Fusariotoxins are frequently existing contaminants in cereal and other plant products. High relationship was found between the levels of the trichothecene T-2 and HT-2 toxin detected in contaminated commodities. Many in vitro studies investigated the cytotoxicity of T-2 and HT-2, but the interaction between them has not been thoroughly studied yet. The aim of the study was to examine the dose dependent cytotoxic effect of T-2 and HT-2 toxins, single and in combination, using pig lymphocytes in the methyl thiazol tetrazolium (MTT ) assay. The mycotoxins were added at various concentrations, i.e. 0.5, 0.1, 0.05, 0.01 and 0.001 μM of T-2; 1.0, 0.5, 0.2., 0.1 and 0.05 μM of HT-2; and both mycotoxins combined. Two exposure times (6 and 24 h) were tested. Both T-2 and HT-2 toxins exerted a dose dependent effect. After 6 h incubation, the increase in concentration of T-2 from 0.001 to 0.5 μM and HT-2 for 0.05 to 1.0 μM resulted in lower cell viability by 22 and 17%, respectively. After 24 h cell viability was significantly lower compared to values obtained at 6 h, except 0.5 μM T-2 and 0.05, 1.0 μM HT-2, respectively. Measured cell viability for combinations of T-2 and HT-2 was higher compared to the calculated expected values. The two toxins caused lower cell survival when applied together than in single administration after 6 h incubation. After 24 h incubation this tendency was not consistent.

Oligosaccharide-based prebiotics, like inulin, are intensively examined as alternatives for antibiotic s in rabbits. The aim of the present experiment was to s tudy the effect of dietary supplementation with inulin on the caecal microflora, fibrolytic activit y, and production of volatile fatty acids. Pannon W hite rabbits (n=180) were divided into three groups at w eaning (28 th day of age) and fed ad libitum. Experimental diets were already fed one week before weaning. The control group (C) was fed a standard basal diet with no supplementation; group M received the same but medicated (1 mg/kg diclazuril, 500 mg/kg oxytetracycline and 50 mg/kg tiamulin) diet, while 4% inulin (Frutafit, HD, Brenntag, Budapest) at the expense of barley was ad ded into the diet of the Inulin (I) group. The diet s were similar in the level of crude protein, fat and fibre fractions, while diet I differed in starch a nd sugar content. At 28, 35 and 42 days of age, 6 heal thy animals from each group were randomly selected and caecal microflora and fermentation pat tern were examined. Body weight (BW) at the age of 28 and 35 days was not significantly different, but at 42 d of age a lower (P<0.05) LW was measured in group I. Considering the whole experimental period the weight gain (36±13 g/day) was the smallest and the feed conversion was the greate st (2.46±0.46 g/g) in group I. The incidence of diarrhoea was 1, 2 and 6 in groups C, M and I, resp ectively. Caecal pH was below 7.0 already at weaning and no significant difference between groups was detected. There was a temporary increase in the number of E. coli in each group at 35 days of age, but thereafter it decreased except in group I. The highest cellulase activity was found in the con trol group, while the lowest in the medicated rabbits. On the 35 th d of age the greatest activity of xylanase and cel lulase was detected in group M, while on day 42, the highest xylanase was found in the control group. Concentration of total VFA decreased in group C and M at 35 days of age, after that it increased except group I, where the decrease was observed at 42 days of age. The highes t acetic acid and lowest butyric acid ratio (7%) were found in group I on the 42 nd day. Based on our results, a dietary inclusion wit h inulin does not improve the zootechnical performances or enhance the caecal environment.

The absorption, distribution and elimination of fumonisin B1 (FB1) and its metabolites was investigated in pigs. For the determination of the absorption and biotransformation of FB1, T-cannula were implanted into the distal part of experimental pigs’ ileum and the total urine and faeces moiety was collected during the toxin feeding (45 mg FB1/kg diet, duration: 10 days) and in the subsequent elimination period (10 days). At the end of trial several organs, muscle and fat samples were also collected. The accumulative absorption of fumonisin B1 was 4%. In the chymus, the FB1 conversion to aminopentol (totally hydrolysed FB1; AP1) and partially hydrolysed FB1 (PHFB1) was 1% and 3.9%, respectively. Derivatives of FB1 were mostly accumulated in the liver and kidney, while in negligible concentration could be detected in the muscle and fat samples. In the organs the efficacy of the FB1 to AP1 and PHFB1 conversion was 30% and 20%, respectively. In the faecal content the main hydrolised product was PHFB1 (47%), with 12% of AP1. 1.5% of the FB1 quantity taken up was excreted with the urine, about 35% in hydrolyzed form. Detectable amounts of FB1 and its metabolites were measured in most of the organs, in faeces and urine even 10 days after the feeding of the noncontaminated diet. As a general conclusion, the intestinal microbiota of pigs is able to transform the intact FB1 to a similarly toxic substance (partially hydrolyzed FB1) or to a more toxic metabolite (aminopentol).

The authors investigated the effect of swine ileal and caecal microbiota on fumonisin B-1 (FB1) metabolism. In order to determine the absorption and biotransformation of FB1, T-cannula was implanted into the distal part of pigs' ileum and the total quantity of urine and faeces was collected during the feeding of diet containing toxin (45 mg FB1/kg, for 10 days) and thereafter (for 10 days). At the end of the trial several organs, muscle and fat samples were also collected. It could be established that the accumulative absorption of fumonisin B-1 was 4%. In the chymus, the FB1 conversion to aminopentol (AP(1)) and partially hydrolysed FB1 (PHFB1) was 1% and 3.9%, respectively. In the faecal content the main product was PHFB1 (47%), with small amount (12%) of AP(1). In the examined tissues the efficacy of the FB1 conversion to aminopentol and partially hydrolysed FB1 was 30% and 20%, respectively. in the in vitro study, suspensions of caecal contents, McDougall buffer and pure FB1 (5 mu g/ml) were incubated under anaerobic conditions for 0, 12, 24, 48(th) and 72 hours. In the 48 hours, the conversion of FB1 into PHFB1 (46%) was nearly equal to the percentile ratio of FB1, while in the 72(nd) hours it was 49%. In vitro, the conversion of fumonisin B-1 to AP(1) was less than 1%. Summarized, the intestinal microflora of pigs is able to transform the intact FB1 to a similarly toxic substance (PHFB1) or a more toxic metabolite (AP(1)).

There is a lack of information on the effect of swine caecal microbiota on fumonisin metabolism. In this in vitro study, the biotransformation of fumonisin B(1) (FB(1)) by the gut microbiota of adult, healthy pigs was examined. Suspensions of caecal contents and McDougall buffer solution were incubated anaerobically with pure FB(1) for 0, 12, 24, 48 and 72 h. After 48 h, the conversion of FB(1) to partially hydrolysed FB(1) (46%) was nearly equal to the percentage ratio of FB(1), while by 72 h it was 49%. In vitro, the conversion of fumonisin B(1) to aminopentol was less than 1%. The results show that the caecal microbiota are capable of transforming fumonisin B(1) to the above metabolites. Further studies on FB(1) metabolism in the small intestine are clearly justified.

D-amino acids occurring in dietary proteins originate as a consequence of technological intervention while basic materials are being prepared for consumption. Foodstuffs are the most significant sources of D-amino acids, as in the process of cooking or during the various processing procedures used in the food industry dietary proteins undergo racemisation to a greater or lesser degree. Food stores are now selling increasing quantities of foods (such as breakfast cereals, baked potatoes, liquid and powdered infant foods, meat substitutes and other supplements) which in some cases contain substantial quantities of D-amino acids, which in turn possess characteristics harmful with respect to digestion and health. Alkali treatment catalyses the racemisation of optically active amino acids. The degree of racemisation undergone varies from protein to protein, but the relative order of the degree of racemisation of the individual amino acids within proteins shows a high level of similarity. The principal factors influencing racemisation are the pH of the medium, heat treatment, the duration of the application of alkaline treatment and the structure of the respective amino acids. D-amino acids formed in the course of treatment with alkalis or heat give rise to a deterioration in quality and reduce the extent to which food thus treated can be used safely. The presence of D-amino acids in proteins leads to a decrease in digestibility and the availability of the other amino acids. This results in a reduction in the quantities of the L-enantiomers of the essential amino acids, as the peptide bonds cannot split in the normal way. Some D-amino acids can exert an isomer-toxic effect and have the capacity to give rise to changes in the biological effect of lysinoalanine.

Synthesis of Plagiochins A and B, Macrocyclic Bis(bibenzyl) Ethers from Plagiochila acantophyllaPlagiochins A (1) and B (2), macrocyclic bis(bibenzyl) ethers with a 16‐membered ring, are synthesized. The key steps are the Pd(0)‐catalyzed C—C coupling of an areneboronic acid (18) with an aryl bromide with formation of a biphenyl (13), Ullmann ether synthesis of a diphenyl ether (23), Wittig reaction to connect the two components 13 and 23, and a modified Wurtz reaction to close the ring. The latter reaction is accompanied by an unusual transformation of a C‐benzyloxy to a C‐benzoyl group.