Effect of chronic T-2 toxin exposure in rabbit bucks, determination of the No Observed Adverse Effect Level (NOAEL).

T-2 toxin (T-2) was administered to adult Pannon White (n = 10/group) male rabbits for 65 days, first in a suspension by gavage (0.05, 0.1 or 0.2 mg/animal/day), and secondly mixed into the feed (0.33 and 0.66 mg/kg feed). In the first experiment 0.1 mg T-2 exposure resulted in temporary decrease in feed intake, slower increase in the gonadotropin-releasing hormone (GnRH) induced testosterone synthesis, slight centrolobular infiltration in the liver and a slight hyperplasia of the Leydig cells. In addition to the temporary feed refusal effect, 0.2 mg T-2 caused a temporary decrease in plasma albumin and urea concentrations, lesser glutathione peroxidase (GPx) activity in the seminal plasma, a greater (by 320%) ratio of spermatozoa with cytoplasmic droplets, slower increase in the GnRH-induced testosterone synthesis, centrolobular infiltration in the liver, slightly hyperaemic testes and increased proliferative activity of the Leydig cells. The two smaller doses applied in feed (0.33 and 0.66 mg/kg) did not cause any significant adverse effect, and no feed refusal was observed. According to these results the No Observed Adverse Effect Level (NOAEL) of T-2 for adult rabbit males was found to be <0.1 mg/animal/day (<0.02 mg/kg b.w./day).

The cytotoxic effect of fumonisin B1 and ochratoxin A on human and pig lymphocytes using the Methyl Thiazol Tetrazolium (MTT) assay.

Lymphocytes cell obtained from healthy human donors and pigs were exposed to fumonisin B1 (FB1) and ochratoxin A (OTA), which have been found to be immunosuppressive, carcinogenic and mutagenic, to ascertain their single and combined cytotoxic effects with time and to assess the suitability of animal lymphocytes as test agents in comparison to human cells. The main objectives of this work were to assess the use of animal lymphocytes, particularly pig lymphocytes, for their use in the Methyl Thiazol Tetrazolium (MTT) cytotoxicity test, making them more accessible to animal research-based institutes in comparison to human lymphocytes previously used, and to study the cytotoxic and synergism or antagonistic effects of FB1 and OTA. The MTT assay, which measures cell viability and proliferation based on reduction of MTT to a blue dye, also used the addition of phytohaemagglutinin (PHA) to stimulate the blood cells. The results showed a progressive decrease in lymphocytes viability with time of exposure to the toxins. It was also noted that FB1, as compared to OTA, had a lower cytotoxicity on both human and pig lymphocytes cells. In addition, when the two mycotoxins were combined, a synergistic decrease of cell viability in both human and pig lymphocytes was observed, with pig lymphocytes showing a greater sensitivity. This study has shown that the MTT assay can be used for the determination of cytotoxicity of mycotoxins using animal, and in particular pig, lymphocytes, which eliminates the use of human donors and other cell cultures.