Natural occurrence of mycotoxins in forage maize during crop growth in Japan: case study.

We investigated concentrations of mycotoxins during the growth of four cultivars of forage maize (Zea mays L.) in Nasushiobara, Tochigi prefecture, and their distribution in ears of maize grown in Morioka, Iwate prefecture, Japan. In experiment 1, we measured concentrations of naturally occurring fumonisin, nivalenol, deoxynivalenol and zearalenone at progressive crop growth stages. Concentrations of fumonisin in stems+leaves remained very low or not detectable, but those in ears became detectable at 40 days after heading and increased rapidly after 50 days after heading (DAH) (fumonisin B1+B2<3260 µg/kg; mean value at 50-74 days after heading). Concentrations varied widely within cultivars on the same day. Concentrations of nivalenol, deoxynivalenol and zearalenone in stems+leaves and in ears were low or not detectable throughout the experiment. In experiment 2, we collected three ears of each cultivar at the late yellow-ripe stage that showed extreme symptoms of Fusarium ear rot. Concentrations of fumonisin were extremely high in the upper half of ears in all cultivars (fumonisin B1+B2 18,000-25,900 µg/kg) but low in the lower half and bracts. Concentrations of nivalenol, deoxynivalenol and zearalenone were extremely low or not detectable. These results show that fumonisin concentrations in ears increased rapidly after 50 DAH, they were extremely high in ears of all cultivars with symptoms of Fusarium ear rot, and fumonisin was the most common contaminant. These results will help reduce mycotoxin contamination.

Effect of lactic acid bacteria inoculant and beet pulp addition on fermentation characteristics and in vitro ruminal digestion of vegetable residue silage.

The objective of this study was to determine the effect of beet pulp (BP) and lactic acid bacteria (LAB) on silage fermentation quality and in vitro ruminal dry matter (DM) digestion of vegetable residues, including white cabbage, Chinese cabbage, red cabbage, and lettuce. Silage was prepared using a small-scale fermentation system, and treatments were designed as control silage without additive or with BP (30% fresh matter basis), LAB inoculant Chikuso-1 (Lactobacillus plantarum, 5mg/kg, fresh matter basis), and BP+LAB. In vitro incubation was performed using rumen fluid mixed with McDougall's artificial saliva (at a ratio of 1:4, vol/vol) at 39°C for 6h to determine the ruminal fermentability of the vegetable residue silages. These vegetable residues contained high levels of crude protein (20.6-22.8% of DM) and moderate levels of neutral detergent fiber (22.7-33.6% of DM). In all silages, the pH sharply decreased and lactic acid increased, and the growth of bacilli, coliform bacteria, molds, and yeasts was inhibited by the low pH at the early stage of ensiling. The silage treated with BP or LAB had a lower pH and a higher lactic acid content than the control silage. After 6h of incubation, all silages had relatively high DM digestibility (38.6-44.9%); in particular, the LAB-inoculated silage had the highest DM digestibility and the lowest methane production. The vegetable residues had high nutritional content and high in vitro DM digestibility. Also, both the addition of a LAB inoculant and moisture adjustment with BP improved the fermentation quality of the vegetable residue silages. In addition, LAB increased DM digestibility and decreased ruminal methane production.

Immunomodulation in gut-associated lymphoid tissue of neonatal chicks by immunobiotic diets.

Developmental changes in immunocompetent cells of the gut during the first week posthatch were determined in broiler chicks fed immunobiotic lactic acid bacteria in the form of Lactobacillus jensenii TL2937-, Lactobacillus gasseri JCM1131(T)-, Lactobacillus delbrueckii ssp. bulgaricus NIAIB6-, or L. gasseri TL2919-supplemented diets. The relative weights of spleen and bursa of Fabricius in chicks fed the immunobiotic diets were slightly higher than the control valued at 1 and 3 d of age, with the exception of spleen weight in the L. gasseri JCM1131(T) at 3 d of age, the bursa of Fabricius weight in the L. gasseri JCM1131(T) at 1 and 3 d of age, and bursa of Fabricius weight in the L. gasseri TL2919 group at 1 d of age. There were no significant differences in body and liver weights among the treatments. When chicks were fed the L. jensenii TL2937- or L. gasseri TL2919-supplemented diets, expression of T cell-related mRNA [cluster of differentiation 3 (CD3), interleukin-2 (IL-2), and interferon-gamma (IFN-gamma)] in the foregut was significantly higher than that of control chicks at 3 or 7 d of age. Expression levels of toll-like receptor (TLR) mRNA tended to increase in the foregut of chicks fed the immunobiotic diets, except for the L. delbrueckii ssp. bulgaricus NIAIB6, compared with expression levels in control chicks. The Bu-1 mRNA expression levels in the bursa of Fabricius were not affected by the supplementations with immunobiotic lactic acid bacteria. These results show that immunobiotics, particularly L. gasseri TL2919, might be useful as immunomodulators to stimulate the gut-associated immune system in neonatal chicks, and thereby protect them from disease without decreasing growth performance as a possible substitution of antibiotics.

Immunostimulatory oligodeoxynucleotide containing TTTCGTTT motif from Lactobacillus rhamnosus GG DNA potentially suppresses OVA-specific IgE production in mice.

In a previous study of the immunoregulatory properties of commensal bacterial DNA, we identified the strong immunostimulatory oligodeoxynucleotide (ISS-ODN) ID35 in the genomic DNA of Lactobacillus rhamnosus GG (LGG). The observed effects of ID35 are because of the unique TTTCGTTT motif located at the 5' end of the ODN, which is different from the previously identified ISS motifs in humans and mice. In the present study, we used an ovalbumin (OVA)-sensitized mouse model to show that ID35 is a potent suppressor of antigen-specific immunoglobulin E (IgE) production in vivo. This effect was toll-like receptor 9-dependent, as GpC negID35 failed to suppress antigen-specific IgE production. ID35 activated the specific subset of CD11c+CD8a+ dendritic cells, which are associated with T-helper 1 (Th1)-type systemic responses, and effectively induced interferon-gamma (IFN-gamma) production by CD4+ T cells in OVA-challenged mice. These immunoregulatory effects of ID35 were comparable with those induced by the murine prototype ODN 1826. Thus, ID35 is the first ISS-ODN with such a strong immunostimulatory and IgE suppressor activity to be found in immunobiotic bacterial DNA.

Studies on the structure of a novel peptide antibiotic, K-582.

A novel peptide antibiotic, K-582, which exhibited significant growth inhibition of Candida, viruses and ascites tumor in mice, was found in the culture medium of a strain of Metarhizium anisopliae by Kondo et al. (J. Antibiotics 33, 535-542 (1980) ]. K-582 consisted of two components, designated K-582 A and K-582 B. Threonine, tyrosine, ornithine, and an unusual amino acid were common in both peptides, but lysine was an extra component of K-582 A. The unusual amino acid was identified to be threo-gamma-hydroxy-L-arginine (OHArg) by means of mass, nuclear magnetic resonance and infrared spectrometries of the derivatives and the related compounds. The threonine and the arginine were assigned to be L-configuration, and the ornithine and the tyrosine to be D-configuration in both K-582 A and K-582 B, and the lysine to be L-configuration by comparison of their optical rotatory dispersion spectra with those of standard amino acids. The elucidation of primary structure revealed that they were closely related heptapeptides with the following sequence: K-582 A:H-Arg-OHArg-Orn-Thr-Orn-Lys-Tyr-OH; K-582 B:H-Arg-OHArg-Orn-Thr-Orn-OHArg-Tyr-OH, and had the identical sequence in terms of the configuration of their constituents, namely L-L-D-L-D-L-D.