Feed additives containing sequestrant clay minerals and inactivated yeast reduce aflatoxin excretion in milk of dairy cows

The objective was to evaluate the efficacy of 2 dietary mycotoxin sequestrants, Toxy-Nil (TN) or Unike Plus (UP), in reducing aflatoxin (AF) M₁ concentrations in milk of dairy cows challenged with dietary AF. Thirty-two mid-lactation Holstein cows were blocked by parity, days in milk, and milk yield and were randomly assigned within block to receive one of the following treatments: (1) 2.8 mg of AF/cow per d (positive control, PC), (2) 2.8 mg of AF + 100 g of TN/cow per d, (3) 2.8 mg of AF + 100 g of UP/cow per d, or (4) no AF and no additives (negative control, NC). For 7 d, treatments, dispersed in 150 g of sweet feed carrier, were top-dressed twice daily by mixing into the top portion of the TMR at each feeding. After the experimental period, cows were fed the NC diet and clearance of AFM₁ via milk was monitored for 7 d. Feed and water were available ad libitum throughout the trial. Treatments had no effect on feed intake, milk yield, milk composition, or milk somatic cell count. Relative intake of AF was similar among PC, TN, and UP, averaging 106.5, 107.6, and 102.5 ± 2.9 μg/kg of diet dry matter, respectively. Relative intake of mycotoxin sequestrants was similar between TN and UP, averaging 0.4 and 0.4 ± 0.1% of diet dry matter, respectively. Concentration and mass of AFM₁ secreted in milk and in urine were similar between TN and UP, but were lower than PC; concentrations in milk averaged 0.2, 0.3, and 0.6 ± 0.1 μg/kg, respectively, and mass secreted in milk averaged 8.1, 9.8, and 20.5 ± 1.7 μg/d. Concentrations in urine averaged 6.9, 7.4, and 14.2 ± 1.5 μg/L, respectively, and mass secreted in urine averaged 225.7, 250.8, and 521.6 ± 53.1 μg/d. Likewise, concentration and mass of free AF excreted in feces were similar between TN and UP, but were lower than PC; concentrations averaged 7.7, 8.9, and 12.4 ± 0.6 μg/kg, respectively, and mass excreted averaged 57.8, 69.6, and 95.6 ± 4.8 μg/d. Transfer of AF from feed to AFM₁ in milk was reduced by 63 and 52%, and in urine, by 57 and 52% for TN and UP, respectively. Transfer of AF from feed to free AF in feces was reduced by 38 and 26% for TN and UP, respectively. The clearance rate of AFM₁ in milk did not differ among PC, TN, and UP (46.1, 66.5, and 50.0 ± 6.7%/d, respectively). Results indicate that dietary inclusion of 100 g of TN or UP significantly reduced AFM₁ in milk of cows consuming TMR containing approximately 105 μg of AF/kg of diet dry matter. Results also suggest that both TN and UP reduced absorption of AF.

The efficacy of raw and concentrated bentonite clay in reducing the toxic effects of aflatoxin in broiler chicks

The objective of this study was to evaluate the efficacy of two adsorbents, a raw bentonite clay (RC) and a concentrated bentonite clay (CC), in ameliorating the toxic effects of aflatoxin B1 (AFB1). Results of the in vitro study (pH 3.0) indicated the CC adsorbed more AFB1 than RC (93.39 mg/g vs. 79.30 mg/g) suggesting that CC may be more effective than RC in reducing the toxic effects of AFB1. One hundred and eighty day-old straight run broiler chicks were assigned to 6 replicate pens of 5 chicks each and assigned to 6 dietary treatments from hatch to day 21. Dietary treatments included: 1) basal diet (BD) containing no AFB1 or adsorbents; 2) BD plus 0.50% RC; 3) BD plus 0.50% CC; 4) BD plus 2.0 mg AFB1/kg; 5) BD plus 2.0 mg AFB1/kg plus 0.50% RC; and 6) BD plus 2.0 mg AFB1/kg plus 0.50% CC. Dietary AFB1 concentrations were confirmed by analysis and diets were screened for other mycotoxins prior to the start of the experiment. The addition of AFB1 to the feed reduced (P < 0.05) growth performance and increased (P < 0.05) relative liver weight (RLW) and kidney weight (RKW) of chicks fed AFB1 compared to control chicks on day 21. These changes were ameliorated (P < 0.05) by the addition of RC and CC to the AFB1 diet. Mild to moderate lesions of aflatoxicosis (2.25) were observed in chicks fed AFB1 alone on day 21. The addition of both RC and CC to the AFB1 diet decreased (P < 0.05) but did not prevent liver lesions (0.92 and 1.42, respectively). Results indicate that both RC and CC were effective in reducing the toxic effects of AFB1, however the cost of processing of CC would make the RC a more economical product for reducing the effects of AFB1 in young broiler chicks.

Carryover of aflatoxins from feed to lambari fish (Astyanax altiparanae) tissues

The aim of this study was to verify the carryover of aflatoxin B₁ from feed to lambari fish. Aflatoxins (AF) were incorporated into feed, checking the levels by HPLC. Treatments were: Control, feed without toxin; A, feed + 10 µg AFB₁ kg^-1; B, feed + 20 µg AFB₁ kg^-1; and C, feed + 50 µg AFB₁ kg^-1. Juveniles of lambari fish were placed in 12 aquariums at a density of 50 fish/m². Fish were fed twice a day with extruded feed, at 5% of animal biomass. The unit sample was constituted by a pool of 10 fish. AFs B₁, B₂, G₁, G₂ and M₁ were quantified by HPLC in fish muscle and liver after 30, 60, 90 and 120 days of experiment. There was accumulation of AFs is fish liver and muscle, mainly after 90 days. Fish from treatment C had higher levels of AFB₁ in muscle when compared with the others, and AFB₁ in muscle at 120 days was similar to the levels in feed. Therefore, when lambari fish is exposed on a daily and long-term basis to AFs in feed, the regulation limits for AFs in animal feed do not guarantee safety for consumers.

Efficacy of adsorbents (bentonite and diatomaceous earth) and turmeric (Curcuma longa) in alleviating the toxic effects of aflatoxin in chicks

A study was conducted to determine the efficacy of bentonite clay (BC), diatomaceous earth (DE) and turmeric powder (TUM) in alleviating the toxic effects of aflatoxin B1 (AFB1). A total of 250 Ross-308 d-old male broiler chicks were assigned to 10 dietary treatments (5 replicates of 5 chicks) from hatch to d 21. Dietary treatments were: basal diet; basal diet plus AFB1 (2 mg) or BC (0.75%), or DE (0.75%), or TUM (200 mg/kg curcuminoids) and different combinations of AFB1, BC, DE and TUM. Feed intake (FI), body weight gain (BWG) and feed gain (FG) of the birds fed on BC or DE separately were not different from control birds. Birds fed on TUM only had similar FI and FG but lower BWG than control chicks. Aflatoxin B1 reduced FI, BWG and serum concentrations of glucose, albumin, total protein calcium, but increased FG and relative liver and kidney weights. Chicks fed on the combination of AFB1 and BC had similar FI and FG to control chicks. Chicks fed on the combination of DE and AFB1 had lower FI (23.1%) and BWG (28.6%) compared with control chicks. Chicks fed on the combination of TUM and AFB1 also had decreased FI (26.2 %) and BWG (31%) compared with control chicks. Chicks fed on the combination of AFB1, BC and TUM consumed significantly higher amounts of feed compared with chicks fed on only AF, but gained less when compared with control diet chicks. Chicks fed on the combination of AFB1, DE and TUM diet had poorer growth performance than those fed on AFB1 alone. None of the combination diets reduced the severity of liver lesions.

Occurrence of Polyphenols, Organic Acids, and Sugars among Diverse Elderberry Genotypes Grown in Three Missouri (USA) Locations

Elderberry (Sambucus spp.) is an emerging horticultural crop used in a variety of foods, wines, and dietary supplements. A better understanding of the elderberry juice complex including its putative health-promoting compounds in relation to genetic and environmental parameters is needed. A multi-location planting of nine elderberry genotypes was established in 2008 at three geographically-diverse sites in Missouri, USA. Fruits were harvested from replicated plots 2009-2011, frozen, and later prepared for laboratory analysis. Polyphenols, organic acids, and sugars were quantified by HPLC and the results evaluated for response to genotype, site, and year. The American genotypes 'Ocoee' and 'Ozark' were consistently higher in chlorogenic acids compared to other genotypes, whereas 'Ocoee' was significantly higher in rutin than 'Ozark'. The European 'Marge' was significantly higher in isoquercitrin and other flavonoids compared to most North American genotypes. Significant differences in polyphenols were also detected among sites and production years. Malic, citric, and tartaric acids varied significantly among genotypes, sites, and years, whereas succinic, shikimic, and fumaric acids generally did not. Levels of lactic, acetic, and propionic acids were negligible in most samples. The American genotype 'Ocoee' was higher in citric and tartaric acids, while lower in malic acid. The sugars glucose and fructose also responded significantly to genotype, site, and year. 'Ocoee', 'Ozark', and 'Marge' perform very well in Missouri horticulturally and appear to have additional potential as cultivars based on their unique juice characteristics.

Lipid metabolism of commercial layers fed diets containing aflatoxin, fumonisin, and a binder

Aflatoxins (AF) and fumonisins (FU) are a major problem faced by poultry farmers, leading to huge economic losses. This experiment was conducted to determine the effects of AF (1 mg/kg of feed) and FU (25 mg/kg of feed), singly or in combination, on the lipid metabolism in commercial layers and investigate the efficacy of a commercial binder (2 kg/t of feed) on reducing the toxic effects of these mycotoxins. A total of 168 Hisex Brown layer hens, 37 wk of age, were randomized into a 3 × 2 + 1 factorial arrangement (3 diets with no binder containing AF, FU, and AF+FU; 3 diets with binder containing AF, FU, and AF+FU; and a control diet with no mycotoxins and binders), totaling 7 treatments. The hens contaminated with AF showed the characteristic effects of aflatoxicosis, such as a yellow liver, resulting from the accumulation of liver fat, lower values of plasma very low-density lipoprotein and triglycerides, and higher relative weight of the kidneys and liver. Hepatotoxic and nephrotoxic effects of FU were not observed in this study. On the other hand, the FU caused a reduction in small intestine length and an increase in abdominal fat deposition. The glucan-based binder prevented some of the deleterious effects of these mycotoxins, particularly the effects of AF on hepatic lipid metabolism, kidney relative weight, and FU in the small intestine.

In vitro and in vivo efficacy of a hydrated sodium calcium aluminosilicate to bind and reduce aflatoxin residues in tissues of broiler chicks fed aflatoxin B1

The aim of this study was to determine the binding capacity of a hydrated sodium calcium aluminosilicate (HSCAS) for aflatoxin B(1) (AFB(1)), and the efficacy of the HSCAS to reduce the concentrations of residual AFB(1) and its metabolites in the liver and kidney of broilers fed AFB(1). One hundred 1-d-old male broilers (Ross 708) were maintained in chick batteries and allowed ad libitum access to feed and water. A completely randomized design was used with 5 replicate pens of 5 chicks assigned to each of 4 dietary treatments from hatch to 21 d. Dietary treatments included the following: A) basal diet (BD), with no HSCAS or AFB(1), B) BD supplemented with 0.5% HSCAS only, C) BD supplemented with 2.5 mg of AFB(1)/kg of feed, and D) BD supplemented with 2.5 mg of AFB(1)/kg of feed and 0.5% HSCAS. On d 21, 5 chicks from each treatment were anesthetized with carbon dioxide, killed by cervical dislocation, and samples of liver and kidney were collected for analysis of AFB(1) residues. The percentage of AFB(1) bound for each concentration of adsorbent (100, 10, 1, 0.5, 0.25, and 0.05 mg/10 mL) was 100, 91.1, 81.8, 75.4, 40.1, and 8.8%, respectively. Concentrations of aflatoxin residues (AFB(1), aflatoxicol, aflatoxins B(2) and G(1)) were lower (P < 0.05) in livers and kidneys of birds fed AFB(1) plus HSCAS (diet D), when compared with birds fed AFB(1) alone (diet C). However, histopathology data from the in vivo study indicated that HSCAS did not prevent lesions associated with aflatoxicosis. The decrease in the bioavailability of AFB(1) caused by the HSCAS reduced aflatoxin residues in liver and kidney, but not enough to completely prevent the toxic effects of AFB(1) in broilers.

Use of different levels of ground endophyte-infected tall fescue seed during heat stress to separate characteristics of fescue toxicosis

Studies of fescue toxicosis using whole seed diets show reduced feed intake and thermoregulatory ability, but much of the seed passes undigested through the animal. Cattle were fed ground tall fescue seed at different levels to potentially facilitate digestion and absorption of toxins and identify toxin sensitivity for major characteristics of the condition [i.e., hyperthermia, reduced feed intake (FI), reduced blood prolactin]. Steers (n = 18; 350 kg BW) were housed in the Brody Climatology Laboratory at thermoneutrality (TN; 19°C) and randomly assigned to daily diet treatments with either ground endophyte-infected [E+; low and high doses at 20 and 40 μg ergovaline/(kg BW/d), respectively] or endophyte-free [E-; control at 0 μg ergovaline/(kg BW/d)] tall fescue seed. After 12 d at TN, animals received 2 d of transition to heat stress (HS; 36°C daytime, 25°C nighttime) and maintained for 14 more days. Cattle were fed twice daily at 0800 and 1600 h, with water ad libitum. Feed intake was measured at 0700 h, with skin and rectal temperatures, and respiration rate at 0600, 1100, 1600, and 2100 h. Blood was sampled on selected days for prolactin and leptin determinations. Steers fed ground E+ diet decreased (P ≤ 0.0001) FI below controls at TN, with no dose effect. Maximum FI reduction with E+ treatment was 25% at TN, with an additional 46% decrease during HS (P ≤ 0.05). By the end of HS, E+ FI increased (P > 0.05) to that of E-, suggesting recovery. Prolactin was reduced (P ≤ 0.05) in high E+ cattle below controls at study end. Leptin blood concentrations were unaffected by E+ treatment (P > 0.05) but was reduced (P ≤ 0.05) by the end of HS. Pattern of rectal temperature response to HS showed a more rapid initial increase and decline for both E+ groups compared with controls (P ≤ 0.05). Skin temperature was the only variable that identified E+ dose differences. Although there were no treatment differences at TN, skin temperature was lower (P ≤ 0.05) for high E+ steers compared with controls during HS when air temperature was reduced each day. In general, FI was more responsive to E+ toxins than body temperature or blood prolactin, declining even at TN and exhibiting dynamic activity during HS. Although body temperature response to E+ toxins appears to stabilize during HS, this is misleading as rapid change in air temperature exposes effects on skin temperature.

Toxic interaction between fumonisin B1 and moniliformin for cardiac lesions in Japanese quail

This study examined the effects of fumonisin B1 (FB1) and moniliformin (M) on the heart of Japanese quail (Coturnix coturnix japonica). Three hundred and ninety day-old Japanese quail were randomly divided into four groups: 1) FB1 alone (FX), 2) M alone (MX), 3) FB1 and M (FM), and 4) chick mash alone (CX). We used three pen replicates of 35 quail per pen in groups FX, MX, and FM and three pen replicates of 25 quail per pen in group CX. Gross and microscopic changes in the heart were studied in nine birds (three birds per replicate) from each group at weekly intervals up to 28 days postfeeding (DPF). Ultrastructural changes were studied in the heart of three birds (one bird per replicate) from each group at 21 DPF. Thinning of the heart was the only significant gross lesion in group FX. In contrast, mild-to-severe cardiomegaly was a significant finding in groups MX and FM throughout the study. Microscopically, thinning of cardiomyocytes was evident at 7 DPF in group FX. In addition to the hypertrophy of cardiomyocytes evident as early as 7 DPF, myocardial karyomegaly, nuclear hyperchromasia, and myofibril disarray exhibiting a wavy pattern were more pronounced at 28 DPF in group MX. Similar but more severe lesions were observed in the FM combination group that included myocardial hemorrhages, vacuolar changes, hypertrophy of cardiomyocytes, focal myocarditis, and loss of myofibrils cross-striations. Via transmission electron microscopy, the maximum effect of FB1 toxicity was observed on mitochondria. In addition to an increase in the number of mitochondria, the mitochondria seemed invariably swollen and pleomorphic, although the outer membrane was intact, and the membrane cristae were usually distinct. Myofibrils seemed thinner, without much disruption in their architecture. Large numbers of vacuolar bodies of irregular size, both in the sarcoplasm and in between the myofibrils, were conspicuous in group FX. In contrast to group FX, the increase in number of mitochondria resulted in widespread separation of muscle fibers in group MX. In addition, the mitochondria were swollen and varied from round to oval to slightly elongated and occasionally forked, and vacuolation was rarely noticed in group MX. In the FM combination group, a significant increase in the number of mitochondria caused muscle fibers to look much thinner and assume a wavy pattern. We conclude that the effect of M on the heart is exaggerated in the presence of FB1. Although the overall interactive effect of FB1 and M was less than additive, the interactive effects between the two toxins for cardiac lesions were greater than additive to synergistic up to the second week, raising serious concerns on early age exposure to a combination of these two mycotoxins.

Effect of ochratoxin A on broiler chicks challenged withSalmonella gallinarum

1. A study was conducted to evaluate the effects of ochratoxin A (OA) on broiler chicks challenged with Salmonella gallinarum. 2. One hundred and seventy-six 1-d-old broiler chicks were divided into two groups of 88 chicks each, with one group fed on a control mash diet and the other given a mash diet containing 2 ppm OA. On d 14, each group was further subdivided into two groups with one group infected with S. gallinarum and the other uninfected. 3. Following S. gallinarum inoculation on d 14, 4 birds from each group were killed at 1, 2, 3, 5, 7, 10, 14 and 21 d post inoculation. 4. S. gallinarum infection caused dullness, depression, weakness, increased thirst, droopy wings, ruffled feathers and greenish-yellow diarrhoea. S. gallinarum infection in the absence of OA caused 11.5% mortality which increased to 28.8% in the presence of OA. 5. Decreased body weight and reduced feed intake were observed in chicks fed on the diet containing OA. S. gallinarum infection also reduced the body weights of chicks, with the effects being more marked in chicks receiving OA. The OA diet led to increased serum levels of aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, uric acid and creatinine, and decreased levels of total proteins, albumin, globulins, calcium and phosphorus. S. gallinarum infection did not cause significant alteration in any of the serum biochemical parameters. 6. Mortality and the severity of S. gallinarum infection in broiler chicks were increased by the presence of OA in the diet.

Effects of dietary aflatoxin on the health and performance of growing barrows

Aflatoxins, especially aflatoxin B1 (AFB1), can be greater in dried distillers grains with solubles (DDGS) because it can be concentrated during the ethanol production process. Increased use of DDGS in swine diets could potentially lead to an increased incidence of aflatoxicosis, a disease associated with decreased feed intake, reduced BW gain, and impaired liver function. The objective of this study was to determine the effects of AFB1 on the health, performance, and serum profile of growing barrows. Ninety Duroc × Yorkshire crossbred barrows were purchased (age = 35 ± 5 d; BW = 14.2 ± 3.0 kg), allocated to 9 pens with 10 pigs per pen, and randomly assigned to receive diets containing 0 µg/kg of AFB1 (CON), 250 µg/kg of AFB1 (LO), or 500 µg/kg of AFB1 (HI) for 7, 28, or 70 d in a 3 × 3 factorial arrangement of treatments. Feed intake was measured daily, and pigs were weighed and blood samples collected weekly. Serum was analyzed for concentrations of aspartate aminotransferase (AST), alanine aminotransferase (ALT), total bilirubin (BILI), and blood urea nitrogen (BUN). Both ADFI and ADG were negatively affected (P ≤ 0.001) by AFB1 treatment. Average daily feed intake was less (P < 0.05) in HI barrows than in CON barrows from wk 5 to 10 and was less (P < 0.05) in LO barrows than in CON barrows in wk 5 and again from wk 8 to 10. Also, ADFI was less (P = 0.022) in HI barrows than LO barrows in wk 10. Decreased ADG (P < 0.05) was observed in HI barrows than in CON barrows in wk 8 and 10; no differences (P ≥ 0.665) in ADG were noted between CON and LO barrows. There was no effect (P ≥ 0.080) of AFB1 treatment on ALT or BILI concentrations. However, both AST and BUN were affected (P < 0.05) by AFB1 treatment. Serum AST was greater (P = 0.010) in LO barrows than CON barrows in wk 5, and serum BUN was greater (P = 0.004) in CON barrows than LO barrows in wk 3. Results from this study demonstrate that the performance and health of young growing barrows were affected by consumption of an AFB1-contaminated diet, especially when fed for a more extended period.

Genetic variation at bx1 controls DIMBOA content in maize

The main hydroxamic acid in maize (Zea mays L.) is 2-4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one (DIMBOA). DIMBOA confers resistance to leaf-feeding by several corn borers. Most genes involved in the DIMBOA metabolic pathway are located on the short arm of chromosome 4, and quantitative trait loci (QTLs) involved in maize resistance to leaf-feeding by corn borers have been localized to that region. However, the low resolution of QTL linkage mapping does not allow convincing proof that genetic variation at bx loci was responsible for the variability for resistance. This study addressed the following objectives: to determine the QTLs involved in DIMBOA synthesis across genetically divergent maize inbreds using eight RIL families from the nested association mapping population, to check the stability of QTLs for DIMBOA content across years by evaluating two of those RIL families in 2 years, and to test the involvement of bx1 by performing association mapping with a panel of 281 diverse inbred lines. QTLs were stable across different environments. A genetic model including eight markers explained approximately 34% of phenotypic variability across eight RIL families and the position of the largest QTL co-localizes with the majority of structural genes of the DIMBOA pathway. Candidate association analysis determined that sequence polymorphisms at bx1 greatly affects variation of DIMBOA content in a diverse panel of maize inbreds, but the specific causal polymorphism or polymorphisms responsible for the QTL detected in the region 4.01 were not identified. This result may be because the causal polymorphism(s) were not sequenced, identity is masked by linkage disequilibrium, adjustments for population structure reduce significance of causal polymorphisms or multiple causal polymorphisms affecting bx1 segregate among inbred lines.

The effects of zearalenone on reproduction in swine. I. The relationship between ingested zearalenone dose and anestrus in non-pregnant, sexually mature gilts

Ninety-nine sexually mature, non-pregnant gilts were checked for estrus daily with a mature boar and then allocated at estrus (D O) to receive 2 kg/d of a diet containing 0, 1, 5 or 10 ppm purified zearalenone between D 5 and 20 of the estrous cycle during two seasons of the year (winter and summer). None of the gilts exhibited any visual signs of "hyperestrogenism" and there was no effect of season on interestrous interval (P>0.05). A significant effect of zearalenone dose on inter-estrous interval was detected (P<0.001). Gilts receiving 0 or 1 ppm had similar inter-estrous intervals (21.0+/-0.3 and 21.5+/-0.8 d, respectively) whereas gilts receiving 5 and 10 ppm had extended cycles (29.2+/-2.9 and 32.7+/-3.3 d, respectively). Plasma progesterone concentrations at D 19 to 21 were higher in gilts with extended cycles (P<0.001) and corpora lutea (CL) were present at laparotomy. Some 86% of these retained CL underwent spontaneous regression resulting in the onset of estrus within the next 30 d. Fecal zearalenone concentrations rose during ingestion of contaminated diets and declined to pretreatment values within 2 d (1 ppm) to 8 d (10 ppm) of the cessation of treatment. These data show that feeding zearalenone at concentrations of 5 to 10 ppm from D 5 to 20 of the estrous cycle causes luteal maintenance and extended inter-estrous intervals. Spontaneous regression of these CL usually occurs within 30 d after zearalenone is removed from the diet. Fecal zearalenone analysis does not appear to be an effective method for determining prior exposure to zearalenone when carried out more than a few days following the last ingestion of zearalenone.

Influence of toxic endophyte-infected fescue on sperm characteristics and endocrine factors of yearling Brahman-influenced bulls

Sixteen (mean age = 1.1 +/- 0.1 yr; mean BW = 478 +/- 34 kg) Brahman-influenced bulls were used to determine the influence of fescue type on sperm characteristics and serum concentrations of prolactin, cortisol, and testosterone. Bulls were blocked by BW, scrotal circumference (SC), and pregrazing sperm characteristics and randomly assigned to graze toxic endophyte-infected (EI; 4 bulls/pasture; 2 pastures) or novel endophyte-infected (NE; 4 bulls/pasture; 2 pastures) tall fescue for 121 d. Semen was collected by electroejaculation, and SC was measured and blood samples collected monthly. Sperm were evaluated for motility and morphology with an integrated visual optical system. Overall mean concentration of prolactin was decreased more (P < 0.01) in EI bulls than NE bulls from May to August. Scrotal circumference was not affected by fescue type (P = 0.58); overall SC averaged 36.7 +/- 2.3 cm. Percentage of live sperm was not different (P = 0.24) between NE bulls (80%) than EI bulls (67%) in July and August. Bulls grazing NE fescue had more (P < 0.06) motile sperm than EI bulls in July and August. Percentages of progressive (57 vs. 38%, NE and EI, respectively; P < 0.06) and rapid (67 vs. 46%, NE and EI, respectively; P = 0.04) sperm were greater from bulls grazing NE than EI bulls in July and August. Average velocity of the smoothed sperm path and progressive velocity in a straight line from the beginning to the end of the sperm track were slower (P < 0.09) in EI bulls than NE bulls and were slower (P = 0.04) in August compared with July. Mean width of head oscillation as the sperm swims was less (P < 0.06) in August than July. Concentrations of cortisol and testosterone were not (P > 0.10) influenced by fescue type. Semen from bulls grazing EI had reduced motility and morphology than bulls grazing NE. Detrimental effects of toxic fescue may not be mediated by cortisol, testosterone, or both. Semen quality of bulls grazing toxic EI tall fescue was decreased with increased maximum ambient temperatures.

Individual and combined effects of fumonisin b1 and moniliformin on clinicopathological and cell-mediated immune response in Japanese quail

A total of 390 one-day-old quail chicks (Coturnix coturnix japonica) were divided into 4 groups (3 replicates per treatment), viz. CX, FX, MX, and FM, containing 75, 105, 105, and 105 birds, respectively. Birds in the control group (CX) were fed quail mash alone, whereas birds in group FX were fed 200 ppm of fumonisin B(1) (FB(1)) from Fusarium verticillioides culture material; group MX was fed 100 ppm of moniliformin (M) from Fusarium fujikuroi culture material; and group FM was fed a combination of 200 ppm of FB(1) and 100 ppm of M. Diets were fed from d 1 to 35 to study clinical signs, growth response, serum biochemical changes, and cell-mediated immune response. Birds fed FB(1) (FX) showed ruffled feathers and poor growth. Birds in group MX appeared more stunted than those in group FX and exhibited signs of poor feathering and decreased feed and water intake. Clinical signs observed in group FM were more or less similar to those observed in groups FX and MX. Total mortality was 12.38, 7.62, and 20.95% for groups FX, MX, and FM, respectively. Mean BW in groups FX, MX, and FM were significantly lower than those in the control group (CX) at almost all intervals. Total serum proteins, albumin, cholesterol, aspartate transaminase, lactate dehydrogenase, and creatine kinase values were higher in all treatment groups compared with the control group. Cell-mediated immune response was more or less comparable in groups CX and MX, whereas the presence of FB(1) in the diet of groups FX and FM was found to be associated with a gradual increase in skin thickness, and the mononuclear inflammatory cell response was poor as compared with groups CX and MX throughout the study. Except for mortality (additive effect) and serum aspartate transaminase values (less than an additive effect up to 14 DPF), no additive or synergistic effects were observed for any of the other response variables measured in the current study, where all statistical differences were attributed to either one mycotoxin or the other.

Effects of aflatoxin B1and fumonisin B1on body weight, antibody titres and histology of broiler chicks

1. Our objective was to evaluate the toxic effects of aflatoxin B1 (AFB1) and fumonisin B1 (FB1), administered singly or in combination to broilers. 2. Feeds were prepared with concentrations equal to 0, 50 and 200 microg AFB1/kg, and/or 0, 50 and 200 mg FB1/kg, and offered to broiler chicks from 8 to 41 d of age. The experimental design was totally randomised, in a 3 x 3 factorial arrangement with 9 treatments and 12 birds per treatment. Animals were vaccinated against Newcastle disease on d 14 of life and killed at 41 d. 3. Compared with controls, all mycotoxin-treated groups at 41 d had lower body weight and weight gain, and higher relative heart weight. The relative weight of the liver increased only in birds fed diets containing 200 mg FB1, singly or in combination with AFB1. 4. At 35 d, all groups receiving mycotoxin-treated rations had reduced geometrical mean antibody titres, with birds from groups fed combinations of AFB1 and FB1/kg having even lower values, when compared to the other groups. 5. Histological changes were observed only in liver from birds fed mycotoxin-contaminated rations, and in kidneys of birds fed the diet containing 200 microg AFB1 and 200 mg FB1/kg. Main alterations included vacuolar degeneration and cell proliferation of bile ducts in the liver, and hydropic degeneration in renal tubules in the kidneys. 6. We concluded that AFB1 and FB1 in combination have primarily additive effects on body weight, liver structure and immunological response of broilers at the concentrations used.

In Vitro and In Vivo Assessment of Humic Acid as an Aflatoxin Binder in Broiler Chickens

The in vitro affinity and adsorption capacity of a humic acid, oxihumate, for aflatoxin B1 (AFB1) was evaluated, utilizing Langmuir and Freundlich adsorption isotherms. Oxihumate showed a high in vitro affinity for AFB1. The Freundlich isotherm fitted the data better than the Langmuir isotherm, and binding capacities of 10.3, 7.4, and 11.9 mg of AFB1/g of oxihumate at pH 3, 5, and 7, respectively, were calculated. The in vivo efficacy of oxihumate as an aflatoxin binder in male broiler chickens exposed to aflatoxin-contaminated feed from 7 to 42 d of age was also assessed. The efficacy of oxihumate was compared with a commercially available product with a brewers dried yeast (BDY) and brewers fermentation solubles as main active ingredients. A total of 420 birds were assigned to 28 pens, with 15 birds per pen. The following treatments were applied: 1) 0 mg of AFB1 + 0 additives, 2) 1 mg of AFB1/kg of feed + 0 additives, 3) 1 mg of AFB1/kg of feed + 3.5 g of oxihumate/kg of feed, 4) 1 mg of AFB1/kg of feed + 3.5 g of BDY/kg of feed, 5) 2 mg of AFB1/kg of feed + 0 additives, 6) 2 mg of AFB1/kg of feed + 3.5 g of oxihumate/kg of feed, and 7) 2 mg of AFB1/kg of feed + 3.5 g of BDY/kg of feed. Each treatment consisted of 4 replicates. Oxihumate was effective in diminishing the adverse effects caused by aflatoxin on BW of broilers (P < 0.05). Oxihumate also showed protective effects against liver damage, stomach and heart enlargement, as well as some of the hematological and serum biochemical changes associated with aflatoxin toxicity (P < 0.05). Results indicated that oxihumate, but not BDY, could alleviate some of the toxic effects of aflatoxin in growing broilers. Oxihumate might, therefore, prove to be beneficial in the management of aflatoxin-contaminated feedstuffs for poultry when used in combination with other mycotoxin management practices. Additional studies are warranted to assess its efficacy under a wide variety of circumstances.

Effects of feeding Fusarium verticillioides (formerly Fusarium moniliforme) culture material containing known levels of fumonisin B1 in Japanese quail (Coturnix coturnix japonica)

One hundred fifty 1-d-old quail chicks (Coturnix coturnix japonica) were divided into 2 groups. The 2 groups were designated as controls (CX) and fumonisin-fed birds (FX) with each containing 50 and 100 chicks, respectively. The birds in group CX were maintained on quail mash alone, whereas the birds in group FX were maintained on diets supplemented with 300 ppm of fumonisin B1 from Fusarium verticillioides (formerly Fusarium moniliforme) culture material from 1 d. Quail chicks in both groups were examined daily for clinical signs and mortality. Five randomly selected quail from each group were individually weighed on 0, 7, 14, 21, and 28 d post-feeding (DPF). After weighing, blood was collected from these birds at 7, 14, 21, and 28 DPF for hematological studies and at 14, 21, and 28 DPF for biochemical studies. Fumonisin B1-fed birds (FX) had ruffled feathers, reduced feed and water intake, poor body growth, and greenish mucus diarrhea with 59% mortality. Nearly 30% of the fumonisin B1-fed birds showed nervous signs during the 4-wk experimental period. From 7 DPF onward, BW in group FX were significantly lower than those in group CX. Fumonisin feeding significantly increased hemoglobin, packed cell volume, total erythrocyte count, and total leukocyte count. There was also a significant increase in aspartate transaminase and alanine transaminase in the fumonisin-fed group. Fumonisins significantly increased concentrations of total serum protein and albumin on 14 and 21 DPF, serum calcium and cholesterol levels from 14 DPF onward, and creatinine from 21 DPF onward. This study revealed that the addition of F. verticillioides culture material supplying a level of 300 ppm of FB1/kg of diet is highly toxic to quail chicks, resulting in heavy mortality, decreased growth rate, and significant alterations in hemato-biochemical parameters.

Widespread Occurrence of Ergot in Upper Midwestern U.S. Barley, 2005

Ergot, caused by Claviceps purpurea (Fr.) Tul., occurs every year on cereals and grasses in North Dakota, but the occurrence on barley (Hordeum vugare L) is generally sporadic with a very low incidence of sclerotia. Disease surveys conducted during the 2005 growing season revealed an unusually widespread occurrence. This is of concern since barley production in North Dakota was estimated at 1.25 million metric tons, 27% of the total 2005 U.S. production. Barley samples (n = 304, ~0.50 kg) collected in all crop-reporting districts of North Dakota, northwestern Minnesota, and northeastern Montana, as part of an annual regional survey of barley crop quality (4), were examined for sclerotia. All barley samples were cleaned for dockage, and ergot (% [w/w]) was estimated on subsamples of ~100 g from a sample divider. Of all barley samples collected, 62% contained ergots. The regional average for ergot infested kernels was 0.06%, and samples ranged from <0.01 to 1.19%. Approximately 15% of all samples were in excess of 0.10% ergots and would have been downgraded to ergoty barley under the Official United States Standards for Grain. Occurrence of ergot was most common in northwestern Minnesota and the three eastern and north-central districts of North Dakota. Ergot was less frequent in the south-central and three western districts of North Dakota and was not detected in samples from northeastern Montana. Floret infection occurs during and up to 15 days after anthesis (2), and in the three eastern and north-central districts of North Dakota that occurred around the last week in June and first week in July. Between 22 June and 4 July, the North Dakota Agricultural Weather Network Stations in that region recorded average daily temperatures of 99% of the 30-year norm, but multiple precipitation events amounted to 227% of the 30-year norm. Rain splash and associated high relative humidity favor conidiation and spread of the fungus (1) and may have contributed to the high disease incidence. Average sclerotia weight for a sample ranged from <10 to 70 mg. However, large sclerotia (37 to 180 mg) often were removed by the no. 6 riddle of the dockage tester and were not counted in the ergot estimates as per U.S. Grading Standards. Samples containing 1.19, 0.81, 0.22, 0.14, 0.05, and 0.02% ergots were analyzed for ergopeptine alkaloids (3). These were found to contain 27.9, 25.4, 2.4, 1.1, 1.7, and 5.7 μg/g ergopeptine alkaloids, respectively. The average ratio of ergosine/ergotamine/ergocornine/ergocryptine/ergocristine was approximately 1:2:2:3:9. There also was widespread occurrence of the Fusarium mycotoxin deoxynivalenol (DON) on North Dakota barley in 2005. While there was no apparent relationship between the level of the DON and the amount of ergot in the samples (r = 0.042), more than 90% of samples with ergot had detectable levels (0.1 to 69 μg/g) of DON. While only DON is routinely measured in the crop survey (4), other tricothecenes and zearalenone have also been detected. This should be of concern to livestock producers and grain processors since the potential interactions of multiple mycotoxins are not well known. References: (1) G. M. Marshall. Ann. Appl. Biol. 48:19, 1960. (2) S. B. Puranik and D. E. Mathre. Phytopathology 61:1075, 1971. (3) G. E. Rottinghaus et al. J. Vet. Diag. Invest. 5:242 1993. (4) P. B. Schwarz et al. J. Am. Soc. Brew. Chem. 64:1, 2006.

Individual and Combined Effects of Fusarium moniliforme Culture Material, Containing Known Levels of Fumonisin B1, and Salmonella Gallinarum Infection on Liver of Japanese Quail

Three hundred day-old Japanese quail (Coturnix coturnix japonica) were divided into two groups with 150 quail in each group. One group was maintained on quail mash alone, while Fusarium moniliforme culture material was added to quail mash in the second group from day 5 of age and was supplied at a rate of 150 ppm fumonisin B1 (FB1)/kg mash. At day 21, each group was further subdivided into two groups, yielding four groups with 75 birds apiece, which served as the control (group CX), the Salmonella Gallinarum alone group (group CS), the FB1 alone group (group FX), and the group fed FB1 and infected with Salmonella Gallinarum (group FS). An oral challenge with Salmonella Gallinarum organisms (2 x 10(4) colony-forming units/ml) was given to groups CS and FS at 21 days of age. Three quail each were necropsied on day 21 (0 day interval) from groups CX and FX only. At subsequent intervals (i.e., 1, 2, 3, 5, 7, 10, 14, and 21 days postinfection [DPI]), three quail were euthanatized from all four groups (CX, CS, FX, and FS). The gross and microscopic lesions were recorded in both mortality and euthanatized birds at the above intervals. The ultrastructural studies were done at 5 DPI. Mild to moderate hepatomegaly and pale discoloration of liver were observed in group FX, while congestion, hemorrhages, necrosis, and mild to severe hepatomegaly were the predominant gross lesions in both infected groups (CS and FS). The gross lesions in quail inoculated with Salmonella Gallinarum alone (group CS) generally developed slowly, appeared more widely scattered, and involved comparatively less surface area in contrast to the rapidly progressive and frequently confluent lesions in the combination group (FS), especially in the first 5 days of infection. Mild to marked hepatocellular swelling, multifocal hepatic necrosis, and hepatocellular and bile duct hyperplasia were the characteristic microscopic changes in the FX group. Microscopic lesions in quail of group CS comprised congestion, vacuolar changes, and focal necrosis in early stages, followed by granulomatous lesions at later intervals. Similar but more severe lesions were observed in the combination group (FS). Based on transmission electron microscopy, the maximum effect of FB1 toxicity was observed on mitochondria and endoplasmic reticulum. In general, the mitochondriae showed diverse form and structure, some of which appeared to lose their intact outer membrane, and the mitochondrial cristae were disoriented. The deformity in the cisternae structure of rough endoplasmic reticulum, with their rearrangement into round or tubular forms either bearing granular surface or leading to accumulation of smooth endoplasmic reticulum, was evident only in groups FX and FS. We conclude that the continuous presence of fumonisins in the diets of young quail might increase their susceptibility to or the severity of Salmonella Gallinarum infection.

Effects of Fusarium moniliforme culture material containing known levels of fumonisin B1 on progress of Salmonella Gallinarum infection in Japanese quail: clinical signs and hematologic studies

To study the individual and combined effects of fumonisin B1 (FB1) toxicity and Salmonella serotype Gallinarum infection, Japanese quail (Coturnix coturnix japonica) were fed Fusarium moniliforme culture material (2.5%), 150 mg FB1/kg ration, and were subsequently challenged orally with Salmonella Gallinarum organisms (2 x 10(4) colony-forming units) at 21 days of age. The chicks were fed culture material containing FB1 from day 5 till the end of the experiment. After being infected with Salmonella Gallinarum, observations were made 1, 2, 3, 5, 7, 10, 14, and 21 days postinfection. The clinical signs of diarrhea with bloody discharges were more pronounced in the Salmonella-infected birds on the FB1 diet. Mortality caused by Salmonella Gallinarum increased by 12% in the presence of FB1. Mean body weights in both the Salmonella-infected and FB1-fed groups were significantly lower than those of the controls at almost all intervals. Mean values of hemoglobin, packed cell volume, and total erythrocyte count were slightly higher in birds fed FB1 but were lower in the Salmonella Gallinarum groups fed FB1 and plain chick mash. Anemia was evident, between 5 and 10 days postinfection, in quail chicks infected with Salmonella Gallinarum alone. Total leukocyte counts were higher in Salmonella-infected and FB1-fed groups because of an increase in the number of heterophils and lymphocytes. However, the increase in lymphocyte response to infection was lower by 4.27%-30.09% between 3 and 21 days postinfection in the FB1-fed chicks compared with chicks infected with Salmonella Gallinarum. Alanine transaminase and total serum protein were slightly higher in both the infected and FB1-fed groups. This study revealed that the continuous presence of fumonisins in the diets of quail chicks might increase the susceptibility to or the severity of Salmonella Gallinarum infection.

Claviceps cyperi, a new cause of severe ergotism in dairy cattle consuming maize silage and teff hay contaminated with ergotised Cyperus esculentus (nut sedge) on the Highveld of South Africa

During December/January 1996/97 typical summer syndrome (hyperthermia and a 30% drop in milk yield) occurred in succession in two Holstein dairy herds (n=240 and n=150 milking cows, respectively) on the South African Highveld. These farms are situated in the midst of the prime maize and dairy farming areas of South Africa where this condition had never been diagnosed before. The individual components of the concentrate on both farms were negative for ergot alkaloids. Endophytic fungi and/or ergot infestation of teff and other grasses fed to the cows were then suspected of being involved, but neither endophytes nor ergot alkaloids could be implicated from these sources. By measuring the serum prolactin levels of groups of sheep (n=5) fed the first farm's total mixed ration (TMR) or its three individual fibre components for a period of 11 days, the source of the ergot alkaloids was identified. A statistically significant decrease in the level of this hormone occurred only in the group on maize silage (which constituted 28% on dry matter base of the TMR). The involvement of the maize silage was further chemically confirmed by the high levels of total ergot alkaloids, predominantly ergocryptine, found by LC-MS in the silage as well as in the TMR (115-975 ppb and 65-300 ppb, respectively). The ergot alkaloid content (mainly ergocryptine) of the maize silage on the second affected farm was 875 ppb. Withdrawal of contaminated silage resulted in gradual recovery of stock on both farms. Nut sedge (Cyperus esculentus and Cyperus rotundus of the family Cyperaceae) has a world-wide distribution and is a common weed in annual crops, and can be parasitized by Claviceps cyperi. Careful examination of the maize silage from both farms revealed that it was heavily contaminated with nut sedge and that it contained minute sclerotia, identified as those of Claviceps cyperi, originating from the latter. Nut sedge was abundant on both farms and it is believed that late seasonal rain had resulted in mature, heavily ergotised nut sedge being cut with the silage. Claviceps cyperi sclerotia, collected on the affected fields in the following autumn contained 3600-4000 ppm ergocryptine. That the dominant alkaloid produced by this particular fungus was indeed ergocryptine, was confirmed by negative ion chemical ionization MS/MS. In one further outbreak in another Holstein herd, teff hay contaminated with ergotised nut sedge and containing 1200 ppb alkaloids, was incriminated as the cause of the condition. This is the first report of bovine ergotism not associated with the Poaceae infected with Claviceps purpureum or endophytes but with the family Cyperaceae and this particular fungal phytopathogen.

A model of fescue toxicosis: Responses of rats to intake of endophyte-infected tall fescue1,2

A study was conducted to develop a model for fescue toxicosis using rats fed a diet containing endophyte-infected tall fescue seed (E+). Rats implanted with telemetric transmitters to continuously monitor core body temperature (Tc) and activity were housed at thermoneutrality (21 degrees C) and were fed a diet containing endophyte-free fescue seed (E-). After 2 wk, they were assigned to either E+ or E- diets and initially maintained at thermoneutrality (preheat) for 8 d. They were then exposed to heat stress (31 degrees C) for 22 d, followed by 1 wk of recovery at thermoneutrality (post-heat). Body weight and feed intake were measured daily. Rats receiving the E+ diet showed decreased feed intake (P = 0.001) and weight gains (P = 0.003) during the preheat period. The decrease in Tc from the pre-treatment level was greater in E+ than in E- rats during the preheat (P = 0.001) and postheat (P = 0.001) periods. With heat stress, both groups showed parallel decreases in feed intake. The increase in Tc from pre-heat to heat conditions was greater in E+ vs. E- rats (P = 0.001). Activity level was lower in E+ than in E-rats during heat stress (P = 0.009) and postheat (P = 0.037) periods. These results show that the rat model for fescue toxicosis is extremely useful because many of the observed responses to E+ diet are similar to those noted for cattle, and additional variables that are difficult to measure in cattle, such as activity, can be easily evaluated.

Effect of dietary fumonisin B1 on laying Japanese quail

1. A 28-d experiment was conducted to evaluate the effects of fumonisin B1 (FB1) on egg production and egg quality of young laying Japanese quail fed on fumonisin-contaminated rations. 2. To this end, 128 7-week-old birds were randomly distributed into 4 experimental groups (32 birds per group) and given rations containing 0 (control), 10, 50 and 250mg FB1/kg feed. Each treatment consisted of 4 replicates of 8 quail. Egg production and egg weight were checked daily. Feed consumption and feed conversion were determined weekly. Eggs laid on the last day of each 7-d period were collected and subjected to individual analysis for specific gravity, Haugh units and percentage eggshell. 3. Compared with controls, quail given > or = 50 mg FB1/kg had reduced feed intake and lower body weight gain. Feed conversion was reduced only in birds given 250 mg FB1/kg. 4. Mean egg production and egg weight were lower in birds given 250mg FB1/kg. Eggshell weight was reduced in birds given > or =50mg FB1/kg. However, mean specific gravity, Haugh units and percentage eggshell were not affected by FB1. 5. No histopathological changes were observed in liver, kidney or heart samples from any treatment group. 6. The results indicated that exposure to FB1 at concentrations > or = 50 mg/kg could adversely affect quail performance, emphasising the importance of controlling fumonisin contamination of quail rations.

Effects of prolonged administration of aflatoxin B1 and fumonisin B1 in laying Japanese quail

In the present study, 288 8-wk-old Japanese quail were randomly distributed into 6 experimental groups (48 birds per group) and fed the following diets for 140 d: 1) 0 (control); 2) 10 mg of fumonisin B1 (FB1); 3) 50 microg of aflatoxin B1 (AFB1); 4) 50 microg of AFB1 + 10 mg of FB1; 5) 200 microg of AFB1; and 6) 200 microg of AFB1 + 10 mg of FB1/kg of feed. Each treatment consisted of 4 replicates of 12 quail. Egg production and individual egg weight were checked daily. Feed intake and feed conversion were determined weekly. Results showed that by the end of the fifth cycle, average egg weight was lower (P < 0.05) in groups fed 10 mg of FB1/kg, 50 microg of AFB1/kg, 200 microg of AFB1/kg, and 10 mg of FB1 + 50 microg of AFB1/kg of feed. Egg production decreased (P < 0.05) in birds fed 10 mg of FB1/kg by the third, fourth, and fifth cycles. Feed intake was lower (P < 0.05) in birds fed 10 mg of FB1/kg by the fourth and fifth cycles, and in birds fed 50 and 200 microg of AFB1/kg in the fifth cycle. Birds fed 10 mg of FB1 + 50 microg of AFB1/kg consumed less feed (P < 0.05) in the first, second, and fifth cycles. Results indicated that prolonged administration of FB1 and AFB1, singly or in combination at the levels evaluated, may cause economic losses to quail egg producers.

Anti-protozoal efficacy of high performance liquid chromatography fractions of Torilis japonica and Sophora flavescens extracts on Neospora caninum and Toxoplasma gondii

We previously reported that alcoholic extracts of Sophora flavescens and Torilis japonica from South Korea demonstrated good efficacy in reducing replication of Toxoplasma gondii and Neospora caninum. To characterize the chemical component associated with anti-protozoal activity, specific fractions were isolated by high performance liquid chromatography (HPLC) and used for in vitro testing. These fractions were evaluated in vitro against T. gondii and N. caninum. Fractions of the herb extracts were serially diluted to final concentrations of 2.850 to 0.356 ng/ml in medium and added to wells containing replicating T. gondii and N. caninum. To determine the ability of each fraction to inhibit parasite proliferation, 3H-uracil incorporation was used to determine parasite replication. In cultures infected with T. gondii, a fraction of T. japonica (TJ2) inhibited T. gondii proliferation by 99.2, 94.4, 88.6 and 27.0% in the range from 2.850 to 0.356 ng/ml. Four fractions of S. flavescens (SF1-SF4) inhibited T. gondii proliferation by 99.6-60.6, 96.9-48.1, 92.3-68.2 and 95.4-52.9% in the range from 2.850 to 0.356 ng/ml. In cultures infected with N. caninum, a fraction of T. japonica (TJ2) inhibited N. caninum proliferation by 98.3, 95.5, 79.7 and 30.6% in the range from 2.850 to 0.356 ng/ml. Four fractions of S. flavescens (SF1-SF4) inhibited N. caninum proliferation by 97.1-25.9, 94.8-35.5, 95.9-33.7 and 95.4-49.4% in the range from 2.850 to 0.356 ng/ml. These fractions of T. japonica and S. flavescens extracts are currently undergoing in vivo evaluation in experimentally infected mice.

Gangrenous ergotism in cattle grazing fescue (Festuca elatior L.) in South Africa

The 1st outbreak of fescue toxicosis in South Africa was recently confirmed in a Brahman herd at Perdekop, near Standerton, in Mpumalanga province, South Africa. Within 3 weeks of being placed on a fescue pasture in mid-winter, 50 of 385 cattle developed lameness and/or necrosis of the tail. The farmer had established Festuca elatior L. (tall fescue, Iewag variety) on c. 140 ha for winter grazing. Fescue may be infected by an endophyte, Neotyphodium coenophialum, which produces ergot alkaloids, in particular ergovaline. Ergovaline concentrations in basal leaf sheaths and grass stems collected during the outbreak ranged from 1720-8170 ppb on a dry-matter basis.

Efficacy of a commercial mycotoxin binder in alleviating effects of ochratoxin A, fumonisin B1, moniliformin and zearalenone in adult mink

The addition of nutritionally inert adsorbents to mycotoxin-contaminated animal feed has been a popular approach to decreasing toxicity in animals and carryover of mycotoxins from contaminated feed to animal by-products. Some studies suggest that esterified glucomannan derived from the cell wall of Saccharomyces cerevisiae is effective in reducing the bioavailability of at least some of the mycotoxins occurring in contaminated feed. Because cereal grains are important components of ranch mink diets, mycotoxicoses in mink is a potential problem faced by mink ranchers. We conducted a series of studies to determine if inclusion of a commercially available esterified glucomannan in ranch mink feed was effective in alleviating clinical signs indicative of exposure to ochratoxin A, fumonisin B1, moniliformin or zearalenone in adult mink. In 4 separate trials, mink were fed diets that contained 2.5, 5 or 10 mg ochratoxin A/kg feed, 200 mg fumonisin B1/kg feed, 20 mg moniliformin/kg feed, or 30 mg zearalenone/kg feed with or without 2 g esterified glucomannan/kg feed. Male mink fed diets containing ochratoxin A had significantly decreased feed intake as well as renal lesions characteristic of exposure to that mycotoxin. Inclusion of the esterified glucomannan did not ameliorate these effects. Male mink exposed to fumonisin B1 had increased urinary sphinganine concentration, which was not significantly reduced by the mycotoxin adsorbent. Male mink that consumed monilformin-contaminated diets had characteristic ultrastructural changes in the heart that were not reduced in severity by the esterified glucomannan. Female mink exposed to zearalenone had increased uterine weight, which was not reversed by inclusion of commercial mycotoxin binder in the contaminated feed. The results of this study suggest that a commercial esterified glucomannan was generally ineffective in alleviating effects indicative of exposure to ochratoxin A, fumonisin B1, monilformin and zearalenone in mink.

Individual and combined effects of the Fusarium mycotoxins fumonisin B1 and moniliformin in broiler chicks

The individual and combined effects of feeding fumonisin B1 (FB1; 0, 100, 200 mg FB1/kg) and moniliformin (M; 0, 100, 200 mg M/kg) were evaluated using a 3 x 3 factorial arrangement of treatments. Significant mortality (P < 0.05) occurred in chicks fed all diets containing 200 mg M/kg (50%-65%). Compared with controls and chicks fed FB1, both feed intake and body weight gain were decreased (P < 0.05) in chicks fed diets containing 100 mg M/kg. Chicks fed M had heavier heart weights (P < 0.05) than control chicks or chicks fed FB1. Compared with controls, chicks fed diets containing 200 mg M/kg or a combination of 200 mg FB1/kg and 100 mg M/kg had increased kidney and liver weights (P < 0.05). Significant FB1 by M interactions (P < 0.05) were observed for serum total protein and aspartate aminotransferase. Mild to moderate periportal extramedullary hematopoiesis and mild focal hepatic necrosis were observed in chicks fed FB1 alone. An increased incidence of large pleomorphic cardiomyocyte nuclei, loss of cardiomyocytes, and mild focal renal tubular mineralization were observed in chicks fed M alone. Both cardiac and renal lesions were observed in chicks fed combinations of FB1 and M. Data indicate FB1 and M, alone or in combination, can adversely affect chick performance and health at these dietary concentrations. The interactive effects of FB1 and M were not synergistic and were less than additive in nature. At the dietary concentrations studied, M is much more toxic to broilers than FB1.

Dietary soy phytoestrogens and ERalpha signalling modulate interferon gamma production in response to bacterial infection

Diets rich in soy phytoestrogens have many potential health benefits but isoflavones such as genistein may suppress cell mediated immune function. The effect of dietary phytoestrogens on the host response to infection has not been extensively examined. Mice were fed a diet containing soy phytoestrogens and infected with Mycobacterium avium to establish a chronic infection and inflammatory response. As phytoestrogens may act through classical oestrogen receptors (ER), mice deficient in ERalpha signalling and wild type mice were evaluated for a panel of Type 1-associated cytokines (IFNgamma, IL-12 and IL-18) in the spleen. IFNgamma production in the spleen was increased approximately 4-fold in ERalpha-deficient mice fed a casein-based diet over wild type mice fed a casein-based diet (P < 0.05), suggesting a role for ERalpha in suppressing IFNgamma production. IL-18 levels in spleens of wild type mice were decreased compared to ERalpha-deficient mice on a casein diet. Splenic IL-12 and IL-18 levels were not affected in wild type and ERalpha-deficient mice on the phytoestrogen containing diets, with the exception that whole soy increased IL-12 levels in the tissues of ERalpha deficient mice. We conclude that ERalpha and dietary phytoestrogens can influence production of key regulatory cytokines in response to chronic bacterial infection.

Anti-protozoal efficacy of medicinal herb extracts against Toxoplasma gondii and Neospora caninum

The purpose of this study was to determine whether alcohol extracts of herbs (Sophora flavescens Aiton, Sinomenium acutum (Thunb.) Rehder and E.H. Wilson, Pulsatilla koreana (Yabe ex Nakai) Nakai ex T. Mori, Ulmus macrocarpa Hance and Torilis japonica (Houtt.) DC.) from South Korea, possess in vitro anti-protozoal activity against cultures of Toxoplasma gondii and Neospora caninum. These herbs have been used as human anti-parasitics in Asian countries for many years. Alcohol extracts of these herbs were serially diluted to final concentrations ranging from 625 to 19.5 ng/ml in media and added to wells containing either T. gondii or N. caninum tachyzoites in equine dermal (ED) cells. Parasite growth inhibition was measured using 3H-uracil incorporation as compared to untreated controls. T. japonica inhibited T. gondii proliferation by 99.3, 95.5, 73.0 and 54.0% in the range from 156 to 19.5 ng/ml, and S. flavescens inhibited T. gondii proliferation by 98.7, 83.0 and 27.2% in the range from 156 to 39 ng/ml. T. japonica inhibited N. caninum proliferation by 97.8, 97.9, 85.3 and 46.4% in the range from 156 to 19.5 ng/ml. S. flavescens inhibited N. caninum proliferation by 98.6, 97.0, 69.5 and 14.0% in the range from 156 to 19.5 ng/ml. Toxicity to host cells was noted when concentrations of T. japonica and S. flavescens exceeded 625 ng/ml. The herb extracts from S. acutum, Pulsatilla koreana, and U. macrocarpa also showed toxicity at higher levels but did not achieve the same inhibition effects at the lower concentrations against T. gondii and N. caninum as T. japonica and S. flavescens.

Effect of ochratoxin A on Escherichia coli-challenged broiler chicks

A study was conducted to evaluate the effects of ochratoxin A (OA) on Escherichia coli-challenged broiler chickens. Day-old broiler chicks were separated into two groups of 92 chicks each, with one group fed a control mash diet, and the other fed a mash diet containing 2 ppm OA. On day 14, each group was further separated into two groups, with one group inoculated with E. coli O78 (1 x 10(7) colony-forming units/0.5 ml), whereas the other group was not inoculated with E. coli. After E. coli inoculation on day 14, four birds from each group were euthanatized at 1, 2, 3, 5, 7, 10, 14, and 21 days postinoculation. Escherichia coli infection caused dullness, depression, huddling, and diarrhea. Mortality was 14.3% in chicks infected with E. coli but fed no OA. Mortality increased to 35.7% in chicks fed OA and infected with E. coli. Decreased body weight and reduced feed intake were observed in chicks fed OA, and the effects were more pronounced in chicks fed OA and infected with E. coli. Increased serum levels of aspartate aminotransferase, alanine aminotransferase, uric acid, and creatinine and decreased levels of total proteins, albumin, globulins, calcium, and phosphorus were observed in OA-fed birds. Escherichia coli infection did not cause significant alteration in any of the serum biochemical parameters. The presence of OA in poultry rations increased mortality and the severity of an E. coli infection.

Reproductive toxicity of ergot alkaloids in mink

Ergot alkaloids are-synthesized by fungi of the Claviceps family that infect rye as well as other cereals and grains. Since a portion of the ranch mink diet is cereal, mink are at a risk of being exposed to ergot alkaloids. This study was performed to determine the reproductive toxicity of ergot alkaloids derived from ergot-contaminated oats in mink. Four groups of 12 female mink each were fed diets containing 0, 3, 6 or 12 ppm ergot alkaloids from 2w prior to the breeding season until the kits were approximately 33-d old (133 d). Females were mated with untreated males. Ergo talkaloids caused a transient decrease in feed consumption, but body weights were unaffected. The gestation period of the mink in the 6 ppm group was longer compared to controls. The number of mink whelping varied significantly with 9 mink whelping each in the control and 3 ppm groups compared to 4 mink in the 6 ppm group and 1 in the 12 ppm group. Ergot alkaloids had a significant effect on kit survivabilitywith no kits surviving in the 12 ppm group. Serum prolactin was significantly depressed in the 3 ergot alkaloid groups compared to the control group. This study indicated that ingestion of ergot alkaloids at 3 ppm or higher resulted in reproductive toxicity in mink.

Chronic effects of moniliformin in broiler and turkeys fed dietary treatments to market age

Floor pen studies were conducted, with broilers from 1 to 7 wk of age and with turkeys from 1 to 14 wk of age, to evaluate the chronic effects of moniliformin (M). Fusarium fujikuroi (M-1214) culture material was added to typical corn-soybean basal diets to supply 0, 25, or 50 mg M/kg diet (broilers) or 0, 12.5, 25, 37.5, or 50 mg M/kg diet (turkeys). Compared with controls, chicks fed diets containing 50 mg M/kg consumed more feed, had lower body weight gain, were less efficient in converting feed to body weight gain, and had increased relative heart and proventriculus weights. Chicks fed the diet containing 50 mg M/kg also had significantly higher mortality and decreased mean corpuscular volumes compared with controls. Broilers fed 25 and 50 mg M/kg also had increased serum gamma glutamyltransferase activities. Feed intake, body weight gain, and feed conversion of turkeys fed dietary M were not affected. At 6 and 14 wk, turkeys fed 25, 37.5, or 50 mg M/kg diet had increased (P < 0.05) relative heart weights when compared with controls. At week 14, turkeys fed diets containing 37.5 or 50 mg M/kg also had increased (P < 0.05) relative liver weights compared with turkeys fed 0, 12.5, or 25 mg M/kg diet. Lesions, observed only in the hearts of broilers and turkeys fed 50 mg M/kg, were loss of cardiomyocyte cross striations, increased cardiomyocyte nuclear size, and an increased number of cardiomyocyte mitotic figures (turkeys only). Results indicate that > or = 37.5 mg M/kg is hepatoxic and > or = 25 mg M/kg is cardiotoxic to turkeys and 50 mg M/kg diet is toxic to broilers fed to market age.

Use of a rat model to evaluate tall fescue seed infected with introduced strains of Neotyphodium coenophialum

Experimental cultivars of the pasture grass tall fescue are infected with unique strains of the fungal endophyte Neotyphodium coenophialum, which produce low concentrations of ergot alkaloids. A rat model was evaluated as a tool for rapid, initial screening of experimental cultivars considered to be nontoxic. Rats were fed diets that included seed from experimental cultivars of tall fescue with introduced strains of N. coenophialum and a toxic control diet containing seed of the cultivar Kentucky 31 (KY31), with its endemic strain of N. coenophialum. Rats were preconditioned to a nontoxic diet and then fed treatment diets for 13 days with 5 days at thermoneutrality (21 degrees C) followed by 8 days under heat stress (31 degrees C). For most of the 13-day treatment period, rats fed KY31 exhibited depressed daily intake compared to those fed diets of cultivars with introduced endophytes (P < 0.05). In addition, rats fed KY31 exhibited significantly less weight than rats on other diets after heat treatment was imposed. For all initial trials and repeated trials, total intake and total gain calculated at the end of each trial were the most consistent indicators of toxicity.

Chronic effects of fumonisin B1 in broilers and turkeys fed dietary treatments to market age

Floor pen studies were conducted with 270 broiler chicks and 144 turkey poults, all 1 wk old, to evaluate the chronic effects of fumonisin B1 (FB1). A completely randomized design was used in both studies with six pen replicates of 15 chicks or eight pen replicates of six poults assigned to each of three dietary treatments from Weeks 1 to 7 (broilers) or to Week 14 (turkeys). Fusarium moniliforme (M-1325) culture material was added to a typical corn-soybean basal diet to supply 0, 25, or 50 mg FB1/kg diet. Feed intake, body weight gain, and feed conversion of chicks were not affected (P > 0.05) by FB1. Turkeys fed 50 mg FB1/kg had significantly (P < 0.05) lower feed intake than the controls. Compared with controls, chicks and turkeys fed FB1 diets had significantly higher liver sphinganine to sphingosine ratios (P < 0.05). Relative organ weights of chicks were not affected (P > 0.05) by FB1, other than those chicks fed 25 mg FB1/kg, which had lower (P < 0.05) relative proventriculus weights than the chicks fed 0 or 50 mg FB1/kg. Broilers fed 50 mg FB1/kg had decreased serum calcium and increased serum chloride when compared to broilers fed 0 or 25 mg FB1/kg. Hematology was not affected (P > 0.05) by dietary FB1. No lesions were present in any organ examined microscopically. Results indicate that 50 mg FB1/kg diet is detrimental to turkeys but is not toxic to broilers fed to market age.

Toxicity of moniliformin from Fusarium fujikuroi culture material to growing barrows

In two studies, the effects of moniliformin (M)-contaminated diets from Fusarium fujikuroi culture material on growing barrows were evaluated. In the first study, six barrows (three replicates of two each, mean body weight = 17.8 kg) per group (four groups; 24 barrows total) were fed diets calculated to contain 0 mg M/kg feed (control); 25 mg M/kg feed; 50 mg M/kg feed; or 100 mg M/kg feed for 28 days. In the second study, the same experimental design and numbers of barrows (mean body weight = 15.3 kg) were used, and diets were formulated to contain 0 mg M/kg feed (control); 50 mg M/kg feed; 100 mg M/kg feed; or 200 mg M/kg feed. Diets of 100 mg or 200 mg M/kg feed reduced body weight, body weight gain, and feed consumption. Serum biochemical analytes were affected by 100 to 200 mg M/kg feed. Hematologic values were affected by 50, 100, and 200 mg M/kg feed. In the first study, one barrow in the 100 mg M-treated group died, and in the second study. one barrow died in the 100 mg M-treated group, and five barrows died in the 200 mg M-treated group. Relative heart weight was increased in the 200 mg M-treated barrows, yet tissues from organs collected from treatment groups were generally histologically unimpressive. The most consistent sign of M toxicity in barrows appeared to be death induced within 2 to 5 days by 100 to 200 mg M/kg feed.

Thermoregulatory ability of beef heifers following intake of endophyte-infected tall fescue during controlled heat challenge

Consumption of endophyte-infected tall fescue during summer months can result in severe hyperthermia in cattle. Six heifers (296+/-8.3 kg BW) were used to determine changes in body temperature control that occur with consumption of an endophyte-infected tall fescue diet during controlled heat challenge. All animals were exposed in five separate periods to a step increase in ambient temperature (Ta) from 21 to 31 degrees C while fed E+ (5 microg ergovaline x kg(-1) x d(-1)) or endophyte-free (E-) diets. Core body temperature (Tcore) was monitored continuously using implanted, telemetric temperature transmitters. Heat production and heat loss were also measured at selected times to identify primary effects of E+ on thermal balance. Pretreatment Tcore exhibited a diurnal rhythm at a constant Ta of 21 degrees C, with high and low values at 2300 and 1300, respectively. An increase in daily averaged Tcore (P < 0.001) occurred with an increase in Ta from 21 to 31 degrees C. Likewise, all phases of the daily cycle increased equally during this challenge. This increase at 31 degrees C was associated with higher levels of respiration rate, skin temperature, respiratory vaporization, and skin vaporization (P < 0.05) and lower blood levels of thyroxine (P < 0.05). Intake of the E+ diet further elevated Tcore in heifers during the short-term heat challenge (2 d), and the effect was most pronounced at 0000 to 0300 and declined thereafter. The increase in Tcore during E+ treatment was associated with an increase in respiration rate (P < 0.05), whereas metabolic heat production, skin temperature, skin vaporization and respiratory vaporization were unaffected. These results show that consumption of an E+ diet during continuous heat challenge results in a marked increase in core body temperature, especially during nighttime exposure to heat stress, due primarily to a reduction in cutaneous heat transfer, with no effect on heat production or other measured avenues of heat loss.

Prenatal fumonisin (FB1) treatment in rats results in minimal maternal or offspring toxicity

To investigate the neurobehavioral and developmental effects of the mycotoxin, FB1, Sprague-Dawley rats were treated with FB1 on gestational days 13-20. In Experiment 1, FB1 was obtained from culture material and pregnant rats were gavaged with 0, 0.8 or 1.6 mg/kg. In Experiment 2, pregnant rats were gavaged with purified FB1 at doses of 0, 1.6 or 9.6 mg/kg. Offspring were evaluated on a battery of behavioral tests as well as measures of whole and regional brain weight. There were no effects on maternal weight gain, reproductive outcomes, or offspring body weight through adulthood in either experiment. Complex maze performance, open field and running wheel activity were not altered by prenatal FB1 treatment. In Experiment 2, acoustic startle response was depressed at two ages during the first or second block of 9 trials in males treated with purified FB1. Females exhibited no such alterations. Play behavior at PND 33, but not PND 26, was increased in males prenatally treated with 9.6 mg/kg relative to those treated with 1.6 mg/kg. There were no substantive treatment effects on regional brain weight. These results suggest that doses of < or = 9.6 mg purified FB1/kg and/or < or = 1.6 mg FB1/kg obtained from culture material cause minimal maternal toxicity and produce few development functional alterations. In addition, potential FB1-related functional alterations were evident only in males providing further support for a mild sex-specific effect for fumonisin.

Occurrence of fumonisin B1 in maize and poultry feeds in Haryana, India

A total of 100 maize and 50 poultry feed samples collected in 1998 at random from nine and eight districts of Haryana, respectively, were analysed for fumonisin B1. The samples were collected from poultry farms, feed manufacturers and markets. Ninety one (91%) maize samples and forty two (84%) poultry feed samples were found to contain fumonisin B1. Fumonisin B1 contamination in the maize samples ranged from 0.1-87.0 ppm. Whereas the poultry feed samples contained fumonisin B1 in the range of 0.02-28.0 ppm. It indicated widespread prevalence of fumonisin B1 in maize and poultry feeds in different areas of Haryana.

Simultaneous determination of the predominant hyperforins and hypericins in St. John's Wort (Hypericum perforatum L.) by liquid chromatography

Hypericin and hyperforin are believed to be among the active constituents in common St. John's wort (Hypericum perforatum L.). Presently, dietary supplements are generally standardized to contain specified levels of hypericin and hyperforin, and the related compounds, pseudohypericin and adhyperforin. A rapid method was developed for simultaneous determination of these 4 active constituents by liquid chromatography (LC). A 1 g portion of dried, finely ground leaf/flower sample is extracted with 20 mL methanol for 2 h. A 0.6 mL aliquot of the crude extract is combined with 5.4 mL acetonitrile-methanol (9 + 1) and passed through a mixed solid-phase cleanup column. The eluate is examined by LC for hyperforin, adhyperforin, hypericin, and pseudohypericin on a Hypersil reversed-phase column by using simultaneous ultraviolet (284 nm) and fluorescence detection (excitation, 470 nm; emission, 590 nm). The compounds are easily separated isocratically within 8 min with a mobile phase of acetonitrile-aqueous 0.1 M triethylammonium acetate (8 + 2). Average recoveries of hyperforin and adhyperforin were 101.9 and 98.4%, respectively, for 3 sample mixtures containing concentrations ranging from approximately 0.2 to 1.5% combined hyperforins per gram dry weight. Average relative standard deviation (RSD) values for hyperforin and adhyperforin for all 3 mixtures were 18.9 and 18.0%, respectively. Average recoveries of hypericin and pseudohypericin were 88.6 and 93.3% respectively, from 3 sample mixtures containing concentrations ranging from approximately 0.2 to 0.4% combined hypericins per gram dry weight. Average RSD values for hypericin and pseudohypericin for all 3 mixtures were 3.8 and 4.2%, respectively.

The individual and combined effects of fumonisin B1 and moniliformin on performance and selected immune parameters in turkey poults

Effects of feeding diets containing fumonisin B1 (FB1) and moniliformin (M), singly or in combination, on performance and immune response were evaluated in poults. Day-old poults were randomly assigned to one of four dietary treatments with four replicates of four poults each. Dietary treatments were 1) control; 2) 200 mg FB1, 0 mg M/kg diet; 3) 0 mg FB1, 100 mg M/kg diet; and 4) 200 mg FB1, 100 mg M/kg diet. In Experiment 1, poults were injected with 0.25 mL Newcastle disease virus (NDV) vaccine on Weeks 2 and 3 of the experiment, and anti-NDV antibody titers were measured 7 d after each injection. Compared with controls, poults fed FB1 had significantly lower (P < 0.05) secondary antibody response. Poults fed M and the combination of FB1 and M had significantly lower (P < 0.05) primary and secondary antibody response. Lower relative thymus weights were observed in poults fed diets containing FB1 or M. Decreased relative bursa and spleen weights were observed in poults fed M. In Experiment 2, poults were placed on dietary treatments for 3 wk. On Day 21, 2 x 10(6) peripheral lymphocytes were incubated with mitogens. Poults fed diets containing FB1 had a significantly lower (P < 0.05) proliferative response to mitogens in comparison to controls. In Experiment 3, poults were placed on the diets for 3 wk and were injected with 4.4 x 10(7) E. coli/kg body weight on Day 21. Significantly higher (P < 0.05) numbers of E. coli colonies were observed in the blood and tissue homogenates of poults fed M. In all three experiments, feed intake and body weight gains were significantly lower (P < 0.05) in turkeys fed diets containing M. Data from the present study suggest that FB1 and M are immunosuppressive in poults and that M not only suppresses immune response but also performance. However, neither synergistic nor additive effects between FB1 and M were observed for any of the parameters measured.

Ingestion of fumonisin B1-containing culture material decreases cardiac contractility and mechanical efficiency in swine

Fumonisins are mycotoxins produced primarily by Fusarium verticillioides, a fungus that commonly contaminates corn. Fumonisin ingestion increases plasma and tissue sphingosine and sphinganine concentrations and causes porcine pulmonary edema, which has been attributed to acute left-sided heart failure or increased vascular permeability. We investigated the effect of short-term ingestion of fumonisin B1-containing culture material on cardiac function in pigs. Treated male pigs (n = 7) received fumonisin-containing culture material which was mixed into the grower diet at 20 mg fumonisin B1/kg body weight each day, while control pigs (n = 7) were fed only the grower diet on the same schedule as the treated pigs. Pigs were anesthetized after 3 days of receiving either diet and instrumented to accurately characterize the cardiovascular effects of fumonisin ingestion. Fumonisin-treated pigs had lower cardiac outputs and heart rates than control pigs. Fumonisin-treated pigs also had a marked reduction in cardiac contractility, as indicated by decreased values for end-systolic elastance (the gold standard in vivo measure of cardiac contractility), V(0) (the intercept value for the end-systolic pressure-volume relationship), and mechanical efficiency. These data indicate that in pigs, short-term ingestion of fumonisin B1-containing culture material produces negative inotropic and chronotropic effects and decreases mechanical efficiency of the left ventricle. Theses cardiovascular effects are consistent with fumonisin-induced, sphingosine-mediated l-type Ca(2+) channel blockade and suggest that pulmonary edema in pigs fed fumonisin is primarily due to acute left-sided heart failure instead of increased vascular permeability.

Effects of long-term feeding of diets containing moniliformin, supplied by Fusarium fujikuroi culture material, and fumonisin, supplied by Fusarium moniliforme culture material, to laying hens

Beginning at 24 wk of age, control diets or diets containing 50 or 100 mg/kg moniliformin (M), 100 or 200 mg/kg fumonisin B1 (FB1), or a combination of 50 mg M and 100 mg FB1/kg of diet were fed to White Leghorn laying hens for 420 d. The hens were then fed the control diet for an additional 60 d. At the beginning of the experiment, each treatment consisted of four replicates of six hens. Egg production was reduced by approximately 50% by the end of the second 28-d laying period and remained at approximately this level for the 420 d in only the hens fed the diet containing 100 mg M/kg feed. Production returned to control levels or above within 60 d after hens were fed the control diet. Egg weights were reduced by the 100-mg M diet during the first three 28-d laying periods before returning to weights comparable with controls. The hens in this group also had significantly lower body weights than the other treatments. Mortality was minimal except in hens fed the 100 mg M/kg diet and the 100 mg FB1/kg diet, on which approximately 20% of the hens died. The hens were artificially inseminated with semen from males fed control diets, and fertility was not affected by the dietary treatments. Importantly, toxic synergy between M and FB1 was not observed for any of the parameters measured. Results indicate that laying hens may be able to tolerate relatively high concentrations of M and FB1 for long periods of time without adversely affecting health and performance. Interestingly, hens fed the 100-mg M/kg diet were able to recover when returned to control diets. The likelihood of encountering M or FB1 at these concentrations in finished feed is small.