Exposure assessment of dogs to mycotoxins through consumption of dry feed.

BACKGROUND: The Brazilian exportation of pet food has shown high growth rates in the last two years and determination of the exposure degree is one of the most important parameters for the risk assessment of chemical compounds. In this study the exposure degree of dogs to mycotoxins was estimated and acceptable daily intake (ADI) and safe pet dietary level (SPDL) were calculated. Thus the natural occurrence of fumonisins, zearalenone and aflatoxins was evaluated in 100 dry dog feed samples provided by pet owners in Paraná State, Brazil. RESULTS: Despite the high frequency of fumonisins (68%), zearalenone (95%) and aflatoxins (68%) in feed samples, the mean levels detected were low. ADI for fumonisins and zearalenone was 20.0 and 1.00 µg kg(-1) body weight (BW) day(-1) respectively and SPDL for fumonisins was 2000 µg kg(-1) feed. The probable daily intake values (1.83 µg fumonisins, 0.93 µg zearalenone and 0.02 µg aflatoxins kg(-1) BW day(-1) ) were low. CONCLUSION: The exposure degree of dogs could be assumed to be very low. However, the co-occurrence of these three or other mycotoxins, and possible synergic or additive effects, should be taken into account when determining the maximum allowed levels or risk assessment. © 2016 Society of Chemical Industry.

Effect of fungicide on Fusarium verticillioides mycelial morphology and fumonisin B1 production.

The effect of fludioxonil + metalaxyl-M on the mycelial morphology, sporulation and fumonisin B 1 production by Fusarium verticillioides 103 F was evaluated. Scanning electron microscopy analysis showed that the fungicide caused inhibition of hyphal growth and defects on hyphae morphology such as cell wall disruption, withered hyphae, and excessive septation. In addition, extracellular material around the hyphae was rarely observed in the presence of fludioxonil + metalaxyl-M. While promoting the reduction of mycelial growth, the fungicide increased sporulation of F. verticillioides compared to the control, and the highest production occurred on the 14 (th) day in the treatments and on the 10 (th) day in the control cultures. Fumonisin B 1 production in the culture media containing the fungicide (treatment) was detected from the 7 (th) day incubation, whereas in cultures without fungicide (control) it was detected on the 10 (th) day. The highest fumonisin B 1 production occurred on the 14 (th) day, both for the control and for the treatment. Fludioxonil + metalaxyl - M can interfere in F. verticillioides mycelial morphology and sporulation and increase fumonisin B 1 levels. These data indicate the importance of understanding the effects of fungicide to minimize the occurrence of toxigenic fungi and fumonisins.

Effect of fungicide on Fusarium verticillioides mycelial morphology and fumonisin B1 production

The effect of fludioxonil + metalaxyl-M on the mycelial morphology, sporulation and fumonisin B1 production by Fusarium verticillioides 103 F was evaluated. Scanning electron microscopy analysis showed that the fungicide caused inhibition of hyphal growth and defects on hyphae morphology such as cell wall disruption, withered hyphae, and excessive septation. In addition, extracellular material around the hyphae was rarely observed in the presence of fludioxonil + metalaxyl-M. While promoting the reduction of mycelial growth, the fungicide increased sporulation of F. verticillioides compared to the control, and the highest production occurred on the 14th day in the treatments and on the 10th day in the control cultures. Fumonisin B1 production in the culture media containing the fungicide (treatment) was detected from the 7th day incubation, whereas in cultures without fungicide (control) it was detected on the 10th day. The highest fumonisin B1 production occurred on the 14th day, both for the control and for the treatment. Fludioxonil + metalaxyl - M can interfere in F. verticillioides mycelial morphology and sporulation and increase fumonisin B1 levels. These data indicate the importance of understanding the effects of fungicide to minimize the occurrence of toxigenic fungi and fumonisins.