Stunted growth and mortality associated with sodium deficiency.

We investigated reports of stunted growth and high mortality occurring among young poultry in 38 small privately owned flocks in Vermont and New Hampshire. Tests for infectious agents including avian influenza and Newcastle disease viruses were negative, as were toxicologic tests for mycotoxins, heavy metals, pesticides, and monensin in feed samples. Analysis of 6 samples of implicated feed revealed 330-870 ppm of sodium (median level 350 ppm), whereas the recommended minimum level for chick feed is 1200-2000 ppm. A case-control study included 38 affected and 23 unaffected flocks. Statistical analysis showed that affected flocks were 29 times more likely to have consumed a particular brand of poultry feed (odds ratio = 29.2, 95% confidence interval = 3.2-675.8) but did not show any association between clinical signs and hatchery, location of chick purchase, chick purchase date, or years of producer experience.

Determination of total fumonisins in corn by competitive direct enzyme-linked immunosorbent assay: collaborative study.

Fumonisins-mycotoxins produced by some Fusarium species-have been shown to be the causative agent of diseases in horses and other domesticated animals as well as possible carcinogens in humans. A collaborative study was conducted to evaluate the effectiveness of a competitive direct enzyme-linked immunosorbent assay (CD-ELISA) for the determination of total fumonisins (B1, B2, and B3) in corn. The test portion was extracted with methanol-water (7 + 3), filtered, diluted, and tested on the CD-ELISA. Naturally and artificially contaminated corn test portions were sent to 13 collaborators in the United States. Naturally contaminated field test portions were prepared at 3 different levels. Artificially contaminated test portions were spiked at 1.0, 3.0, and 5.0 mg/kg total fumonisins (B1, B2, and B3). Average recoveries of total fumonisins were 120, 100, and 90%, respectively. The relative standard deviations for repeatability ranged from 13.3 to 23.3% and the relative standard deviations for reproducibility ranged from 15.8 to 30.3% across all levels tested. HORRAT values, calculated for each individual sample, ranged from 1.24 to 1.94. This method demonstrated acceptable intra- and interlaboratory precision at the levels tested.

Natural Occurrence of Fumonisins in Rice with Fusarium Sheath Rot Disease.

Twenty samples of rough rice (Oryza sativa) (unpolished kernels) collected during the 1995 harvest season from Arkansas (seven samples) and Texas (13 samples) were obtained from rice fields known to include plants with symptoms of Fusarium sheath rot putatively caused by Fusarium proliferatum. Samples were analyzed for fumonisin B1 (FB1) at three laboratories using three different extracting solvents by high-performance liquid chromatography (HPLC) or enzyme-linked immunosorbent assay (ELISA) methods. Forty percent of the samples were positive for FB1 at levels ≤4.3 µg/g by HPLC. The same samples contained FB1 at ≤3.6 µg/g when measured by an ELISA method. Most samples that were positive for FB1 were positive for fumonisin B2 (FB2) and fumonisin B3 (FB3) by HPLC at levels ≤1.2 µg/g. Very good agreement was obtained among the two laboratories using HPLC methods and the third using ELISA. Shelling of the unpolished rice results in hull and brown rice fractions. In a sample that contained 4.3 µg/g in whole kernels, the fumonisin level was very high in hulls (≤16.8 µg/g) and low in brown rice (≤0.9 µg/g). Milling of brown rice results in bran and white rice fractions. Fumonisins were found in bran at a level of ≤3.7 µg/g but were below the level of detection by HPLC in white rice. The presence of fumonisins (FB1, FB2, and FB3) was confirmed by fast atom bombardment/mass spectrometry. This is the first report of fumonisins in naturally contaminated rice in the United States.

Methods for Detection and Quantitation of Fumonisins in Corn, Cereal Products and Animal Excreta.

Fumonisins are a group of naturally occurring mycotoxins produced by strains of several different mating populations of Gibberella fujikori ( Fusarium section Liseola ). Fumonisins have been shown experimentally to be the causative agent of equine leukoencephalomalacia (ELEM), porcine pulmonary edema (PPE) syndrome, and to produce liver cancer in rats. Epidemiological evidence also indicates a possible correlation between the fumonisins and human esophageal cancer. The analytical method of choice for most samples has been high performance liquid chromatography (HPLC) using fluorescence detection. The present work describes the baseline resolution using an isocratic mobile phase of the o-phthalaldehyde (OPA) derivatives of fumonisin B1 (FB1), fumonisin B2 (FB2) and fumonisin B3 (FB3). The separation of the hydrolyzed forms of FB1, partially hydrolyzed FB1 (PHFB1) and fully hydrolyzed FB1 (HFB1) is also described. Results of analyses of com from 1992 crop year in both Iowa (mean = 0.05 µg/g, N = 80) and Pennsylvania (mean = 0.37 µg/g, N = 91) were significantly lower than mean levels reported for 1988, 1989, 1990 and 1991. Significant levels of FB1 were found in commercially prepared rat (2 µg/g) and horse (37 µg/g) feed. Levels of FB1, (0.05 to 1.2 µg/g) found in corn meal purchased from local groceries indicated a possible source of low level exposure of humans to fumonisins. The simultaneous isocratic separation of FB1, FB2, FB3 and the hydrolysis products of FB1, PHFB1 and HFB1from fecal samples indicated a possible difference in metabolism of FB1 in ruminants and nonruminants. In ruminants, the hydrolyzed forms of FB1 composed a significant (60 to 90%) portion of the total FB1 concentration found in the feces. In nonruminants, the parent compound, FB1, was the dominant (90%) species present. Both ruminants and nonruminants showed limited excretion of FB1 in their urine (<1 to 7% total FB1 in excreta).