Effects of dietary protein and bacterial lipopolysaccharide infusion on nitrogen metabolism and hormonal responses of growing beef steers1

Abstract

Purified lipopolysaccharide (LPS) infusion in cattle induces clinical and metabolic responses similar to gram-negative bacterial infection. Effects of LPS and dietary protein on rectal temperature, serum hormones, haptoglobin, plasma urea N and AA, and N balance were evaluated in 24 steers (250 +/- 2.8 kg of BW). Treatments were a 2 x 3 factorial of LPS (0 vs. 1.5 microg/kg of BW; -LPS vs. +LPS) and diets containing (DM basis) 1) 14.5% CP, 11.6% ruminally degradable protein (RDP), and 2.9% ruminally undegradable protein (RUP; CP14.5CON); 2) 16.3% CP, 13.4% RDP, and 2.9% RUP (CP16RDP); and 3) 16.1% CP, 11.2% RDP, and 4.9% RUP (CP16RUP). Diet RDP and RUP were altered using casein, fish meal, and corn gluten meal. Steers were adapted to diets (1.1 Mcal/kg of NE(g); DM fed at 1.8% BW) for 14 d and were infused (intravenously 1 mL/min) with LPS (in 100 mL of saline) on d 15. Rectal temperature and serum cortisol, prolactin, haptoglobin, and insulin increased, glucose initially increased and then declined, and serum thyroxine and triiodothyronine decreased for +LPS vs. -LPS steers (LPS x hour; P < 0.01). Serum IGF-I was less (P < 0.01) for +LPS vs. -LPS steers. Plasma urea N increased in response to LPS (LPS x hour; P = 0.02) and was greater for +LPS steers fed CP16RDP and CP16RUP vs. CP14.5CON, but greater in -LPS steers fed CP16RUP vs. CP16RDP and CP14.5CON (LPS x diet; P = 0.04). Plasma Met, Thr, Leu, Ile, Phe, Trp, Gly, Ser, Asn, and Tyr decreased, and plasma Ala increased in response to LPS (LPS x hour; P < 0.01). Plasma Orn initially increased and then decreased in +LPS vs. -LPS steers (LPS x hour; P < 0.01). No LPS x diet interactions (P > or = 0.15) occurred for DM, OM, NDF and N intake, fecal excretion, or apparent digestibility. Dietary DM, OM, NDF, and N intake, and retained N were less (P < 0.01) for +LPS than -LPS steers. Total N intake, apparent N digestibility, and retained N were greater (P < or = 0.05) for steers fed CP16RDP and CP16RUP vs. CP14.5CON. An LPS x diet interaction (P = 0.05) occurred for N retention (% N intake) because N retention was less for +LPS than -LPS steers when fed CP14.5CON, but not different between +LPS and -LPS steers when fed CP16RDP and CP16RUP. These results demonstrate that LPS infusion alters serum hormones, plasma AA, and N balance in cattle and imply that growing steers exposed to LPS may require greater dietary protein concentrations to account for altered intake and metabolic AA demand.

Effects of lipopolysaccharide on the growth performance, nitrogenmetabolism and immunity in preruminant calves

“…This increase in rectal temperature indicated that the LPS elicited a stress response. Similar increases in rectal temperature have been observed in response to LPS challenge in adult cattle (Waldron et al, 2003) and growing heifers 250kg weight (Waggoner et al, 2009a).…”

Effects of dietary lipid sources on performance and apparent total tract digestibility of lipids and energy when fed to nursery pigs1

“…Dibner and Knight (2008) stated that oxidative stress in the gastrointestinal system is associated with loss of barrier function. Failure of the intestinal barrier can increase bacteria translocation (Walker and Sanderson, 1992) and subsequently increase protein degradation (Waggoner et al, 2009) and reduce feed intake (Elsasser et al, 1995;Steiger et al, 1999). Figure 1 shows the relation of calculated initial PV (the percentage of lipid source included in the dietary treatment times the initial PV of the source) and ADG.…”

DietaryArtemisia ordosicaextract alleviating immune stress in broilers exposed to lipopolysaccharide

“…Generally, the inflammatory response is a hallmark of immune stress. Previous studies have reported that the proinflammatory cytokines (IL-1, IL-6, TNF-a) can reduce the utilisation rate of nutrients (Feingold et al 2008;Waggoner et al 2009), and inhibit the growth performance (Sijben et al 2001). In this study, LPS injection significantly increased the contents of serum IL-1, IL-2 and IL-6, meanwhile, diet supplemented with AOE significantly reduced the serum content of IL-2 (on d 21) and IL-6 (on d 28); there was an interaction on IL-1 in broilers between LPS and AOE.…”