Effects of surplus dietary L-tryptophan on stress, immunology, behavior, and nitrogen retention in endotoxemic pigs1

Abstract

The possible beneficial effects of surplus dietary Trp (+5 g of Trp/kg of diet) on factors related to stress, immunology, behavior, and N retention were investigated in postweaning piglets (approximately 15 kg of BW) challenged for 10 d with intravenous bacterial lipopolysaccharide (from Escherichia coli). Two diets fed restrictively (732 kJ of NE/kg of BW(0.75)/d) were compared, 1) a basal diet (apparent ileal digestible Trp = 1.9 g/kg; the recommended amount of Trp to warrant near-optimal growth in nonendotoxemic piglets), and 2) a Trp-enriched basal diet (+5 g of free l-Trp/kg), with 8 individually housed piglets per diet. Pooled salivary cortisol, but not plasma cortisol sampled at euthanasia, showed a tendency (P = 0.07) toward reduced concentrations in the Trp group (1.1 vs. 1.4 ng/mL; pooled SE = 0.1 ng/mL). Plasma C-reactive protein was reduced (P = 0.04) in the Trp group (0.9 vs. 5.0 mg/L; pooled SE = 1.3 mg/L), but haptoglobin, IL-6, tumor necrosis factor α, and lipopolysaccharide-induced fever were similar between the 2 dietary treatments. Physical activity related to approaching a human showed a tendency (P = 0.08) toward increased latency time in the Trp group (101 vs. 60 s; pooled SE = 16 s), but the times spent standing, sitting, and lying were similar between dietary treatments. The ADFI, ADG (346 vs. 302 g/d; pooled SE = 14 g/d; P = 0.11), body N retention (11.6 vs. 11.0 g/d; pooled SE = 0.2 g/d; P = 0.18), and G:F (0.55 vs. 0.49; pooled SE = 0.03; P = 0.17) were not different between the groups fed Trp and the basal diet. In conclusion, surplus dietary Trp had limited effects on stress, immunology, behavior, and N retention in a pig model of systemic endotoxemia.

Lipopolysaccharide immune stimulation but not β-mannanase supplementation affects maintenance energy requirements in young weaned pigs

“…Haptoglobin is a primary APP in pigs and is synthesized in the liver when activated by IL-6 and to a lesser extent IL-1 [ 58 ], both of which were significantly elevated in ISS pigs post-challenge. Similar to our results, Koopmans et al [ 55 ] discussed unpublished data which showed no LPS effect on haptoglobin concentrations even though there were clear increases in plasma cortisol, TNFα, IL-6, and C-reactive protein over a 24-h period after LPS challenge. One possible explanation for a lack of haptoglobin response could be time related.…”

“…However, in this study, ISS APP concentrations did not differ compared to CON. This was an unexpected result because LPS has been demonstrated to increase APPs such as haptoglobin [ 8 , 46 ] and C-reactive protein [ 55 ] in pigs. A less responsive APP, MBL has been demonstrated to attenuate LPS-induced pro-inflammatory cytokine production [ 56 ] and inhibit T-lymphocyte activation [ 57 ].…”

Disruption of Epithelial Barrier of Caco-2 Cell Monolayers by Excretory Secretory Products of Trichinella spiralis Might Be Related to Serine Protease

“…The MAPK signaling pathway is a well-known signal transduction pathway that regulates a variety of cellular activities (Peyssonnaux and Eychene, 2001). Importantly, the MAPK pathway plays a critical role in the regulation of intestinal epithelial barrier functions (Koopmans et al, 2011). Studies have shown that some substance can cause the intestinal barrier to be destroyed, thereby increasing the expression of MAPK (Böhringer et al, 2016;Gao et al, 2017).…”

Dietary phytonutrients and animal health: regulation of immune function during gastrointestinal infections

“…During acute immune and inflammatory responses, tryptophan (Trp) is often considered rate-limiting as it is rapidly catabolized by the upregulation of indoleamine 2,3-dioxygenase (IDO1), which accompanies lymphocyte activation. Increasing supply of Trp can potentially enhance immune function in pigs and poultry, although results have been inconsistent (Koopmans et al, 2012;Capozzalo et al, 2015). Similarly, glutamine or threonine supplementation may have the potential to improve innate immunity and maintenance of the gut barrier during coccidiosis or necrotizing enterocolitis in broilers (Wils-Plotz et al, 2013;Xue et al, 2018).…”