a greater HPA axis response (i.e., higher serum ACTH and cortisol) following an LPS challenge than non-SDP fed pigs. The objective of this study was to evaluate the effect of SDP and an LPS challenge on immune function. Twenty pigs (14 d, 5 kg) were weaned to an isolated environment and allotted to 1 of 4 treatments in na 2x2 factorial arrangement, with two levels of SDP (0 vs 7 percent) and two i.p. injections (LPS vs saline). Diets, formulated to contain equal ME and digestible essential amino acids, were fed for 7 d postweaning. On d 7, i.p. injections of either LPS (150 ug/kg BW) or saline were given, followed by blood sample collection at 15-min intervals for 3 h. After 3 h, pigs were sacrificed and tissue was collected for mRNA analysis of IL-1beta and IL-6. The serum TNF-alpha response to the LPS challenge was greater for pigs fed the SDP diet (peak was 15.7 ng/ml at 1.25 h post-challenge) compared to pigs fed the non-SDP diet (peak was 6.3 ng/ml at 1.5 h post-challenge) The serum IFN-gamma response 3 h post-LPS was greater in pigs fed the SDP diet (1.75 ng/ml) than pigs fed the non-SDP diet (.24 ng/ml). There were diet by LPS interactions for IL-1beta in the adrenal (P<.06, spleen (P<.002) and thymus (P<.023) such that LPS decreased IL-1beta expression only in pigs fed the non-SDP diet. SDP fed pigs had lower levels of IL-6 mRNA in the adrenal gland, spleen, and the pituitary (p<.05), but not the hypothalamus or thymus gland. These results are consistent with studies that demonstrate that immunologically naive mice respond much greater to an LPS challenge than immunologically primed mice. This suggests that feeding SDP may provide immunological protection for weaned pigs under typical production conditions.