Integrated adrenal, somatotropic, and immune responses of growing pigs to treatment with lipopolysaccharide.

Abstract

The objective of this research was to provide an integrated look at systemic adrenal, somatotropic, and immune responses of growing pigs to challenge with lipopolysaccharide (LPS). Weaned pigs were challenged intraperitoneally with 100 microg/kg BW of LPS or sterile saline, and rectal temperature and blood data were collected for 72 h. Daily feed intake also was monitored. Plasma was analyzed for concentrations of cortisol, tumor necrosis factor alpha (TNFalpha), the acute phase protein haptoglobin, growth hormone (GH), insulin-like growth factor I (IGF-I), and prostaglandin E2 (PGE2). As expected, LPS decreased feed intake, stimulated a febrile response, and activated the hypothalamic-pituitary-adrenal (HPA) axis as demonstrated by increased cortisol levels. Cortisol reached maximum elevation 2 h after treatment (P < .001) and remained elevated through 12 h (P < .001). Circulating TNFalpha was increased by LPS at 2 and 4 h after treatment (P < .001), and an apparent (not statistically significant) increase in haptoglobin also occurred in challenged animals. The LPS injection suppressed IGF-I by 2 h following treatment (P < .01), and circulating IGF-I remained reduced relative to controls through 44 h. Overall, GH was increased in LPS-treated pigs (P < .05), although the treatment x time interaction was not significant. Plasma PGE2 was increased transiently at 2 h (P < .05) and then subsequently suppressed at 4, 8, and 12 h following LPS (P < .05). This study provides a comprehensive view of systemic effects of LPS on components of the HPA, growth, and immune axes. In addition, these are the first data to document changes in circulating PGE2 in unrestrained animals during the early hours of the acute phase response to LPS.

Vitamin E and omega-3 fatty acids independently attenuate plasma concentrations of proinflammatory cytokines and prostaglandin E2 in Escherichia coli lipopolysaccharide-challenged growing–finishing pigs1

“…Interestingly, there was a strong negative correlation between TNF-α and IL-1β concentrations in serum, indicating that LPS-induced immune system stimulation may primarily activate TNF-α rather than IL-1β. However, previous studies showed increased production of both TNF-α and IL-1β after LPS challenge in pigs (Wright et al, 2000;Rakhshandeh and de Lange, 2012). The serotype of E. coli LPS, sampling timing, and dose rate of LPS might have influenced serum concentrations of cytokines and immunity-related molecules, as the response of pigs to LPS was reported to be dose dependent (Webel et al, 1997).…”

“…Disease challenge, whether it is clinical or subclinical, under commercial conditions of pig production can lead to the production of numerous immune system-related compounds such as acute phase proteins (Wright et al, 2000) and cytokines (Curfs et al, 1997;Paradis et al, 2012;Rakhshandeh and de Lange, 2012;Rakhshandeh et al, 2014). The increased release of proinflammatory cytokines in immune system-challenged pigs causes reduced feed intake and growth performance and deterioration in feed efficiency, mainly due to altered nutrient partitioning and neurological infection responses such as anorexia and fever (Webel et al, 1997;Kim et al, 2013).…”

“…The serotype of E. coli LPS, sampling timing, and dose rate of LPS might have influenced serum concentrations of cytokines and immunity-related molecules, as the response of pigs to LPS was reported to be dose dependent (Webel et al, 1997). For example, Wright et al (2000) and Rakhshandeh and de Lange (2012) used LPS extracted from E. coli B55:B5 and used either 100 μg/kg via intraperitoneal injection or 60 μg/kg via intramuscular injection, whereas our study used LPS extracted from E. coli O111:B5 and 30 μg/kg via intramuscular injection. In addition, and from a continuous blood sampling study, Wright et al (2000) showed that a single dose of LPS induced an immune response for only a short period of time (i.e., less than 24 h).…”

“…The physiological response of growing pigs to the LPS challenge is reported to last from only a few hours to 72 h. For example, Wright et al (2000) challenged growing pigs with an intraperitoneal injection of 100 μg E. coli O55:B5 LPS/kg BW and examined changes in plasma concentrations of immunity-related proteins. A single dose of LPS increased plasma levels of TNF-α, PGE 2 , cortisol, growth hormone, and haptoglobin for 4, 4, 16, 48, and 72 h, respectively.…”

DietaryArtemisia ordosicaextract alleviating immune stress in broilers exposed to lipopolysaccharide

“…different animals (Wright et al 2000;Takahashi et al 2003;Yang et al 2011). Our experimental results were consisted with the previous studies.…”