Does Dietary Deoxynivalenol Modulate the Acute Phase Reaction in Endotoxaemic Pigs?—Lessons from Clinical Signs, White Blood Cell Counts, and TNF-Alpha

Abstract

We studied the interaction between deoxynivalenol (DON)-feeding and a subsequent pre- and post-hepatic immune stimulus with the hypothesis that the liver differently mediates the acute phase reaction (APR) in pigs. Barrows (n = 44) were divided into a DON-(4.59 mg DON/kg feed) and a control-diet group, surgically equipped with permanent catheters pre- (V. portae hepatis) and post-hepatic (V. jugularis interna) and infused either with 0.9% NaCl or LPS (7.5 µg/kg BW). Thus, combination of diet (CON vs. DON) and infusion (CON vs. LPS, jugular vs. portal) created six groups: CON_CONjug.-CONpor., CON_CONjug.-LPSpor., CON_LPSjug.-CONpor., DON_CONjug.-CONpor., DON_CONjug.-LPSpor., DON_LPSjug.-CONpor.. Blood samples were taken at −30, 15, 30, 45, 60, 75, 90, 120, 150, 180 min relative to infusion and analyzed for leukocytes and TNF-alpha. Concurrently, clinical signs were scored and body temperature measured during the same period. LPS as such induced a dramatic rise in TNF-alpha (p < 0.001), hyperthermia (p < 0.01), and severe leukopenia (p < 0.001). In CON-fed pigs, an earlier return to physiological base levels was observed for the clinical complex, starting at 120 min post infusionem (p < 0.05) and persisting until 180 min. DON_LPSjug.-CONpor. resulted in a lower temperature rise (p = 0.08) compared to CON_LPSjug.-CONpor.. In conclusion, APR resulting from a post-hepatic immune stimulus was altered by chronic DON-feeding.

Relationships between body temperatures and inflammation indicators under physiological and pathophysiological conditions in pigs exposed to systemic lipopolysaccharide and dietary deoxynivalenol

“…Experimental design (upper panel, from (Bannert et al., ; Tesch et al., )) as well as the pattern of blood sampling and rectal temperature measurement (lower panel)…”

“…This crucial difference between both entry sites highlights the role of the liver as a major metabolising organ, also for xenobiotics such as LPS. Previously published data have already shown an impact of DON‐feeding and LPS infusion on clinical signs, fever response in body core temperature, leucocyte counts and TNF‐ α (Tesch et al., ). In addition to these published results, we complemented our data with measurement of rectal temperature and kynurenine–tryptophan analyses.…”

“…In pathophysiological conditions, such as lipopolysaccharide (LPS)‐induced acute endotoxaemia or chronic mycotoxin exposure, the organism initiates an immune response. To eliminate the pathogenic agents rapidly, self‐regulatory mechanisms get impaired causing a dysregulation of homoeostasis in several body functions, for example body temperature, white blood cell counts (WBC counts) and blood gases, (Bannert et al., ; Tesch et al., ). While acute internal restoration processes to LPS are accompanied by clinically observable indicators of an immune response, such as the cardinal symptom fever, immune responses to chronic mycotoxin deoxynivalenol (DON) often comprise slowly initiated and less obvious modifications in different parameters, such as leucocyte counts (Tesch et al., ).…”

“…In addition, the mycotoxin DON stimulates the immune system when provided in a chronic manner, as proven by increased leucocyte counts, and alters the organism's acute immune response to LPS‐induced endotoxaemia, mirrored in modifications of clinical symptoms (Tesch et al., ). However, continuous measurement of WBC counts is not always routine; thus, chronic DON exposure often remains undetected although this provokes economic losses (e.g., reduced weight gain) in pigs.…”

“…Therefore, in case of pathophysiological conditions, changes in body core homoeostasis may not be reflected entirely in rectally measured temperature and inflammatory blood parameters, thus evaluating porcine health status incorrect. To investigate the nature of the relationship between body temperatures under physiological (clinically inconspicuous) as well as under combined acute and chronic pathophysiological conditions, we used an experimental model described earlier (Tesch et al., ), contrasting pigs chronically pre‐exposed with DON to control‐fed pigs under clinically inconspicuous and acute endotoxaemic conditions. The latter was induced either via the jugular or portal vein and those different LPS‐entry sites attempted to create two endotoxaemic conditions in both feeding groups based on their liver passage.…”