Oral exposure of pigs to the mycotoxin deoxynivalenol does not modulate the hepatic albumin synthesis during a LPS-induced acute-phase reaction

Abstract

The sensitivity of pigs to deoxynivalenol (DON) might be influenced by systemic inflammation (SI) which impacts liver. Besides following acute-phase proteins, our aim was to investigate both the hepatic fractional albumin (ALB) synthesis rate (FSR) and the ALB concentration as indicators of ALB metabolism in presence and absence of SI induced by LPS via pre- or post-hepatic venous route. Each infusion group was pre-conditioned either with a control diet (CON, 0.12 mg DON/kg diet) or with a DON-contaminated diet (DON, 4.59 mg DON/kg diet) for 4 wk. A depression of ALB FSR was observed 195 min after LPS challenge, independent of feeding group or LPS application route, which was not paralleled by a down-regulated ALB mRNA expression but by a reduced availability of free cysteine. The drop in ALB FSR only partly explained the plasma ALB concentrations which were more depressed in the DON-pre-exposed groups, suggesting that ALB levels are influenced by further mechanisms. The abundances of haptoglobin, C-reactive protein, serum amyloid A, pig major acute-phase protein, fibrinogen and LPS-binding protein mRNA were up-regulated upon LPS stimulation but not accompanied by increases in the plasma concentrations of these proteins, pointing at an imbalance between synthesis and consumption.

Occurrence of Zearalenone and Its Metabolites in the Blood of High-Yielding Dairy Cows at Selected Collection Sites in Various Disease States

“…However, these differences could be also attributed to unknown factors that cause rumen inflammations, thus increasing the risk of absorption of toxic compounds, such as lipopolysaccharides (major risk factors) and/or mycotoxins, through the rumen wall [ 23 ]. According to Dänicke et al [ 4 , 36 ], low ruminal pH (which compromises the buffering capacity of the rumen, [ 23 ]) inhibits the biotransformation of parent compounds such as ZEN and metabolite synthesis, which could explain the absence of ZEN metabolites in the examined blood samples ( Figure 1 and Figure 2 ). The cited authors also argued that in ruminants, ZEN (parent compound) can be transported to the postruminal digestive tract at unchanged levels and cause mycotoxicosis [ 37 ] or digestive disorders contributing to feed-borne diseases such as mastitis, ovarian cysts and pyometra [ 3 ].…”

“…However, trace amounts of the parent compound were identified in the blood, probably because ZEN is not completely metabolized in the rumen. This mycotoxin is transported to successive intestinal segments in unmodified form, and it reaches peripheral organs with the blood and enters the prehepatic circulation that ends in the portal vein ( vena portae ) which supplies blood to the liver [ 4 , 22 ]. The evaluated herd was probably exposed to ZEN for a long period of time or continuously.…”

“…Metabolic disorders are most frequently observed in three critical periods [ 3 ]: (i) dry period, (ii) parturition, and (iii) first 100 days of lactation. These periods are characterized by an increased risk of udder inflammation and aseptic diffuse inflammation of the laminar corium, which are indicative of compromised innate immunity, decreased acquired immunity to infectious factors [ 4 ], and higher susceptibility to undesirable substances, including secondary metabolites of molds such as ZEN and its metabolites.…”

“…The rumen contents contaminated with mycotoxins may be absorbed in the duodenum, leading to certain mycotoxin concentrations in dairy cows. The clinical symptoms of mycotoxin poisoning are generally non-specific, and they include metabolic and hormonal disorders accompanied by inflammatory states caused by a weakened immune response [ 4 ]. During transition periods, cows are particularly susceptible to mycotoxicosis because the presence of molds and/or mycotoxins in cattle diets further deepens the negative energy balance [ 3 ].…”

“…The main routes of blood inflow and outflow to/from the liver should be examined taking into account the availability of blood vessels and the extent of natural (hepatic) detoxification. Topographic anatomy of anastomoses between the portal venous system ( vena portae ) with the major veins [ 22 ], including the external jugular vein (EJV, v. jugularis externa- posthepatic), the abdominal subcutaneous vein (ASV, v. epigastrica cranialis superficialis -prehepatic) and the median caudal vein (MCV, v. caudalis mediana -prehepatic) should be analyzed to confirm the reliability and consistency of the results [ 4 ].…”