LPS induction of innate immune responses to broiler chickens and turkey poults consuming diets naturally contaminated with graded concentrations of deoxynivalenol

Liting Xu, Purdue University

Abstract

Lipopolysaccharide (LPS), a membrane glycolipid of Gram-negative bacteria, leads to an acute inflammatory response, as well as significant physiological changes resulting in cachexia. Two experiments were conducted to determine the impacts of graded concentrations of deoxynivalenol (DON) on performance, intestinal morphology and innate immune response in broiler chickens and turkey poults unchallenged or challenged with LPS. Body weight (BW) gains were cubically or quadratically affect by graded concentrations of dietary DON up to 18 or 10 mg/kg diet in broilers and turkeys, respectively at 3 wk of age. However, feed consumption was not affected either in broilers or turkeys. Additionally, birds were either not injected or injected with LPS (i.p. 1mg/kg of BW) 24 h prior to tissue and blood collection. Dietary DON had no effect on intestinal crypt depth of broilers and turkeys, but only linearly increased villus height in the mid-ileum of broiler chickens (P=0.04). An interaction was observed between LPS challenge and DON diets in percentage of heterophil, percentage of lymphocyte and heterophil: lymphocyte (H: L) ratios (P<0.05) in broilers but not turkeys. Non-specific phagocytosis by cecal tonsil cells was not affected by DON with or without LPS challenge in both broilers and turkeys. Conversely, antibody dependent phagocytic capacity of cecal tonsil cells to killed S. aureus was significantly reduced over 2.5 fold when broiler chickens were fed highest DON (non-LPS challenged; P ≤ 0.05). However, there was no effect of dietary DON when chicks were challenged with LPS. No effects of dietary DON on phagocytic capacity were observed in turkeys. An additional experiment was conducted to compare growth recovery after a LPS-induced acute phase response (APR) between two broiler strains. The experiment was designed with 3 treatments per strain: an unchallenged positive control (PC), LPS-challenged negative control (LPS-NC), and an unchallenged treatment that was pair-fed to LPS-NC. The LPS was injected at 7, 9, 11, 13 d of age (1mg/kg of BW). The LPS challenge depressed BW at 14 d of age by 10% and 12% for Strains 1 and 2, respectively. However, 67 and 74% of growth depression for Strains 1 and 2, respectively, was attributable to factors other than feed intake reduction when compared with the pair-fed treatment. No BW differences between strains were apparent at the end of the challenge period (14 d; P > 0.05); whereas Strain 1 was 5.4% heavier (153.9 g) at 40 d of age (P < 0.0001). At 40 d of age, birds given the LPS treatment for Strain 1 demonstrated compensatory growth; whereas those for Strain 2 did not. These experiments suggest that graded concentrations of dietary DON had effects on poultry performance, intestinal morphology and innate immunity. Furthermore, growth recovery after an APR was different between and within broiler strains.

Degree

M.S.

Advisors

Applegate, Purdue University.

Subject Area

Animal sciences

COinS