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

INVESTIGAŢII PRIVIND LIMITA DE TOLERANŢĂ PENTRU ZEARALENONA ÎN FURAJUL DESTINAT PURCEILOR DUPĂ ÎNŢĂRCARE

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

Rezumat
   Micotoxinele se numara printre cei mai frecventi si mai cunoscuti contaminanti naturali ai cerealelor cu efecte toxice demonstrate atat la animale cat si la om. Cu toate acestea pentru micotoxinele produse de specii de Fusarium exista doar recomandari privind limitele de toleranta pentru furajele destinate animalelor de ferma nefiind inca stabilite norme. Este nevoie de studii suplimentare pentru a vedea daca dozele recomandate nu produc efecte la nivel genetic si imun. Intr-un studiu pe tineret porcin a fost investigat efectul imunotoxic si genotoxic a 100 ppb de zearalenona (recomandarea CE/576/2006). Experimentul a fost realizat pe 12 de purcei hibrizi intarcati (6 purcei/lot) cu o greutate medie iniţiala de 9,83 ± 0.4 kg, timp de 33 de zile. Animalele au fost repartizate in doua loturi si hranite cu furaj fara ZEA (control) si cu furaj contaminat cu 100 ppb ZEA (experimental). La sfarsitul experimentului, animalele au fost sacrificate si s-au recoltat probe de organe pentru evalaurea efectului zearalenonei asupra unor markeri specifici ai inflamatiei, stresului oxidativ si cailor de semnalizare care reglementeaza aceste procese metabolice utilizand tehnicile de qPCR si ELISA. Rezultatele au aratat ca 100 ppb de ZEA descreste expresia genelor care codifica pentru markerii implicati in inflamatie si stres oxidativ, dar fara diferente semnificative fata de control. Diferente nesemnificative au fost observate si la nivelul concentratiei de proteine corespunzatoare acestor markeri. Rezultatele obtinute sugereaza ca nivelul de 100 ppb ZEA poate fi asimilată ca normă (reglementare) de toleranta in furajul purceilor tineri. Coroborarea cu analiza unor markeri implicati in alte procese metabolice importante este necesară.

Cuvinte cheie: porc, zearalenona, norme, imunotoxicitate, genotoxicitate