Osselaere A., M. Devreese, A. Watteyn, V. Vandenbroucke, J. Goossens, V. Hautekiet, M. Eeckhout, S. De Saeger, S. De Baere, P. De Backer, and S. Croubels

Contamination of feeds with mycotoxins is a worldwide problem and mycotoxin-detoxifying agents are used to decrease their negative effect. The European Food Safety Authority recently stated guidelines and end-points for the efficacy testing of detoxifiers. Our study revealed that plasma concentrations of deoxynivalenol and deepoxy-deoxynivalenol were too low to assess efficacy of 2 commercially available mycotoxin-detoxifying agents against deoxynivalenol after 3 wk of continuous feeding of this mycotoxin at concentrations of 2.44±0.70 mg/kg of feed and 7.54±2.20 mg/kg of feed in broilers. This correlates with the poor absorption of deoxynivalenol in poultry. A safety study with 2 commercially available detoxifying agents and veterinary drugs showed innovative results with regard to the pharmacokinetics of 2 antibiotics after oral dosing in the drinking water. The plasma and kidney tissue concentrations of oxytetracycline were significantly higher in broilers receiving a biotransforming agent in the feed compared with control birds. For amoxicillin, the plasma concentrations were significantly higher for broilers receiving an adsorbing agent in comparison to birds receiving the biotransforming agent, but not to the control group. Mycotoxin-detoxifying agents can thus interact with the oral bioavailability of antibiotics depending on the antibiotic and detoxifying agent, with possible adverse effects on the health of animals and humans.

Awad, W. A., J. Bohm, E. Razzazi-Fazeli, K. Ghareeb, and J. Zentek

An experiment was conducted to study the effects of deoxynivalenol (DON) on the performance of broilers, organ weights, and intestinal histology and to evaluate the efficacy of a probiotic feed additive (PB, Eubacterium sp.) with the ability to deepoxidize DON. Two hundred seventy-seven 1-d-old broiler chicks were randomly assigned to 1 of the 3 dietary treatments for 6 wk. The dietary treatments were 1) control; 2) artificially contaminated diets with 10 mg of DON/kg of diet; 3) DON-contaminated diets plus probiotic feed additive (DON-PB). The BW and the efficiency of feed utilization were not adversely affected (P > 0.05) by the inclusion of DON in the diets. A slight improvement in feed intake and BW gain over the course of the experiment was observed in broilers fed DON-PB with no change in feed efficiency. The absolute or relative organ weights were not altered (P > 0.05) in broilers fed the diet containing DON compared with controls and the DON-PB group. The absolute liver weights were numerically increased (P < 0.1) for broilers receiving the diet containing DON-PB. There were no significant differences in the absolute and relative weights of the gizzard, duodenum, pancreas, heart, and spleen. However, the absolute and relative weights of the jejunum and cecum were increased for DON-PB-fed broilers compared with the controls and DON group. No pathological lesions were found in the gut of birds fed DON-contaminated diets during the feeding trial, but mild intestinal changes were observed. The DON altered small intestinal morphology, especially in the duodenum and jejunum, where villi were shorter and thinner (P < 0.05). The addition of the eubacteria to the DON-contaminated feed of the broilers effectively alleviated the histological alterations caused by DON and led to comparable villus length as in the control group. In conclusion, diets with DON contamination below levels that induce a negative impact on health and performance could affect small intestinal morphology in broilers. The histological alterations caused by DON were reduced by supplementing the DON-containing diets with PB. This indicates that in case of DON contamination of feedstuffs, the addition of PB would be a proper way to counteract the possible effects caused by this mycotoxin.

Diaz, G. J., A. Cortes, and L. Roldan

The possible protective effect of 4 feed additives against the toxic effects of T-2 toxin in growing broiler chickens was investigated in a 28-d fully randomized trial consisting of 6 dietary treatments (control with no T-2 toxin or feed additive added, 2 ppm T-2 toxin alone, 2 ppm T-2 toxin plus 2.0 g/kg Mycofix, 2 ppm T-2 toxin plus 2.0 g/kg Mycosorb, 2 ppm T-2 toxin plus 2.5 g/kg MycoAd, and 2 ppm T-2 toxin plus 3.0 g/kg Zeolex). When no feed additive was included, 2 ppm dietary T-2 toxin significantly decreased BW and increased feed:gain ratio. When 2.0 g/kg Mycofix were added to the diet, the feed additive protected against the adverse effects of T-2 toxin on BW, BW gain, and feed:gain ratio; however, no protection against the adverse effects of T-2 toxin on final BWandBWgain were obtained by supplementation of any of the other 3 feed additives.Asignificant increase in relative gizzard weight was observed in chicks fed 3 of the additives (Mycosorb, MycoAd, and Zeolex) but not in those fed T-2 toxin alone or combined with Mycofix. Chicks supplemented with Zeolex plus T-2 toxin had a significantly decreased aspartate aminotransferase serum activity compared with controls. The results of the present trial indicate that the only feed additive capable of counteracting the adverse effects on performance caused by the dietary administration of 2 ppm T-2 toxin was the additive based on the enzymatic inactivation of the 12,13-epoxide ring of the trichothecenes (Mycofix). This study also confirms previous reports showing that aluminosilicates are not effective against trichothecene mycotoxins.

This investigation was conducted in order to investigate the efficacy of the detoxifying agent Mycofix® Plus (MP) in the prevention and/or alleviation in vivo adverse effects of T-2 toxin in broilers. In addition, the adsorbing potential of MP was estimated in vitro. Mean degradation levels of T-2 toxin with MP in vitro, as measured by HPTLC, varied from 26.06 to 31.02 % and the adsorption ability was elevated in acidic environment (pH 3). In vivo trial was performed on 160 one day old "Ross" broiler chicks and lasted for 21 days. Birds were divided into 4 equal groups as follows: Group 1 - negative control; Group 2 - positive control - 2 ppm T-2 toxin; Group 3 - 2 ppm T-2 toxin+2 kg/t MP; Group 4 - 2 kg/t MP. Broilers fed the diet containing 2 mg/kg of T-2 toxin without MP developed typical T-2 toxicosis. Birds that were fed the diet containing both T-2 and MP had better performances and no oral ulcerations as the dominant sign of T-2 toxicosis were observed. Histopathological examination of tissues originating from birds fed the diet containing T-2 toxin revealed degenerative changes in the oral and small intestine mucosa, necroses of enterocytes and hepatocytes, as well as depletion of lymphocytes in the bursa Fabricii. Immunohistochemical examination also revealed negative effects of T-2 toxin on cells proliferation in intestineal and bile duct mucosa, as well as on lymphocytes from bursa Fabricii. The macroscopic and microscopic structure of the liver, intestine and bursa Fabricii of broilers fed a diet containing T-2 toxin and MP was mostly preserved. Cutaneous basophile hypersensitivity reaction was weaker in broilers fed mixtures containing 2 mg/kg T-2 toxin.

Murugesan, G. R., D. R. Ledoux, K. Naehrer, F. Berthiller, T. J. Applegate, B. Grenier, T. D. Phillips, and G. Schatzmayr

Extensive research over the last couple of decades has made it obvious that mycotoxins are commonly prevalent in majority of feed ingredients. A worldwide mycotoxin survey in 2013 revealed 81% of around 3,000 grain and feed samples analyzed had at least 1 mycotoxin, which was higher than the 10-year average (from 2004 to 2013) of 76% in a total of 25,944 samples. The considerable increase in the number of positive samples in 2013 may be due to the improvements in detection methods and their sensitivity. The recently developed liquid chromatography coupled to (tandem) mass spectrometry allows the inclusion of a high number of analytes and is the most selective, sensitive, and accurate of all the mycotoxin analytical methods. Mycotoxins can affect the animals either individually or additively in the presence of more than 1 mycotoxin, and may affect various organs such as gastrointestinal tract, liver, and immune system, essentially resulting in reduced productivity of the birds and mortality in extreme cases. While the use of mycotoxin binding agents has been a commonly used counteracting strategy, considering the great diversity in the chemical structures of mycotoxins, it is very obvious that there is no single method that can be used to deactivate mycotoxins in feed. Therefore, different strategies have to be combined in order to specifically target individual mycotoxins without impacting the quality of feed. Enzymatic or microbial detoxification, referred to as "biotransformation" or "biodetoxification," utilizes microorganisms or purified enzymes thereof to catabolize the entire mycotoxin or transform or cleave it to less or non-toxic compounds. However, the awareness on the prevalence of mycotoxins, available modern techniques to analyze them, the effects of mycotoxicoses, and the recent developments in the ways to safely eliminate the mycotoxins from the feed are very minimal among the producers. This symposium review paper comprehensively discusses the above mentioned aspects.

Xue, C. Y., G. H. Wang, F. Chen, X. B. Zhang, Y. Z. Bi, and Y. C. Cao

The purpose of this study was to investigate the immunopathological effects of combinations of ochratoxin A (OTA) and T-2 toxin on broilers. Four hundred eighty 1-d-old broilers were randomly assigned to 4 groups, each group consisting of 4 duplicates each with 30 broilers. The 4 groups were fed the following diets for 4 wk: group 1=basal diet (control, mycotoxin-free); group 2=basal diet+2,000 mg/kg of Mycofix Plus; group 3=basal diet+0.25 mg/kg of OTA and 0.5 mg/kg of T-2; and group 4=basal diet+0.25 mg/kg of OTA and 0.5 mg/kg of T-2+2,000 mg/kg of Mycofix Plus. The feeding of OTA-T-2 toxin diets reduced (P<0.05) the level of anti-Newcastle disease virus antibody titers by 10.4%. When broilers were administered lipopolysaccharide, the results of real-time PCR showed that broilers fed OTA-T-2 toxin reduced the cytokine mRNA expression levels of interleukin-2 and interferon-gamma to some extent but not significantly (P>0.05). The concentrations of interleukin-2 and interferon-gamma in serum were significantly decreased (P<0.05) by OTA-T-2 toxin combination. Histopathological studies demonstrated that OTA-T-2 toxin combination caused abnormalities in the thymus, bursa of Fabricius, spleen, and liver. Ochratoxin A-T-2 toxicity could be counteracted by Mycofix Plus partially but not significantly (P>0.05). The concentrations of OTA and T-2 toxin used in this study are under the maximum tolerated levels recommended by Canadian Food Inspection Agency. Our study clearly put the standard and detoxification method for these toxins into question. We suggest that it may be time to reduce the maximum allowable limits of OTA and T-2 mycotoxins in feeds to improve animal health and the safety of the food chain.

Danicke, S., K.-H. Ueberschar I. Halle, S. Matthes, H. Valenta, and G. Flachowsky

16-wk experiment with laying hens was carried out to examine the effects of feeding of mycotoxin-contaminated maize (CM) on performance, nutrient digestibility, weight of organs, serum chemical parameters, and antibody titers to Newcastle disease virus (NDV) in serum. Also tested were fimbrien antigen K88 in egg yolk and zearalenone (ZON) residues in eggs and tissues. The Fusarium-toxin-contaminated maize contained 17,630 microg deoxynivalenol and 1,580 microg ZON/kg. Moreover, Mycofix Plus (MP), a so-called detoxifying agent, was added to both the uncontaminated control (UCM) and to the CM diet (70% dietary maize inclusion). Each of the four resulting diets (UCM, UCM-MP, CM, CM-MP) was tested on 25 laying hybrids (Lohmann Brown). Feeding of the CM diets significantly depressed feed intake compared to the control groups by approximately 5%. This was mainly due to the effects observed at the beginning of the experiment. Daily egg mass production/hen was 56.6, 58.4, 53.9, and 55.2 g in groups UCM, UCM-MP, CM and CM-MP, respectively. Nutrient digestibility and metabolizability of gross energy were slightly depressed by feeding the CM diets and improved by MP addition. Feeding of the CM diets resulted in a significant decrease in serum titers to NDV and to an increase in yolk titers to antigen K88. No residues of ZON or of its metabolites were found in yolk, albumen, abdominal fat, breast meat, follicles greater than 1 cm in diameter, ovaries including follicles smaller than 1 cm in diameter, magnum, and serum. ZON and alpha-zearalenol (alpha-ZOL) were detected in livers of hens fed the CM diets at mean concentrations of 2.1 and 3.7 microg/kg, respectively. It was concluded that feeding maize which was highly contaminated with Fusarium mycotoxins adversely influenced performance of hens and modulated immune response. At the given level of zearalenone and at the indicated detection limits, no residues of ZON and its metabolites were found in eggs. The effects of the tested detoxifying agent were quite mycotoxin-independent.