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.     

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.     

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.     

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.     

The occurrence of Fusarium toxins in feed

Fusariotoxins can be found in imported feed as well as in crops from the Middle-Europe-Region. Concerning frequency of contamination, zearalenone is most important in the Federal Republic of Germany. From the grains, maize and oats are mainly affected. Frequency and intensity of contamination however, variates, depending on several factors as climate or genetical resistance. Typical districts with high frequency of contamination cannot be found in the FRG at the present status of knowledge. Feed-intoxications by zearalenone predominantly can be seen in pigs, cases with ruminants, horses or fowl rarely can be found. As imported feeds--especially those of the by-products of the wet-milling technique of maize--can be contaminated with zearalenone, a consequent control is demanded. Additionally culture techniques, genetical selection, seed treatment and harvesting should be optimized. A scientific-based tolerable limit till now cannot be stated. There are however some hints, that female pigs show cystic degenerations of the ovary receiving 50 microgram per kg diet. Naturally contaminated feed with 100 microgram fed for several weeks to growing female pigs induced signs of hyperestrogenism. Trichothecene contamination was found with lower frequency in the Federal Republic especially with DON, which dominates in Austria and some districts of the USA. From the contaminated feeds, maize and oats should be mentioned with priority. Ensiled products of the maize plant show some degradation during the ensiling process. Husks contain higher levels than the endosperm. No differences between conventionally and alternatively (biologic dynamic) grown crops could be found. A value for a tolerable daily intake cannot be stated at the present status of knowledge.(ABSTRACT TRUNCATED AT 250 WORDS)     

Occurrence of Fusarium strains and their mycotoxins in corn silage. 7. Formation of deoxynivalenol (DON) in a silage corn plot artificially inoculated with Fusarium culmorum and the effect of silaging on the stability of the DON formed

The formation of deoxynivalenol in a maize plot inoculated with Fusarium culmorum was studied over a growing season. Already three weeks after inoculation 4.9 mg/kg of DON were measured in the infected ears. The toxin concentration increased continuously up to harvest after eight weeks to a value of 261 mg/kg. Ensilage experiments in laboratory scale silos have shown that the DON content of naturally contaminated corn-cob-mix was not reduced during the ensilage process. It was concluded that infection of maize plants by toxin-producing Fusarium species followed by DON production in the field seems to be the most probable way of contamination of maize silage with this mycotoxin.     

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.     

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.     

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.     

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.     

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.     

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.     

超声波预处理对全株青贮玉米品质的影响

为研究超声波预处理对全株青贮玉米品质的影响,设置空白对照组、超声处理组(5、10、15、20、25 min)和乳酸菌对照组进行青贮玉米品质研究.结果表明:15 min和20 min超声处理后,全株玉米青贮饲料感官评定属于优良级.与对照组相比,超声处理后饲料的pH和氨氮比分别降低7.71％和7.82％,乳酸和乙酸含量分别...     

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.     

Effect of Fusarium roseum (Gibberella zea) on pregnancy and the estrous cycle in gilts fed molded corn on days 7-17 post-estrus

A laboratory produced corn culture of Fusarium roseum (Gibberella zea) was fed as 10% of the total diet to bred and non-bred gilts on days 7-17 postestrus. The corn culture contained both zearalenone and deoxynivalenol by analysis, and caused considerable feed refusal. Although 6 of 10 bred gilts fed the corn culture appeared to be pregnant by ultrasound testing between days 40-50 post-breeding, none of them farrowed. Progesterone analyses indicated that none of the 10 gilts cycled normally during the 20 week observation period. Three maintained high serum progesterone (greater than 10 ng/ml) during the entire period. Progesterone analyses were similar in 5 non-bred gilts fed the corn culture in that none of them cycled normally in 20 weeks. The retention or loss of corpora lutea could not be attributed to levels of luteinizing hormone, as no relationship was found between concentrations of progesterone and luteinizing hormone. This experiment indicates that limited dietary exposure of female swine to Fusarium roseum infected corn can result in embryonic loss and disruption of normal reproductive cycling for an extended length of time.     

Zearalenone intoxication of pigs

Mycotoxicosis due to ingestion of zearalenone was detected on 2 pig farms on the Atherton Tableland in northern Queensland. In one herd of 200 pigs, this resulted from feeding maize which had been stored with a high moisture content. In the other herd of 1400 pigs, it resulted from feeding sorghum grain which was rain affected before harvest. Concentrations of zearalenone in the feeds ranged up to 8 mg/kg. Most prepubertal gilts in the herds displayed enlarged teats and signs of oestrus such as having red, swollen vulvas. In several cases both rectal and vaginal prolapses occurred. On one of the farms, 25 pigs died as a direct result of prolapses. Autopsy of a 3-month-old gilt revealed apparently enlarged ovaries and uterine horns. Sows and boars seemed to be unaffected. Four gilts failed to conceive following mating during the period of zearalenone ingestion, but apart from this and the deaths from prolapses, production of the herds appeared to be unaffected.     

十个玉米品种在广州种植和青贮的潜力研究

为筛选适宜在广州种植的青贮玉米品种,采用随机区组设计种植和袋装青贮的方法,研究了10个玉米品种(京科青贮301、农大108、赣单2、大丰3、宜黄单4、雅玉8、先玉335、郑单958、雅玉26、华玉8)的种植和青贮潜力。结果表明,1)品种间全株干物质产量(P<0.05)和消化率(P<0.01)差异显著,参试品种均超过对照品种华玉8,其中雅玉8的干物质产量最大,达14.30 t/hm²;京科青贮301干物质消化率最高,达78.15%。品种间的相对饲用价值呈现显著差异(P<0.05),京科青贮301的相对饲用价值为123.52,比对照高17.90%(P<0.05),郑单958、赣单2、先玉335、雅玉8、农大108不同程度地高于对照。2)品种间的干物质、粗灰分和无氮浸出物含量差异显著(P<0.05),各品种干物质含量比对照均有不同程度的提高,雅玉26、大丰3、雅玉8干物质含量均达到40%;雅玉26、大丰3、农大108和雅玉8的无氮浸出物含量较高,分别达到65.31% DM、63.94% DM、63.38% DM和62.17% DM。品种间的粗蛋白、粗脂肪和粗纤维含量均无显著差异(P>0.05)。3)玉米品种间植株附着的乳酸菌和霉菌差异显著(P<0.05),郑单958的乳酸菌数达10⁶ cfu/g FM,高于其他品种。4)各玉米品种青贮后的pH值、乳酸和丙酸含量差异显著(P<0.05),对照华玉8的pH值最低为3.63,雅玉8的pH值最高,达4.22;对照华玉8的乳酸含量最高,达9.16% DM。丁酸含量差异不显著(P>0.05),但雅玉8和郑单958没有检测到。各品种青贮的NH₃-N/TN含量差异极显著(P<0.01),雅玉8、郑单958和大丰3分别为8.81%、10.04%和10.61%,至少比对照低13.39%。综合各品种全株干物质产量、营养价值和青贮效果,雅玉8在广州地区种植作青贮饲料利用更有潜力。     

Effect of Fusarium roseum corn culture containing zearalenone on early pregnancy in swine

A corn culture of Fusarium roseum was added to a standard corn-soybean swine gestation ration. Low, middle, and high dosage mixed feeds contained 7, 38, and 64 mg of zearalenone/kg of feed (7, 38, and 64 ppm) and 0.5, 2.5, and 4.5 mg of deoxynivalenol/kg, respectively. Control feed was the standard ration without added F roseum corn culture. Mature gilts were bred by natural service and fed control or F roseum molded feed from 3 to 34 days after breeding. The main effect of the molded feed was an inhibition of fetal development, with decreased numbers of fetuses present in treated animals at slaughter (38 to 43 days after breeding). Normal litters were present in 7 of 8 control animals, in 2 of 4 gilts given the low-dosage feed, in 1 of 4 gilts given the medium dosage, and in 0 of 4 given the high-dosage feed. Corpora lutea were maintained in all treated animals, as evidenced by serum progesterone concentrations. Serum estradiol concentrations were decreased in gilts in the middle- and high-dosage groups. The genital system of the gilts fed low- and middle-dosage feeds had a gross and microscopic appearance similar to that of the pregnant controls and reflected prolonged progesterone stimulation. Morphologic changes in the genital system of the high-dosage group were intermediate between changes induced by progesterone and those induced by estrogen. Clinical signs of hyperestrogenism and partial feed refusal were noticed in only some of the high-dosage group animals.     

Initial research on the use of mixed corn grain and stalk silage in broiler fattening

The suitability of a corn and cob maize silage (CCM) as a component rich in energy in the fattening ration was investigated in a growth experiment with male broilers. The CCM silage with a dry matter content of 60.2% contained the following substances determining its value (per 1 kg dry matter of the feed): 102 g crude protein, 61 g crude fibre and 682 energetic feed units for chickens (EFUc). CCM silage was either fed as a component of a feed mixture consisting of 70.5% CCM silage and 29.5% protein concentrate (all values of original substance) or both components of the ration were fed to broilers separately. The protein concentrate was composed as follows (values per kg): 650 g soybean oilmeal, 110 g fishmeal, 85 g tankage from rendering plants, 55 g torula yeast, 70 g mineral mixture and 30 g of a mixture of biologically active substances. The broilers of the control group received commercial fattening feed for broilers with coarse maize meal as cereal component. The feed mixture with CCM silage and separate CCM silage were accepted readily. When CCM silage and protein concentrate were offered alternatively, the same amount of CCM silage was consumed but 8% less protein concentrate. The broilers fed with CCM silage plus protein concentrate reached 96-97% of the live weight of the control animals (1.952 g/animal, 49th day), which received conventional feed, although their net energy intake was 10% lower. This proves a more favourable net energy expenditure for the test groups fed with CCM silage.     

Determination of zearalenone in grains using high pressure liquid chromatography

The determination of zearalenone content in cereals (maize, wheat and barley) was performed by means of liquid chromatography using the Czechoslovak-made apparatus. This method enables to determine this mycotoxin up to the concentration of 8 micrograms per 1 kg of grain with the accuracy exceeding +/- 9%.