Decomposition of the Fusarium graminearum toxin zearalenone in storage conditions

The studies illustrate the effects of preservatives - "Luprosil" (propionic acid) and "Gasol" (contains organic acids and some additional compounds) on the growth of Fusarium graminearum and the quality of zearalenone in contaminated grain. The laboratory conditions resembled, concerning the supply of oxygen, the circumstances in the surface layers of preserved grain mass. The mycelium growth of the fungus Fusarium graminearum was visually observed. Three successions of studies of grain cultures were carried out before addition of preservatives and after 3, 14 and 28 days of storage: 1) liquid-chromatographic examination indicating the amount of soluble zearalenone in oat-wheat culture 2) bioassay indicating the amount of insoluble zearalenone in grain (solid residue) 3) bioassay indicating the total amount of zearalenone (insoluble + soluble zearalenone) in oat-wheat-barley culture. The preservatives completely prevented the visible mycelium growth of Fusarium graminearum. Propionic acid ("Luprosil") had no reducing effect on the quantity of zearalenone. "Gasol", on the contrary, reduced the amount of the mycotoxin very clearly. The decrease in different successions of studies was after 3, 14 and 28 days from the commencement of storage as follows: 1) 60, 90 and 95% 2) 15, 17 and 90% 3) 70, 80 and 90%.     

The Fusarium toxins deoxynivalenol (DON) and zearalenone (ZON) in animal feeding

The contamination of cereal grains with toxic secondary metabolites of fungi, mycotoxins, is a permanent challenge in animal nutrition as health and performance of the animals may be compromised as well as the quality of animal derived food. Therefore the present article reviews the issue of mycotoxins in animal nutrition. As the Fusarium toxins deoxynivalenol (DON) and zearalenone (ZON) are of particular importance under the production conditions in central Europe and Germany, with respect to their frequent occurrence in toxicologically relevant concentrations, special emphasis is layed on those mycotoxins. The effects of DON and ZON on susceptible animals as well as management strategies to cope with the contamination of grain with those toxins are reviewed.     

Chlamydia as the cause of abortions in horses

Between 1982 and 1989 59 equine fetuses were investigated for chlamydiae using animal experiments and embryonated eggs. Chlamydiae were isolated from 16 fetuses (27.1%) originating from 8 studs. The macroscopical lesions of the fetal organs were characterized by extensive haemorrhages. The histological picture shows severe lesions of the blood vessels of different organs. In 6 studs in which chlamydiae had been isolated, blood sera of clinically healthy and pregnant mares were investigated for antibodies during 1989 and 1990. Antibody titres between 1:10++ and 1:40 were detected by using complement fixation test in sera of mares of 4 studs.     

脱氧雪腐镰刀菌烯醇、玉米赤霉烯酮及其联合染毒对小鼠肝脏功能及肝细胞凋亡的影响

为探讨脱氧雪腐镰刀菌烯醇(DON)、玉米赤霉烯酮(ZEA)及其联合染毒对小鼠肝脏功能和肝脏细胞凋亡的影响,成年雌性昆明小鼠360只,体质量(20±1)g,随机分为9组,腹腔单独或联合注射(每隔24 h注射1次,连续4次)不同浓度的镰刀菌素(DON 1.5,2.5 mg/kg;ZEA 20,30 mg/kg)。于感染后0,3,5,8,12 d测定小鼠肝脏AST、ALT的活性和TP、ALB的含量;3,5,8 d测定肝细胞凋亡率的变化。结果表明,DON、ZEA单独或联合染毒均显著提高小鼠肝脏AST、ALT活性及肝细胞凋亡率(P0.01或P0.05),显著降低TP、ALB含量(P0.05);联合染毒组与相应单一染毒组相比差异显著(P0.01或P0.05),呈现明显的剂量-效应关系。联合染毒具有亚加性效应,以2.5mg/kg DON与30 mg/kg ZEA联合染毒所呈现的亚加性效应更明显。     

Secondary indigestion as a cause of functional pyloric stenosis in the cow

In 23 cows suffering from a secondary indigestion, in most cases with septicaemia, the syndrome of functional pyloric stenosis or vagal indigestion developed. The signs were anorexia, ruminal distension with fluid material, abomasal reflux into the ruminoreticulum, dehydration, hypochloraemic, hypokalaemic metabolic alkalosis and uraemia. These signs often disappeared after treatment of both the primary causative disease and the secondary indigestion. The importance of recognising this condition is emphasised, because the serious signs of the secondary indigestion may dominate the causative disease. The prognosis depends upon the causative disease and is not necessarily bad.     

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.     

Hypokalaemia as a cause of recumbency in an adult dairy cow

A 3-year-old Holstein cow was presented for evaluation of recumbency. Physical examination and laboratory evaluations resulted in a diagnosis of hypokalaemia causing extreme skeletal muscle weakness. Treatment involved intravenous and oral potassium supplementation, antimicrobial and anti-inflammatory therapy, and management of recumbency using a flotation tank (the Aquacow Rise System). The cow recovered and returned to the milking herd. Multifactorial elements were identified as the cause of hypokalaemia including inappetance, treatments for ketosis and administration of dexamethasone.     

The effects of "Gasol" grain preservative dosages on the growth of Fusarium graminearum and the quantity of the toxin zearalenone

In earlier experiments regarding the effects of preservative "Gasol" (containing various acids and additional compounds and intended for whole grain preservations) in recommended dosages, prevents the growth of Fusarium graminearum and reduces the amount of zearalenone when added to milled grain. It was proved in the tests carried out that the smaller dosages of "Gasol" were sufficient for the prevention of growth of the fungus and reduction in quantity of zearalenone. The degree to which the toxin was destroyed depended on the dosage of the preservation. A dosage twice as strong as that recommended in the instructions for practice destroyed all the toxin formed in the grain. A very small dosage of "Gasol" (1/8 of recommended dosage) prevented the growth of the fungus and only slightly reduced the amount of toxin only at the beginning of the test. Later, the growth of the fungus was more vigorous and significantly more toxin was present in the treated grain than in the grain which had never been treated with the preservatives, it has been proved that the preservative     

Failure to maintain luteal function: a possible cause of early embryonic loss in a cow.

The effect of early pregnancy failure on the release of prostaglandin F2 alpha (PGF2 alpha) in response to oxytocin (Ot) was examined in an abnormal breeder (AB) heifer that was not able to maintain a pregnancy beyond 21 days. This animal was used in three experiments: 1) She received one intravenous injection of 100 IU Ot 17 days after the onset of oestrus (Day 0). Frequent blood samples were taken for the measurement of 15-keto-13,14-dihydro-PGF2 alpha (PGFM) by radioimmunoassay. Daily samples for progesterone (P4) determinations were taken to monitor luteal function. This was then repeated using the same animal at either day 17 or 18 or 19 (day 17-19) of pregnancy. 2) Embryos from superovulated normal breeder (NB) donors were transferred at day 7 to the AB heifer as well as to NB control animals. 3) Seven day old embryos from the superovulated AB heifer were transferred to NB recipient animals. At day 17-19 of pregnancy all the recipient heifers (experiments 2 and 3) were subjected to the same protocol as in experiment 1. The results showed that the ability of Ot to stimulate PGF2 alpha release was reduced in the NB recipients bearing viable embryos when compared to cyclic animals. However, for the AB heifer, Ot stimulated PGF2 alpha release to the same extent whether the animal was cyclic or pregnant. Furthermore, the AB animal did not have the extended luteal function associated with removal of viable embryos on day 17-19. The data suggest that the embryonic loss might have been caused by failure of the embryos to prevent the luteolytic release of PGF2 alpha.     

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.     

Alopecia areata (pelade) in a cow

A case of alopecia areata (pelade) is described in a cow. Alopecia areata is a rare idiopathic dermatosis of cattle. It is characterized by asymptomatic, solitary or multiple, annular areas of noninflammatory alopecia. Scrapings and cultures are negative, and the diagnosis is confirmed by skin biopsies taken from early lesions, which reveal accumulations of lymphocytes around the bulbs of anagen hair follicles. There is no known effective and practical treatment for affected cattle. The dermatitis is a cosmetic problem, but does not seem to affect general health and production, and spontaneous remission may occur.     

The occurrence of a toxigenic strain of Fusarium tricinctum in connection with disease in a dairy cow]

The fungus Fusarium tricinctum, producing T-2 toxin, was isolated from mouldy maize silage. T-2 toxin was identified by TLC and by a bioassay. Consumption of mouldy silage resulted in a disease in a dairy cow, which had to be killed. The patho-anatomical findings obtained in the slaughtered cow generally suggested trichothecene poisoning. It was derived from these findings that the disease was due to the presence of trichothecenes in the feed.     

Datura contamination of hay as the suspected cause of an extensive outbreak of impaction colic in horses

Datura poisoning of horses is extensively reviewed. An outbreak of intractable impaction colic affecting 18 of 83 horses was stopped by withdrawing dried tef hay contaminated with young Datura plants. The dried, botanically identified Datura stramonium and D. ferox contained respectively 0.15% mass/mass (m/m) hyoscyamine as well as 0.16% m/m hyoscine (scopolamine) and only hyoscine at a concentration of 0.11% m/m. Immature, unidentifiable plants resembling D. stramonium, contained 0.14% m/m and 0.12% m/m of the 2 respective tropane alkaloids. The outbreak was characterised by protracted and repeated colic attacks due to impaction of the large colon and/or caecum without any other anti-muscarinic signs. Comparative analyses of single specimens of dried seed of the 2 species collected from both fertilised and waste areas revealed that young South African Datura spp. had levels of tropane alkaloids comparable to those in the well-known toxic seed and were, consequently, equally toxic. The inherent danger of tef hay being contaminated with Datura is emphasised. To our knowledge this is the 1st field case of poisoning in horses ascribed to the vegetative parts of Datura spp.     

Enteritis as a cause of mortality in the western bluebird (Sialia mexicana)

Increased mortalities in adult western bluebirds utilizing nestboxes were noted in western Oregon during 1998 and 1999. A necrohemorrhagic enteritis was found in 8 of 10 birds submitted for necropsy. Acanthocephalan parasites were present in four of eight birds with enteritis. Microscopic changes consistent with necrotic or ulcerative enteritis were commonly present. Anaerobic culture of the intestine yielded Clostridium perfringens in three of three birds. Genotype analysis of two of these isolates revealed them to be C. perfringens type A. Bacterial enteritis is believed to be the cause of the increased mortality rate, but further investigation is required to prove a definitive link to a clostridial agent.     

Orbital (retrobulbar) meningioma in a Simmental cow

A 12-year-old Simmental cow was presented with a moderately firm irregular whitish mass of approximately 5 cm in diameter, occupying the right orbit. Microscopically, a poorly differentiated neoplasm was observed. The immunohistochemical panel included cytokeratins, vimentin, epithelial membrane antigen, Factor VIII, CD34, Mart-1, Melan A, smooth muscle actin, desmin, chromogranin, neuron-specific enolase, S-100 protein, and MIB-1. The neoplasm was negative for all of them, with the exception of vimentin and S-100 protein. Transmission electron microscopy revealed abundant desmosomes. These findings support the diagnosis of orbital (retrobulbar) meningioma.     

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 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.