INVESTIGATION OF ZEARALENONE TOLERANCE LIMIT IN THE FEEDSTUFFS FOR WEANED PIGS

Ionelia Taranu, M.A. Gras, Gina Cecilia Pistol, Monica Motiu, Daniela Marin, Mariana Stancu

Abstract
   In the present study an in vivo feeding experiment was carried out to evaluate the immunotoxic and genotoxic effect of a diet contaminated with 100 ppb zearalenone (the maximal tolerance level recommended by CE/576/2006) in young pigs. Six weaned pigs received the diet contaminated with 100 ppb of zearalenone (ZEA), while other six pigs receiving a non-contaminated diet were used as control for 33 days. The effect of ZEA on pro-inflammatory cytokines and several molecules involved in oxidative stress (CAT, SOD, GPx, iNOS, eNOS) and related pathways (NF-kB1, p38-MAPK, Nrf2) was investigated in internal organs (liver, spleen, kidney and intestine) collected at the end of the experiment. Real-time PCR and ELISA analyses were used to perform gene expression and protein concentration of the above mentioned markers.
   Our qPCR results showed that the level of 100 ppb of ZEA in the pig diet decreased the gene expression of markers involved in inflammatory process in intestine (duodenum) and liver, but not in spleen, kidney and colon in which an increase in the expression of these genes was found. The modulation of gene expression was not statistically different for the majority of pro-inflammatory cytokines compared to control. Also, throughout ELISA analyses no differences were detected at the protein level for these markers. However, a significant difference was found in gene expression for IL-8 in spleen (+320%) and duodenum (-89%), IL-6 in spleen (+127%) and kidney (+120%) and for COX2 in liver (-88%) and colon (+279%) respectively, when compared to control. Gene encoding for enzymes involved in the oxidative stress were affected (up-regulation) especially in liver and kidney and less in the other organs.
   The corroboration of these results with other markers of metabolic and physiological processes might contribute to the establishment of the dose accepted as maximal limits in the diet designated to young pigs.

Key words: zearalenone, pig, limit of tolerance