Thermostability of Fumonisin B1, a Mycotoxin from Fusarium moniliforme, in Corn

Fumonisin B₁ (FB₁) is a mycotoxin from Fusarium moniliforme that is frequently associated with corn. Thermal treatments are used in many processes concerning this cereal and its derivatives. The thermostability of this toxin in dry contaminated corn, resulting from F. moniliforme culture, was studied in different time-temperature combinations. FB₁ was quantified by instrumentalized thin-layer chromatography after a two-step sequential development and postchromatographic derivatization by p-anisaldehyde. The identity of FB₁ in extracts, before and after heat treatments, was confirmed by high-pressure liquid chromatography. For each temperature, the natural logarithm of the ratio of resulting FB₁ on initial content (In C/C₀) is linearly correlated to exposure time. The calculated half-lives (L₅₀), corresponding to the 50% value, were 10 min, 38 min, 175 min, and 8 h at 150, 125, 100, and 75°C, respectively. There is a linear relationship between calculated L₅₀s on a logarithmic scale and temperature. Therefore FB₁ is not significantly destroyed by the main drying processes of corn or thermal treatments used for its derivatives. Other associated means are required for detoxification.     

Production of fumonisins by Fusarium moniliforme and Fusarium proliferatum isolates associated with equine leukoencephalomalacia and a pulmonary edema syndrome in swine.

Fumonisin B1 (FB1) and FB2 were isolated from corn cultures of both Fusarium moniliforme and Fusarium proliferatum. Respective concentrations in culture materials of FB1 and FB2 ranged from 960 to 2,350 and 120 to 320 micrograms/g for F. moniliforme and from 1,670 to 2,790 and 150 to 320 micrograms/g for F. proliferatum. Thin-layer chromatography, gas chromatography-mass spectroscopy, high-performance liquid chromatography, and liquid secondary ion mass spectroscopy were used for detection. Fumonisins from F. proliferatum have not previously been reported.     

Production of fumonisins by Fusarium moniliforme and Fusarium proliferatum isolates associated with equine leukoencephalomalacia and a pulmonary edema syndrome in swine

Fumonisin B1 (FB1) and FB2 were isolated from corn cultures of both Fusarium moniliforme and Fusarium proliferatum. Respective concentrations in culture materials of FB1 and FB2 ranged from 960 to 2,350 and 120 to 320 micrograms/g for F. moniliforme and from 1,670 to 2,790 and 150 to 320 micrograms/g for F. proliferatum. Thin-layer chromatography, gas chromatography-mass spectroscopy, high-performance liquid chromatography, and liquid secondary ion mass spectroscopy were used for detection. Fumonisins from F. proliferatum have not previously been reported.     

Determination of benidipine in human plasma using liquid chromatography-tandem mass spectrometry

Fumonisins are water soluble mycotoxins produced by the fungus Fusarium verticillioides (formerly F. moniliforme). Fumonisin B(1) (FB(1)) is a diester of propane-1,2,3-tricarboxylic acid and 2-amino-12, 16-dimethyl-3,5,10,14,15-pentahydroxyeicosane, and is the most abundant of the naturally occurring fumonisins. Upon removal of the two tricarballylic acid side chains, the structure is referred to as hydrolyzed FB(1) (HFB(1)). FB(1) and HFB(1) are structurally similar to sphinganine, a sphingoid base. The fumonisins do not absorb UV light or fluoresce; therefore, derivatizing reagents are used for detection when separation is by high performance liquid chromatography (HPLC). The standard derivatizing reagent used for HPLC is ortho-phthalaldehyde (OPA) plus 2-mercaptoethanol (ME) reaction partner, however, the OPA-FB(1) derivative is not stable at room temperature. The objectives of this study were to: (1). determine the effect of temperature on the stability of the OPA-FB(1) derivative and (2). determine which structural characteristics of FB(1) contribute to the instability of the OPA-FB(1) derivative. The results indicate that OPA-FB(1), OPA-FB(3) and OPA-HFB(1) derivatives are unstable at 24 degrees C but that their stability improves significantly at 4 degrees C. The OPA-sphinganine derivative is stable for at least 24h at 24 degrees C. Thus, the instability of the OPA-FB(1) derivative may be attributed to its lack of a hydroxyl group at the carbon 1 position.     

Effects of temperature and incubation period on production of fumonisin B1 by Fusarium moniliforme.

The kinetics of the production of fumonisin B1 (FB1) by Fusarium moniliforme MRC 826 in corn cultures was investigated as a function of fungal growth at various incubation temperatures. The growth rate of F. moniliforme, as measured by ergosterol concentration, was higher at 25 degrees C than at 20 degrees C, reaching a stationary phase after 4 to 6 weeks in both cases. FB1 production commenced after 2 weeks during the active growth phase, continued to increase during the stationary phase, and decreased after 13 weeks. The overall maximal yield of FB1 (17.9 g/kg, dry weight) was obtained in corn cultures incubated at 20 degrees C for 13 weeks, but it was not significantly (P greater than 0.05) higher than the maximum yield (16.5 g/kg, dry weight) obtained at 25 degrees C after 11 weeks. However, a significantly (P less than 0.05) higher mean yield was detected at 25 degrees C (9.5 g/kg, dry weight) than at 20 degrees C (8.7 g/kg, dry weight). Production reached a plateau after 7 weeks of incubation at 25 degrees C or 9 weeks of incubation at 20 degrees C. The maximal production of FB1 at 30 degrees C was very low (0.6 g/kg, dry weight). FB1 was also found to be heat stable, as there was no reduction in the FB1 concentration after boiling culture material of F. moniliforme MRC 826.     

Production of [14C]fumonisin B1 by Fusarium moniliforme MRC 826 in corn cultures.

Kinetics of growth and fumonisin production by Fusarium moniliforme MRC 826 in corn "patty" cultures were investigated, and a technique was developed for the production of [14C]fumonisin B1 ([14C]FB1) by using L-[methyl-14C]methionine as the precursor. A significant (P < 0.01) correlation exists between fungal growth and FB1 (r = 0.89) and FB2 (r = 0.87) production in corn patties, beginning after 2 days and reaching the stationary phase after 14 days of incubation. [14C]FB1 was produced by adding L-[methyl-14C]methionine daily to cultures during the logarithmic phase of production. Incorporation of the isotope occurred at C-21 and C-22 of the fumonism molecule and was enhanced in the presence of unlabeled L-methionine. Although the concentration of exogenous unlabeled methionine is critical for incorporation of the 14C label, optimum incorporation was achieved by adding 50 mg of unlabeled L-methionine and 200 mu Ci of L-[methyl-14C]methionine to a corn patty (30 g) over a period of 9 days, yielding [14C]FB1 with a specific activity of 36 mu Ci/mmol.     

Effects of temperature and incubation period on production of fumonisin B1 by Fusarium moniliforme

The kinetics of the production of fumonisin B1 (FB1) by Fusarium moniliforme MRC 826 in corn cultures was investigated as a function of fungal growth at various incubation temperatures. The growth rate of F. moniliforme, as measured by ergosterol concentration, was higher at 25 degrees C than at 20 degrees C, reaching a stationary phase after 4 to 6 weeks in both cases. FB1 production commenced after 2 weeks during the active growth phase, continued to increase during the stationary phase, and decreased after 13 weeks. The overall maximal yield of FB1 (17.9 g/kg, dry weight) was obtained in corn cultures incubated at 20 degrees C for 13 weeks, but it was not significantly (P greater than 0.05) higher than the maximum yield (16.5 g/kg, dry weight) obtained at 25 degrees C after 11 weeks. However, a significantly (P less than 0.05) higher mean yield was detected at 25 degrees C (9.5 g/kg, dry weight) than at 20 degrees C (8.7 g/kg, dry weight). Production reached a plateau after 7 weeks of incubation at 25 degrees C or 9 weeks of incubation at 20 degrees C. The maximal production of FB1 at 30 degrees C was very low (0.6 g/kg, dry weight). FB1 was also found to be heat stable, as there was no reduction in the FB1 concentration after boiling culture material of F. moniliforme MRC 826.     

珍珠岩液体培养基制备镰刀菌素C的研究

串珠镰刀菌可利用羟基脯氨酸、蔗糖、甘油和珍珠岩(P)等组成的P液体培养基合成镰刀菌素c(Fc),其最高量为93 6mg/kg有机物,比在玉米渣培养基中形成的Fc量较高。用P液体培养基制备Fc,受蔗糖浓度、胺类和培养温度及培养时间等的影响。实验证明,由1g百姓遭基因氨酸、40g蔗糖和珍珠岩组或的P液体培养基．在28℃培养二周是形成Fc的理想条件。液体培养基中加八珍珠岩,Fc的形成量增加500多倍。     

Survey of fumonisin production by Fusarium species

Fumonisins B1 (FB1) and B2 (FB2), two structurally related mycotoxins with cancer-promoting activity, were recently isolated from corn cultures of Fusarium moniliforme MRC 826. These toxins have been reported to be produced also by isolates of F. proliferatum. Contamination of foods and feeds by F. moniliforme has been associated with human esophageal cancer risk, and FB1 has been shown to be the causative agent of the neurotoxic disease leukoencephalomalacia in horses. Because of the toxicological importance of the fumonisins, the potential to produce FB1 and FB2 was determined in a study of 40 toxic Fusarium isolates representing 27 taxa in 9 of the 12 sections of Fusarium, as well as two recently described species not yet classified into sections. With the exception of one isolate of F. nygamai, fumonisin production was restricted to isolates of F. moniliforme and F. proliferatum, in the section Liseola. The F. nygamai isolate produced 605 micrograms of FB1 g-1 and 530 micrograms of FB2 g-1, and the identity of the toxins was confirmed by capillary gas chromatography-mass spectrometry. This is the first report of the production of the fumonisins by F. nygamai.     

The mycotoxin fumonisin B1 transiently activates nuclear factor-κB, tumor necrosis factor α and caspase 3 via protein kinase Cα-dependent pathway in porcine renal epithelial cells

Fumonisin B1 (FB1) is a toxic mycotoxin produced by Fusarium verticillioides, predominantly present in corn. The principal biochemical responses of FB1 involve disruption of sphingolipid metabolism from the inhibition of ceramide synthesis leading to accumulation of free sphingoid bases, particularly sphinganine. The ability of FB1 to modulate signal transduction pathways plays a role in its toxicity. We recently reported that FB1 selectively and transiently activates protein kinase Calpha (PKCalpha) in porcine renal epithelial cells (LLC-PK1). The aim of current study was to investigate the effect of PKCalpha activation by FB1 on NF-kappaB activation and subsequently on TNFalpha gene expression and caspase 3 induction in LLC-PK1 cells. FB1 (1 micromol/L for 5 min) transiently activated PKCalpha and increased nuclear translocation of NF-kappaB, followed by their down-regulation at later time points. Preincubating the cells with the PKC inhibitor, calphostin C, prevented the activation of NF-kappaB by FB1. TNFalpha mRNA expression was increased after 15 min exposure to FB1 or the PKC activator, phorbol 12-myristate 13-acetate. In addition, an increase in caspase 3 activity was observed after addition of FB1 for 1 h. Calphostin C prevented both the FB1-induced increase in TNFalpha expression and caspase 3 activation. In summary, we hereby demonstrate that the FB1 activation of NF-kappaB and sequential induction of TNFalpha expression resulting in the subsequent increase in caspase 3 activity are all dependent on PKCalpha stimulation in LLC-PK1 cells.     

The mycotoxin fumonisin B1 inhibits integrin-mediated cell-matrix adhesion

Fumonisin B1 (FB1), a mycotoxin produced by the corn fungus Fusarium moniliforme, causes a variety of animal diseases and is a suspected human carcinogen. The FB1 molecule bears remarkable structural resemblance to the long-chain sphingoid base backbones of sphingolipids. The toxicity and carcinogenicity of FB1 has been ascribed to its ability to inhibit ceramide synthase, a key enzyme in the metabolism of complex sphingolipids. In this study we have investigated whether the exposure of B16-BL6 mouse melanoma cells to FB1 affects cell growth and integrin-mediated cell matrix adhesion. Cell treatment with the highest tested dose (75 microM) of FB1 for 72 h induced an about 20% inhibition of cell growth. FB1 strongly affected B16-BL6 cell adhesion to immobilized fibronectin, by causing a dose-dependent inhibition of cell attachment to this substrate. FB1 also inhibited in a dose-dependent manner the adhesion of B16-BL6 cells to the immobilized anti-fibronectin receptor antibody, whereas it affected only to a low extent cell attachment to concanavalin A. Our results demonstrate that FB1 treatment alters integrin adhesive activity, thus affecting all cellular integrin-dependent functions.     

Fumonisin- and AAL-Toxin-Induced Disruption of Sphingolipid Metabolism with Accumulation of Free Sphingoid Bases

Fumonisins (FB) and AAL-toxin are sphingoid-like compounds produced by several species of fungi associated with plant diseases. In animal cells, both fumonisins produced by Fusarium moniliforme and AAL-toxin produced by Alternaria alternata f. sp. lycopersici inhibit ceramide synthesis, an early biochemical event in the animal diseases associated with consumption of F. moniliforme-contaminated corn. In duckweed (Lemna pausicostata Heglem. 6746), tomato plants (Lycopersicon esculentum Mill), and tobacco callus (Nicotiana tabacum cv Wisconsin), pure FB1 or AAL-toxin caused a marked elevation of phytosphingosine and sphinganine, sphingoid bases normally present in low concentrations. The relative increases were quite different in the three plant systems. Nonetheless, disruption of sphingolipid metabolism was clearly a common feature in plants exposed to FB1 or AAL-toxin. Resistant varieties of tomato (Asc/Asc) were much less sensitive to toxin-induced increases in free sphinganine. Because free sphingoid bases are precursors to plant "ceramides," their accumulation suggests that the primary biochemical lesion is inhibition of de novo ceramide synthesis and reacylation of free sphingoid bases. Thus, in plants the disease symptoms associated with A. alternata and F. moniliforme infection may be due to disruption of sphingolipid metabolism.     

Simultaneous occurrence of fumonisin B1 and other mycotoxins in moldy corn collected from the People's Republic of China in regions with high incidences of esophageal cancer.

A total of 31 corn samples collected from households in the counties of Cixian and Linxian of the People's Republic of China, where high incidences of esophageal cancer have been reported, were analyzed for fumonisin B1 (FB1), aflatoxin, and total trichothecene mycotoxins. High levels of FB1 (18 to 155 ppm; mean, 74 ppm) were found in 16 of the samples that showed heavy mold contamination. FB1, at lower levels (20 to 60 ppm; mean, 35.3 ppm), was also found in 15 samples, collected from the same households, that did not show any visible mold contamination. The levels of aflatoxin in the samples were low (1 to 38.4 ppb; mean, 8.61 ppb). High levels of total type-A trichothecenes were also found in the moldy corn samples (139 to 2,030 ppb; mean, 627 ppb). Immunochromatography of selected samples revealed that these samples contained T-2 toxin, HT-2 toxin, iso-neosolaniol, monoacetoxyscirpenol, and several other type-A trichothecenes. The concentration of total type-B trichothecenes in 15 moldy corn samples was in the range of 470 to 5,826 ppb (mean, 2,359 ppb). High levels (3.7 to 5.0 mg/g) of FB1 were produced in corn in the laboratory by five Fusarium moniliforme strains isolated from the moldy corn. These fungi were also capable of forming various nitrosamines (5 to 16 micrograms per flask) in the presence of nitrate and precursor amines.(ABSTRACT TRUNCATED AT 250 WORDS)     

Fumonisins production by Fusarium proliferatum strains isolated from asparagus crown

The present work deals with the capability for producing fumonisin by Fusarium proliferatum strains isolated from asparagus in China. Fifty of F. proliferatum strains were randomly selected and incubated on cultures of maize grain and asparagus spear, respectively. Fumonisin levels (FB₁ and FB₂) were determined by high-performance liquid chromatography coupled to electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS). The results showed that all 50 strains produced fumonisins in maize culture within a wide range of concentrations, 10–11,499 μg/g and 2–6,598 μg/g for FB₁ and FB₂, respectively. On culture of asparagus spear,48 strains (96%) produced fumonisins in the range 0.2–781.6 μg/g and no detected to 40.3 μg/g for FB₁ and FB₂, respectively. All of F. proliferatum strains produced much higher levels of FB₁, FB₂ and total fumonisins (FB₁ + FB₂) in maize grain culture than in asparagus spear culture. Meanwhile, fumonisin B₃ (FB₃) was identified in all maize culture extracts and most of asparagus spear culture extracts. This is the first study carried out the fumonisin-producing ability of F. proliferatum strains isolated from asparagus in China. The information obtained is useful for assessing the risk of fumonisins contamination in asparagus spear. Electronic supplementary material The online version of this article (doi: ) contains supplementary material, which is available to authorized users.     

Design and optimization of hot-filling pasteurization conditions: Cupuaçu (Theobroma grandiflorum) fruit pulp case study

Cupua?u (Theobroma grandiflorum) is an Amazonian tropical fruit with a great economic potential. Pasteurization, by a hot-filling technique, was suggested for the preservation of this fruit pulp at room temperature. The process was implemented with local communities in Brazil. The process was modeled, and a computer program was written in Turbo Pascal. The relative importance among the pasteurization process variables (initial product temperature, heating rate, holding temperature and time, container volume and shape, cooling medium type and temperature) on the microbial target and quality was investigated, by performing simulations according to a screening factorial design. Afterward, simulations of the different processing conditions were carried out. The holding temperature (T(F)) and time (t(hold)) affected pasteurization value (P), and the container volume (V) influenced largely the quality parameters. The process was optimized for retail (1 L) and industrial (100 L) size containers, by maximizing volume average quality in terms of color lightness and sensory "fresh notes" and minimizing volume average total color difference and sensory "cooked notes". Equivalent processes were designed and simulated (P(91)( degrees )(C) = 4.6 min on Alicyclobacillus acidoterrestris spores) and final quality (color, flavor, and aroma attributes) was evaluated. Color was slightly affected by the pasteurization processes, and few differences were observed between the six equivalent treatments designed (T(F) between 80 and 97 degrees C). T(F) >/= 91 degrees C minimized "cooked notes" and maximized "fresh notes" of cupua?u pulp aroma and flavor for 1 L container. Concerning the 100 L size, the "cooked notes" development can be minimized with T(F) >/= 91 degrees C, but overall the quality was greatly degraded as a result of the long cooling times. A more efficient method to speed up the cooling phase was recommended, especially for the industrial size of containers.     

Maternal fumonisin exposure and risk for neural tube defects: mechanisms in an in vivo mouse model

BACKGROUND: Fumonisin B1 (FB1) is a mycotoxin produced by the fungus Fusarium verticillioides, a common contaminant of corn worldwide. FB1 disrupts sphingolipid biosynthesis by inhibiting the enzyme ceramide synthase, resulting in an elevation of free sphingoid bases and depletion of downstream glycosphingolipids. A relationship between maternal ingestion of FB1-contaminated corn during early pregnancy and increased risk for neural tube defects (NTDs) has recently been proposed in human populations around the world where corn is a dietary staple. The current studies provide an in vivo mouse model of FB1 teratogenicity. METHODS: Pregnant LM/Bc mice were injected with increasing doses of FB1 on GD 7.5 and 8.5, and exposed fetuses were examined for malformations. Sphingolipid profiles and (3)H-folate concentrations were measured in maternal and fetal tissues. Immunohistochemical expression of the GPI-anchored folate receptor (Folbp1) and its association with the lipid raft component, ganglioside GM1, were characterized. Rescue experiments were performed with maternal folate supplementation or administration of gangliosides. RESULTS: Maternal FB1 administration (20 mg/kg of body weight) during early gestation resulted in 79% NTDs in exposed fetuses. Sphingolipid profiles were significantly altered in maternal and embryonic tissues following exposure, and (3)H-folate levels and immunohistochemical expression of Folbp1 were reduced. Maternal folate supplementation partially rescued the NTD phenotype, whereas GM1 significantly restored folate concentrations and afforded almost complete protection against FB1-induced NTDs. CONCLUSIONS: Maternal FB1 exposure altered sphingolipid metabolism and folate concentrations in LM/Bc mice, resulting in a dose-dependent increase in NTDs that could be prevented when adequate folate levels were maintained.     

Dairy manure and tillage effects on soil fertility and corn yields

Organic amendments have received renewed attention to improve soil fertility for crop production. A randomized complete block split plot experiment was conducted to evaluate the dairy manure (DM) amendments of soil for corn (Zea mays L. cv. Monsanto 919) production under different tillage systems. Main plot treatments were no-till (NT), conventional tillage (CT), and deep tillage (DT), and subplot treatments were chemical fertilization (DM(0)), and DM at 10Mgha(-1)yr(-1) (DM(10)) and 20Mgha(-1)yr(-1) (DM(20)) with supplemental chemical fertilization. Results show that tillage and DM had significantly reduced bulk density (rho(b)) with greater porosity (f(t)) and hydraulic conductivity (K(fs)) than soils under NT and DM(0). Manuring was effective to improve soil physical properties in all tillage treatments. While manure significantly increased C sequestration, the N concentration was influenced by both tillage and manure with significant interaction. The CT significantly increased P as did the addition of manure. However, with manure, K was significantly increased in all tillage treatments. While tilled soils produced taller plants with higher grain yields, and water-use efficiency than NT soils, manuring, in contrast, increased corn harvest index. Manure exerted significant quadratic effect on corn biomass N and K uptake. The variable effects of tillage and dairy manuring on soil properties and corn growth are most probably related to "transitional period" in which soil ecosystems may have adjusting to a new equilibrium.     

Nitrogen use and carbon sequestered by corn rotations in the northern corn belt,U.S

Diversified crop rotation may improve production efficiency, reduce fertilizer nitrogen (N) requirements for corn (Zea mays L.), and increase soil carbon (C) storage. Objectives were to determine effect of rotation and fertilizer N on soil C sequestration and N use. An experiment was started in 1990 on a Barnes clay loam (U.S. soil taxonomy: fine-loamy, mixed, superactive, frigid Calcic Hapludoll) near Brookings, SD. Tillage systems for corn-soybean ( Glycine max [L.] Merr.) rotations were conventional tillage (CS) and ridge tillage (CSr). Rotations under conventional tillage were continuous corn (CC), and a 4-year rotation of corn-soybean-wheat ( Triticum aestivum L.) companion-seeded with alfalfa ( Medicago sativa L.)-alfalfa hay (CSWA). Additional treatments included plots of perennial warm season, cool season, and mixtures of warm and cool season grasses. N treatments for corn were corn fertilized for a grain yield of 8.5 Mg ha(-1) (highN), of 5.3 Mg ha(-1) (midN), and with no N fertilizer (noN). Total (1990-2000) corn grain yield was not different among rotations at 80.8 Mg ha(-1) under highN. Corn yield differences among rotations increased with decreased fertilizer N. Total (1990-2000) corn yields with noN fertilizer were 69 Mg ha-1 under CSWA, 53 Mg ha(-1) under CS, and 35 Mg ha(-1) under CC. Total N attributed to rotations (noN treatments) was 0.68 Mg ha(-1) under CSWA, 0.61 Mg ha(-1) under CS, and 0.28 Mg ha(-1) under CC. Plant carbon return depended on rotation and N. In the past 10 years, total C returned from above- ground biomass was 29.8 Mg ha(-1) under CC with highN, and 12.8 Mg ha(-1) under CSWA with noN. Soil C in the top 15 cm significantly increased (0.7 g kg(-1)) with perennial grass cover, remained unchanged under CSr, and decreased (1.7 g kg(-1)) under CC, CS, and CSWA. C to N ratio significantly narrowed (-0.75) with CSWA and widened (0.72) under grass. Diversified rotations have potential to increase N use efficiency and reduce fertilizer N input for corn. However, within a corn production system using conventional tillage and producing (averaged across rotation and N treatment) about 6.2-Mg ha(-1) corn grain per year, we found no gain in soil C after 10 years regardless of rotation.     

Effect of water activity and temperature on growth and fumonisin B1 and B2 production by Fusarium proliferatum and F. moniliforme on maize grain

S. MARIN, V. SANCHIS, I. VINAS, R. CANELA AND N. MAGAN. 1995. The effect of different water activities ( a _w, 0.968, 0.956, 0.944, 0.925) and temperature (25°C and 30°C) on colonization and production of fumonisin B₁ (FB₁) and B₂ (FB₂) on sterile layers of maize by Fusarium proliferatum and F. moniliforme isolates was determined over periods of 6 weeks. Generally, both F. moniliforme and F. proliferatum grew faster with increasing a _w and best at 30°C. All three isolates produced more FB 1 than FB₂ regardless of a _w or temperature. Very little FB₁ and FB₂ were produced at 0.925 a _w, with maximum produced at 0.956 and 0.968 a _w at both temperatures tested. Most FB₁ and FB₂ were produced by F. moniliforme (25N), followed by F. proliferatum isolates (73N and 131N). At all a _w levels and both temperatures there was an increase in FB₁ and FB₂ concentration with time. Statistical analyses of a _w, temperature, time, two- and three-way interactions showed some significant differences between isolates and FB₁ and FB₂ production.     

Effect of fumonisins on macrophage immune functions and gene expression of cytokines in broilers

Fumonisin (FB1), a mycotoxin, is produced by Fusarium moniliforme and F. proliferatum. A prevalence survey in Taiwan by our laboratory showed that there was a contamination rate of 40% in domestic animal feeds, and the average contaminated level was 4.5 mg/kg. Ninety-six birds were allotted into four treatments fed with diets containing 0 (control), 5, 10, or 15 mg/kg of FB1 for three weeks. The results showed that the growth performance was not influenced by the FB1 challenge, but relative bursa weight was significantly decreased. The activity of serum aspartate aminotransferase, and the serum levels of albumin and cholesterol were significantly elevated by the FB1 challenges. When broilers were stimulated with injection of lipopolysaccharides, mRNA abundance (determined by semi-quantitative RT-PCR) interleukin-1beta (IL-1beta), IL-2, interferon-alpha (IFN-alpha), IFN-gamma, and inducible nitric oxide synthase (iNOS) reached a plateau at 3 h, and declined at 6 h. A FB1 challenge for three weeks increased cytokine mRNA abundance in broilers. The results also showed that 15 mg FB1 per kg feed significantly inhibited the expression of IL-1beta, IL-2, IFN-alpha, IFN-gamma, but had no effect on iNOS. The macrophage functional profile was significantly changed under an exposure of 15 mg FB1 per kg for three weeks. Taken together, our results suggest that FB1 up to 15 mg/kg does not affect growth performance, but impairs some parameters of blood biochemistry and the immunocompetence in broilers.