Occurrence of Fusarium species and their mycotoxins in corn silage. 5. Fusarium infestation in corn silage

The internal mycoflora of silage maize plants was examined in several years. Average Fusarium infection of the maize plants was 10.4% and leaf sheaths and stalks were preferably colonized by the fungi. During the growing season an increase in total colonization of the maize plant by field fungi as well as by species of the genus Fusarium was observed 17 different Fusarium species were isolated from silage maize plants. Most frequently occurring species (more than 85%) in descending order were F. avenaceum, F. culmorum, F. equiseti, F. sporotrichioides, F. crookwellense, F. oxysporum, F. sambucinum var. coeruleum.     

The occurrence of Fusarium varieties and their mycotoxins in silo corn. 3. The effect of silaging on the zearalenone content of CCM corn

The influence of silaging on zearalenone already formed and on the growth of Fusarium culmorum in naturally contaminated CCM maize was studied. The zearalenone content remained approximately constant (13.35 +/- 2.94 mg/kg, n = 59) over the whole test period (12 weeks), whereas Fusarium culmorum could not longer be detected after 11 days. Thus the hypothesis that zearalenone survives the silaging process unchanged is experimentally strongly supported. The study confirms the view that zearalenone detected in maize silages is probably already formed in the field or during intermediate storing. Relations between the fermentation process and the toxin content of the silage could not be ascertained.     

Effects of graded levels of Fusarium toxin contaminated maize in diets for female weaned piglets.

A dose response study was carried out with piglets to examine the effects of increasing amounts of Fusarium toxins in the diet on performance, clinical serum characteristics, organ weights and residues of zearalenone (ZON) and deoxynivalenol (DON) and their metabolites in body fluids and tissues. For this purpose, Fusarium toxin contaminated maize (1.2 mg ZON and 8.6 mg DON per kg maize) was incorporated into a maize based diet for piglets at 0, 6, 12.5, 25 and 50% at the expense of control maize. The experimental diets were tested on 100 female piglets allotted to 20 boxes (five animals per box) covering a body weight range of 12.4 +/- 2.2 kg to 32.5 +/- 5.6 kg. Voluntary feed intake and, consequently, body weight gain of the animals receiving the highest proportion of Fusarium toxin contaminated maize were significantly decreased while the feed conversion ratio was not affected by the treatment. The mean weight of the uterus related to the body weight of the animals of the same group was increased by almost 100% as compared to the control. For this group, significantly decreased values of total serum protein were determined, while the serum activity of the liver enzyme glutamate dehydrogenase and the serum concentration of the follicle stimulating hormone were decreased for all treatment groups receiving 6% contaminated maize or more in the diet. Serum concentrations of immuneglobulins were not consistently altered by the treatment. Corresponding to the dietary exposure, increasing concentrations of ZON and alpha-zearalenol were detected in the bile fluid, liver and in pooled urine samples. The metabolite beta-zearalenol was detected only in bile fluid. The total concentration of ZON plus its metabolites in bile fluid correlated well with the diet contamination (r = 0.844). DON was found in serum, bile fluid and pooled urine samples while de-epoxy-DON was detected only in urine. The serum concentration of DON correlated well with the respective toxin intake 3-4 h prior to slaughtering (r = 0.957). For all mentioned analyses of residues it has to be noted that toxin residues were detectable even if negligible concentrations were present in the diet.     

The efficacy of a modified aluminosilicate as a detoxifying agent in Fusarium toxin contaminated maize containing diets for piglets

Two feeding experiments with female weaned piglets were carried out applying a complete two by two factorial design to investigate the effects of the dietary inclusion of 500 g/kg Fusarium toxin contaminated maize (8.6 mg/kg deoxynivalenol (DON); 1.2 mg/kg zearalenone (ZON)) and of 4 g/kg aluminosilicate (AS) as a detoxifying agent. The resulting four diets were fed ad libitum to a total of 80 piglets (20 piglets per group, allotted to a total of 20 pens) covering a live weight range of 10.5 +/- 1.3 to 27.5 +/- 4.4 kg in experiment 1, and to a total of 48 piglets (12 piglets per group, allotted to 12 pens) covering a live weight range of 9.7 +/- 1.8 to 21.4 +/- 4.8 kg in experiment 2. The animals of experiment 1 were slaughtered on days 34-36 of feeding the experimental diets. The mycotoxin analyses revealed that the control maize also contained considerable concentrations of Fusarium toxins, but the differences in DON and ZON concentrations between control and contaminated diets were sufficiently high to demonstrate both dose-related toxin effects. Voluntary feed intake and live weight gain of the animals were significantly reduced by the inclusion of Fusarium toxin contaminated maize into the diets in both experiments, while a significantly decreased feed to gain ratio was found in experiment 1. Furthermore, the relative weight of the uterus, stomach and heart of the animals fed the contaminated maize containing diets were significantly increased. Serum albumin concentrations and the activity of GLDH were significantly reduced by the inclusion of the contaminated maize. The addition of AS to the Fusarium toxin contaminated diets did not prevent or alleviate any of the mentioned effects. Moreover, the feed intake tended to be decreased by this supplementation in both experiments, while a significantly decreased feed to gain ratio was indicated for this factor in experiment one as well. The serum concentration of albumin and the activities of ASAT and gammaGT were significantly increased if AS was present in the diets while serum concentration of cholesterol and alpha-tocopherol were decreased significantly or in tendency, respectively. The concentrations of retinol and retinyl esters in liver and serum were not altered by the treatments. The analysed concentrations of zearalenone (ZON) and its metabolites in the bile fluid clearly indicated the differences in dietary ZON concentrations and showed that AS was ineffective in preventing the absorption of the toxin from the gastrointestinal tract. Also, serum concentrations of DON reflected the DON intake prior to sampling. However, there were no differences between groups fed diets with or without AS which also suggests the inefficacy of the tested AS in preventing the DON absorption. The present investigations failed to demonstrate a detoxifying capacity of the tested additive and emphasize the general necessity for a critical verification of detoxifying agents in vivo.     

The occurrence of Fusarium strains and their mycotoxins in corn silage. 4. The occurrence of zearalenone in the first cut zone of horizontal silos

Studies of the occurrence of zearalenone in the cutting surface of a horizontal silo were carried out over 12 days. On all sampling days the silage contained less than 0.1 mg/kg zearalenone (detection limit of the thin-layer chromatographic procedure). Zearalenone could not be detected in silage put into interim store over a period of 17 days either. The results document that zearalenone-producing Fusarium species have no considerable share in the decay of maize silage.     

The occurrence of Fusarium varieties and their mycotoxins on silo corn. 1. A method for the determination of zearalenone in corn and corn silage by high performance liquid chromatography (HPLC) with fluorescence detection

A method for the determination of zearalenone in maize and maize silage was developed which distinguishes itself by the effective and fast cleaning of the extracts with the help of a silica gel minicolumn. The samples were extracted with chloroform/methanol (9 + 1) and cleaned on a silica gel minicolumn after acid-base partition. The zearalenone was quantitatively determined optionally by means of high-performance liquid chromatography (HPLC) with fluorescence detection (excitation wavelength 236 nm, emission filter 418 nm) or thin-layer chromatography (TLC), p-methoxybenzene diazonium fluoroborate and aluminium chloride were used as detection chemicals. The limits of detection are 0.01 mg/kg (HPLC) and 0.1 mg/kg resp. (TLC), the average recovery is 81%. The method was used for the determination of zearalenone in grain maize, CCM silage and silage from whole maize plants.     

Effects of level of feed intake and Fusarium toxin-contaminated wheat on rumen fermentation as well as on blood and milk parameters in cows

The aims of this study were to examine the effects of and possible interactions between dry matter (DM) intake and feeding Fusarium toxin-contaminated wheat on ruminal fermentation, serum chemical parameters and milk yield of dairy cows. Fourteen dairy cows equipped with ruminal and duodenal cannulas were analysed. All animals were fed the same ration, the daily feed amounts being adjusted to current performance. On DM basis, the ration consisted of 60% concentrate including 55% wheat [Fusarium-contaminated wheat (mycotoxin period) or control wheat (control period)] and was completed with 40% maize and grass silage. Each cow was fed the contaminated wheat [deoxynivalenol (DON), 8.21 mg/kg DM and zearalenone (ZON), 0.09 mg/kg DM] and the control wheat (0.25 mg DON/kg DM and 51 microg ZON/kg DM). As expected, a higher organic matter (OM) intake decreased the amounts of fermented crude nutrients related to the respective intakes. An increased amount of crude protein degraded (p < 0.05) and a lower molar percentage of propionate in the rumen fluid were observed when feeding the Fusarium toxin-contaminated wheat at increased OM intakes in comparison with the control wheat. The activities of serum aspartate aminotransferase (ASAT; p < 0.001), glutamate dehydrogenase (GLDH; p < 0.01) and gamma glutamyl transferase (gamma-GT; p < 0.01) increased with increasing OM intake and were not related to the mycotoxin contamination of the wheat.     

镰刀菌毒素对断奶仔猪血清酶、肝脏抗氧化功能及组织病理学的影响

试验旨在研究镰刀菌毒素污染日粮对断奶仔猪血清酶、肝脏抗氧化功能及组织病理学的影响。选择35日龄体重为(8.45±0.94) kg的健康三元杂交(杜×长×大)断奶雌性仔猪40头,随机分为2组,每组20个重复,每个重复1头猪。对照组饲喂基础日粮,试验组饲喂用霉变玉米和霉变玉米蛋白粉替代基础日粮中50%的玉米和玉米蛋白粉配制而成的镰刀菌毒素污染日粮(玉米赤霉烯酮(ZEN) 0.90 mg/kg,呕吐毒素(DON) 1.43 mg/kg,烟曲霉毒素(FUM) 5.85 mg/kg)。仔猪单栏饲喂,预试期7 d,正试期35 d。结果表明:①与对照组相比,试验组断奶仔猪血清中谷草转氨酶(AST)、谷丙转氨酶(ALT)和碱性磷酸酶(ALP)活性均显著升高(P<0.05),肝脏相对重显著降低(P<0.05);②与对照组相比,试验组断奶仔猪血清和肝脏中谷胱甘肽过氧化物酶(GSH-Px)和总超氧化物歧化酶(T-SOD)活性均显著降低(P<0.05),而丙二醛(MDA)含量显著升高(P<0.05);③病理组织学观察发现,试验组断奶仔猪肝脏出现一定程度的组织损伤,部分肝小叶边缘发生明显的炎性细胞浸润,肝细胞发生局部空泡变性。由此可知,镰刀菌毒素污染日粮(0.90 mg/kg ZEN,1.43 mg/kg DON,5.85 mg/kg FUM)饲喂断奶仔猪可引起仔猪血清酶活性改变,肝脏抗氧化功能降低,肝脏组织出现一定程度的病理损伤,从而影响肝脏功能的发挥。     

Effects of Fusarium Toxins on Serum Enzymes Activity,Liver Antioxidant Function and Histopathology of Weaned Gilts

The objective of the present study was to investigate the effects of Fusarium toxins contaminated diet on serum enzymes, liver antioxidant function and histopathology of weaned gilts.Forty healthy weaned gilts (Duroc×Landrace×Yorkshire) aged 35 d with body weight of (8.45±0.94) kg were randomly allocated into 2 groups with 20 replicates per group and 1 pigs per replicate.Gilts in the control group were fed with basal diet, and those in the experiment group were fed with Fusarium toxins contaminated diet made by replacing 50% of corn and corn gluten meal in the basal diet with the naturally contaminated corn and corn gluten meal (0.90 mg/kg ZEN, 1.43 mg/kg DON, 5.85 mg/kg FUM).Gilts were fed individually in a metabolic cage for 35 d after 7 d adaptation.The results showed as follows:① Compared with control group, the serum activities of AST, ALT and ALP in experimental group were significantly increased (P<0.05), and the liver index of experiment group was significantly decreased (P<0.05).②Compared with control group, the activities of GSH-Px and T-SOD in serum and liver of experimental group were significantly decreased (P<0.05), and the MDA content in serum and liver were significantly increased (P<0.05).③ Histological examination of liver in experiment group revealed a certain degree of damage, with obvious inflammatory cell infiltration partly at the margin of hepatic lobule and vacuoles degeneration of local hepatic cells.The results indicated that Fusarium toxins contaminated diets (0.90 mg/kg ZEN, 1.43 mg/kg DON, 5.85 mg/kg FUM) could change serum enzymes activity and impair liver antioxidant function, with a certain degree of pathological injury of liver in the present study, which had a negative impact on the normal liver function in weaned gilts.     

Absorption, metabolism and excretion of 3-acetyl DON in pigs.

The absorption, metabolism and excretion of 3-acetyldeoxynivalenol (3-aDON) in pigs were studied. Pigs with a faecal microflora known to be able to de-epoxidate trichothecenes were used in the experiment. The pigs were fed a commercial diet with 3-aDON added in a concentration of 2.5 mg/kg feed for 2.5 days. No traces of 3-aDON or its de-epoxide metabolite were found in plasma, urine or faeces. Deoxynivalenol (DON) was detected in plasma as soon as 20 min after start of the feeding. The maximum concentration of DON in plasma was reached after 3 h and decreased rapidly thereafter. Only low concentrations close to the detection limit were found in plasma 8 h after start of the feeding. A significant part of the DON in plasma was in a glucuronide-conjugated form (42 +/- 7%). No accumulation of DON occurred in plasma during the 60 h of exposure. The excretion of DON was mainly in urine (45 +/- 26% of the toxin ingested by the pigs) and only low amounts of metabolites of 3-aDON (2 +/- 0.4%) were recovered in faeces. De-epoxide DON constituted 52 +/- 15% of the total amount of 3-aDON-metabolites detected in faeces. The remaining part in faeces was DON. DON was still present in the urine and faeces at the end of the sampling period 48 h after the last exposure. The results show that no de-epoxides are found in plasma or urine in pigs after trichothecene exposure, even in pigs having a faecal microflora with a de-epoxidation activity. The acetylated form of the toxin is deacetylated in vivo. Furthermore, the experiment shows that the main part of DON is rapidly excreted and does not accumulate in plasma, but a minor part of the toxin is retained and slowly excreted from the pigs.     

Effects of Fusarium toxin-contaminated wheat grain on nutrient turnover, microbial protein synthesis and metabolism of deoxynivalenol and zearalenone in the rumen of dairy cows

The aim of the present study was to examine the effects of feeding Fusarium toxin-contaminated wheat to dairy cows on nutrient utilization in the rumen and on duodenal flow of deoxynivalenol (DON), zearalenone (ZON) and their metabolites. Six dairy cows fitted with a large rumen cannula and a simple T-shaped cannula at the proximal duodenum was used in two experiments. The experiments included a control period in which the uncontaminated control wheat was fed and a period in which the control wheat was replaced by the Fusarium toxin-contaminated wheat (8.05 and 7.15 mg DON/kg and 0.26 and 0.1 mg ZON/kg in Expts 1 and 2 respectively). The wheat portion of the daily ration amounted to 50% on a dry matter (DM) basis and rations were completed with hay or grass silage. Five of the six cows were non-lactating and the total daily DM-intake ranged between 4 and 12 kg. The pH-values and the concentration of volatile fatty acids in ruminal fluid were not significantly influenced by feeding the contaminated wheat. In contrast, the postprandial ammonia concentration was consistently higher when the mycotoxin-contaminated wheat was fed. Moreover, the flow of microbial protein and utilizable protein at the duodenum were reduced at the same time. The concentrations of DON and ZON and of their metabolites in freeze-dried duodenal digesta were either not detectable or negligible during the control periods whereas distinct concentrations were measured during the periods where the contaminated wheat was fed. DON was nearly completely metabolized to de-epoxy-DON and the flow at the duodenum ranged between 4% and 28% of DON-intake. The ZON metabolites alpha-zearalenol (ZOL) and beta-ZOL were recovered at the duodenum beside the parent toxin ZON. Their recovery as a percentage of ZON-intake ranged between 43% and 132%. In conclusion, feeding of Fusarium toxin-contaminated wheat altered the ruminal protein utilization. The question of whether this effect was a result of the mycotoxin being present in the rumen or of Fusarium growth-related structural (cell wall) changes of the wheat grain needs to be clarified. The low recovery of DON at the duodenum would indicate either a nearly complete degradation of the molecule in the rumen or an absorption by the mucosa of the rumen, whereas the higher ZON recovery would suggest a lower degradation of the parent toxin in the rumen and/or recovery of some bile-originating entero-hepatic cycling ZON/metabolites.     

Effects of Fusarium toxin contaminated wheat and of a detoxifying agent on performance of growing bulls, on nutrient digestibility in wethers and on the carry over of zearalenone.

Experiments were carried out to examine the effects of a Fusarium contaminated wheat (10 mg deoxynivalenol and 0.76 mg zearalenone, ZON, per kg dry matter) and of a detoxifying agent (Mycofix Plus, Biomin GmbH, Herzogenburg, Austria) on the growing performance of bulls, carry-over of ZON and its metabolites into body fluids and tissues, and on nutrient digestibility in wethers. The experiments were designed according to a complete two by two factorial approach which meant that both the uncontaminated control wheat and the Fusarium toxin contaminated wheat were tested both in the absence and presence of Mycofix Plus. The growing experiment with bulls (n = 14 per treatment) covered the live weight range between 244 kg and 460 kg. The respective wheat batches were included in the concentrate portion at 65%. Concentrates were fed according to plan whereas maize silage was offered for ad libitum consumption. Daily dry matter intake and live weight gain [kg per animal and day] were 7.40, 7.52, 7.51 and 7.49 and 1.367, 1.296, 1.380 and 1.307 for bulls fed the unsupplemented control wheat, the supplemented control wheat, the unsupplemented and Fusarium toxin contaminated wheat and the supplemented Fusarium toxin contaminated wheat, respectively. ZON and its metabolites were not detected in edible tissues. The most striking effects of feeding the Fusarium toxin contaminated wheat on carcass characteristics were a reduced dressing percentage, an increased weight of the emptied gastro-intestinal tract and a reduced weight of the testicles. No effect of the detoxifying agent was seen for these parameters whereas heart weight increased independently of Fusarium toxin contamination of the concentrates. Nutrient digestibility of the two wheat batches, unsupplemented or supplemented with Mycofix Plus was evaluated according to the difference method using wethers. Presence of Fusarium toxins in wheat did not influence its feeding value. The effects of the addition of the detoxifying agent were mycotoxin unspecific and resulted in an increase in apparent digestibility of crude protein and a decrease in crude fiber digestibility. It is concluded that feeding of Fusarium toxin contaminated wheat did not adversely affect performance of growing bulls (approximately 2.2 mg DON and 0.1 mg ZON per kg complete ration at a reference dry matter content of 88%) or nutrient digestibility in wethers. The effects of the detoxifying agent Mycofix Plus on growing performance and on nutrient digestibility were rather Fusarium toxin unspecific. The slightly negative effects on growing performance needs to be examined further.     

Fusarium crookwellense-produced zearalenone in maize stubble in the field

Waste grain and vegetative material (stems and leaves) collected from a maize field several months after harvest was analysed by bi-dimensional thin layer chromatography for the presence of aflatoxins, deoxynivalenol, ochratoxin A, sterigmatocystin, T-2 toxin and zearalenone. Deoxinivalenol (0.7 mg/kg) and T-2 toxin (4.1 mg/kg) were found in the grain and zearalenone (3.0 mg/ kg) was found in the stem and leaf. No other toxins were detected. The stubble was examined for the presence of potentially toxigenic Fusarium species, and F. poae, F. moniliforme var. subglutinans and F. crookwellense were isolated and identified. When these isolates were cultured on cracked corn, only F. crookwellense was found to produce micotoxins and then only zearalenone was detected. As corn stubble is commonly grazed in Argentina and in other countries, these findings identify a further source of mycotoxins that may adversely affect animal health and productivity.     

Subacute effects of moderate feed loads of isolated Fusarium toxin deoxynivalenol on selected parameters of metabolism in weaned growing piglets

In 36 female weaned piglets, the effect of different dosages (0, 300, 600 and 1200 microg/kg feed) of isolated, pure Fusarium toxin deoxynivalenol (DON) was examined during a period of 8 weeks. Standardised trial conditions were provided. Pigs were fed restrictively to allow a complete feed intake of all animals. Parameters of liver integrity, haematological data and blood concentrations of some selected metabolic components of energy and protein metabolism were examined weekly. Enzyme aspartate aminotransferase was affected subclinically by age and significantly by dosage, which was proved by Wald F-test. Some additional enzymes, for instance alanine aminotransferase, gamma glutamyl transferase, glutamate dehydrogenase and sorbit dehydrogenase, showed no clear systematic effect. Urea and glucose in the blood were inter-related. Depending on DON load with increasing glucose concentrations, the urea level declined. Albumin and total protein in serum showed no significant DON-related effect. Haemoglobin in blood was found to be significantly affected by DON, which was proved by the Wald F-test, where the effect was more pronounced with 600 microg DON/kg diet compared to 1 200 microg DON/kg. An obvious DON-related affection of liver, N-metabolism and stimulation of haematopoiesis depending on dosage and time is discussed.     

Natural deoxynivalenol (DON) contamination of wheat samples grown in 1998 as determined by high-performance liquid chromatography

A high-performance liquid chromatography--diode array detection (HPLC-DAD) method was developed for determining the deoxynivalenol (DON) content of wheat and other cereals. The samples were extracted with a mixture of acetonitrile and water (84 + 16). Part of the extract was evaporated and purified on Florisil and activated charcoal columns. HPLC separation was performed on a C18 column, using acetonitrile-water (8 + 92) as eluent. Diode array detection (DAD) was performed at 218 and 236 nm, by determination of the UV spectrum. Quantitative analysis was carried out by the external standard method, using the UV spectrum obtained by DAD for confirmation. The recovery rate of DON was 75 +/- 3.1% and the detection limit was 0.05 mg/kg DON. Using this method, the DON content of 99 feeding wheat samples grown in the northeastern part of Hungary in 1998 was determined. Eighty-eight percent of the samples originating from three counties contained 0.94 mg/kg DON on the average. The highest individual value was 4.3 mg/kg. DON contamination of wheat was of higher prevalence (100%) and severity (0.27-4.3 mg/kg) in the southeastern county of Békés than in Szabolcs county located in the northeastern part of Hungary (ratio of positive samples: 82%; DON concentration: 0.05-1.3 mg/kg). The higher than usual DON contamination of feeding wheat can be explained by the rainy summer weather. DON contamination of feeding wheat poses a major risk to the production and animal health status of pig herds.     

Occurrence of Fusarium strains and their mycotoxins on corn silage. 6. Formation of zearalenone and trichothecenes (type A) by indigenous Fusarium isolates

A total of 399 indigenous Fusarium strains mainly isolated from silage maize were tested for the production of zearalenone and type A trichothecenes by thin-layer chromatography and biological assays. About 45% of the isolates examined were capable of producing different levels of zearalenone and trichothecene toxins on a cracked corn substrate. The majority of these strains (75%) produced zearalenone only and no trichothecenes type A. The results of the biological tests indicated a higher rate of toxin-positive extracts than chemical analysis. Isolates of nine out of seventeen Fusarium species examined produced one or several mycotoxins looked for. The most important toxin producers were F. culmorum and F. crookwellense (zearalenone) and F. sporotrichioides (trichothecenes type A), respectively. F. avenaceum, the species most frequently isolated from silage maize, produced neither zearalenone nor trichothecenes but avenacein Y a antibiotic compound. First results of a study of the production of type B trichothecenes have shown that indigenous F. culmorum isolates were capable of producing high levels of deoxynivalenol.     

Effects of Fusarium toxins on growth, humoral immune response and internal organs in weaner pigs, and the efficacy of apple pomace as an antidote

A feeding trial using 220 weaner pigs which comprised two experimental series was conducted to investigate the effects of diets contaminated with the Fusarium toxins deoxynivalenol (DON) and zearalenone (ZON) and to test the hypothesis that apple pomace acts as an antidote to these mycotoxins. Two diets without contaminated wheat, containing either no pomace or 8% pomace, and two diets with naturally contaminated wheat (3.2 mg DON and 0.06 mg ZON, and 2.1 mg DON and 0.25 mg ZON per kg diet in series 1 and 2 respectively), containing either no pomace or 8% pomace were fed ad libitum for 5 weeks. Mycotoxin exposure lowered feed intake (p < 0.01) and growth (p = 0.05), and tended to decrease the energy conversion ratio (p = 0.06). Although the intake of apple pomace did not increase feed intake, it increased the growth rate (p = 0.04), mainly by restoring growth in the presence of mycotoxins (p = 0.08 for the interaction mycotoxin x pomace). In the first experimental series, the animals were immunized with a parvovirus vaccine. The percentage of seroconverting animals did not differ between the treatments (p = 0.56), which indicates that DON did not affect the humoral immune response. In the second experimental series, female piglets fed the contaminated diets had heavier uteri than piglets fed the uncontaminated diets (p < 0.01), regardless of pomace supplementation. The results show that pomace may alleviate the negative effect of DON on growth but does not counteract the hormonal effects of ZON.     

The occurrence of Fusarium varieties and their mycotoxins in silo corn. 2. The formation of zearalenone in the field by artificial infection of silo corn with Fusarium culmorum (W. G. Smith) Sacc

The formation of zearalenone in a maize plot artificially infected with Fusarium culmorum was studied. The zearalenone concentration steeply increased only in the 8th week after inoculation and reached a maximum value of ca. 7 ppm, whereas zearalenone could not be detected in the control variants. The crude nutrient and dry matter content was not significantly influenced by the fungal infection. The infected crop showed average ear dry weights distinctly lower than that of the control variants (P less than or equal to 0.001). Apart from zearalenone, the mycotoxin deoxynivalenol was qualitatively detected in the infected maize. The toxicological relevance of the ascertained zearalenone content with regard to the health of dairy cattle and pigs was discussed.     

On the effects of a chronic deoxynivalenol intoxication on performance, haematological and serum parameters of pigs when diets are offered either for ad libitum consumption or fed restrictively

Wheat infected naturally with Fusarium, contaminated mainly with deoxynivalenol (DON) (16.6 mg DON/kg), was added to a total constant wheat content of 400 g/kg diet. To distinguish between differences in feed intake and specific effects of the DON contaminated diet, control and DON contaminated feed was administered for 11 weeks under ad libitum and restrictive feeding conditions to 48 pigs of both sexes, which were randomly divided into four groups (n = 12 per group). Feed intake was 2.90 kg/day, live weight gain 987 g/day and feed to gain ratio 2.77 kg/kg for the ad libitum fed control group. The group fed DON contaminated wheat ad libitum significantly consumed 15% less feed and gained 13% less live weight, while the feed to gain ratio was unaffected. Moreover, it was concluded that the lower growth performance by DON contaminated feed resulted mainly from the lower voluntary feed intake, because there were no differences in live weight gain between the groups with the restrictive feeding regimen. On the contrary, metabolizable energy, nitrogen retention digestibility of organic matter, crude protein, crude fat and crude fibre were significantly increased by 3, 10, 3, 6, 9 and 20% in the DON group respectively. Animals fed DON contaminated diets needed more time to consume the restrictive ration than the control group. For example in the first hour after feeding 85% of the control pigs had consumed all feed, but only 39% of the DON group had. There were only few differences in haematological and serum parameters, which were characterized by a high variation between individuals. DON and IgA concentrations in serum were significantly influenced by DON exposure.     

Diagnostic opportunities for evaluation of the exposure of dairy cows to the mycotoxins deoxynivalenol (DON) and zearalenone (ZEN): reliability of blood plasma,bile and follicular fluid as indicators

To investigate the usefulness of follicular fluid (FF) in relation to blood plasma and bile as indicators of exposure of dairy cows to ZEN, DON and their metabolites, a dose–response study was performed with 30 dairy cows. The cows, 10 in each group (named CON; FUS‐50, FUS‐100), received a diet with three different concentrations of Fusarium toxin‐contaminated maize. Thereby, the following dietary concentration were reached: CON (0.02 mg ZEN and 0.07 mg DON, per kg dry matter, DM), FUS‐50 (0.33 mg ZEN and 2.62 mg DON, per kg DM) and FUS‐100 (0.66 mg ZEN and 5.24 mg DON, per kg DM). ZEN, DON and de‐epoxy‐DON (de‐DON) were detected in FF. Based on the linear regression between toxin concentration in plasma and FF, it seems that about 50 % (m = 0.5) of ZEN present in plasma is present in FF while an increase of 1 ng/ml DON or de‐DON in plasma is paralleled by an increase of 1.5 ng/ml DON or 1.1 ng/ml de‐DON in FF. ZEN, DON and their metabolites, except zearalenone (ZAN), were also detected in bile. Contrary to DON and de‐DON, ZEN and its metabolites were accumulated in bile so that the concentration of ZEN and metabolites was much higher than for DON and de‐DON. The main compound was β‐zearalenol (β‐ZEL). The biliary ZEN, α‐zearalenol (α‐ZEL) and β‐ZEL concentration correlated linearly with each other with an uncertainty of <15 % (r² ≥ 0.86), whereas the ratio between ZEN: α‐ZEL: β‐ZEL was about 1.5:1:11. With the help of established linear relationship between toxin intake and toxin concentration, bile could be used as diagnostic indicator to assess the exposure of cows.