Leukocytic responses and intestinal mucin dynamics of broilers protected with Enterococcus faecium EF55 and challenged with Salmonella Enteritidis

The protective effect of Enterococcus faecium EF55 in chickens challenged with Salmonella enterica serovar Enteritidis phage type 4 (SE PT4) was assessed. The antibacterial effect on the bacterial microflora in the small intestine in relation to white blood cell count, phenotyping of peripheral blood and intestinal lymphocytes, functional activity of lymphocytes and phagocytes and mucin quantitation were investigated. Day-old chicks (85) were randomly divided into four groups. The probiotic group (EF) and Salmonella + probiotic group (EFSE) received E. faecium EF55 (10⁹ CFU – 3 g/group/day) for 21 days. The Salmonella group (SE) and EFSE group were infected with Salmonella Enteritidis (10⁸ CFU in 0.2 ml PBS) in a single dose per os on day four of the experiment. The control group chicks (C) were fed a commercial diet without added bacteria. Supplementation of EF55 in the diet of the chickens in the EFSE group, challenged with S. Enteritidis, caused the density of the intestinal mucin layer to increase significantly in non-specific regions (duodenum and jejunum), but decrease significantly in target regions (caeca) for S. Enteritidis. Probiotic treatment also appeared to result in a significantly higher number of lymphocytes in peripheral blood and a tendency to increase CD3, CD4, CD8, and IgM positive cells 3 days post-infection with S. Enteritidis. The results demonstrated an antibacterial effect and suggested that EF55 had a moderating effect on intestinal mucin production and leukocytic response in the early phase of S. Enteritidis infection.     

The community structure of arbuscular mycorrhizal fungi in roots of maize grown in a 50-year monoculture

We assessed the diversity of arbuscular mycorrhizal (AM) fungi colonizing maize roots grown in a long-term monoculture experiment established at Martonvásár, Hungary, 50 years ago to understand the effect of this extremely long monoculture on the community structure of these organisms. Mycorrhizal colonization of root samples was analyzed by PCR amplification and sequencing of partial ribosomal small subunit DNA fragments of fungal origin. Of the 257 sequences recovered, 203 belonged to Glomeromycota AM fungi. Phylogenetic analysis assigned the Glomeromycota sequences into 22 operational taxonomic units belonging to three families including Archaeosporaceae, Glomeraceae, and Paraglomeraceae. In agreement with previous reports, Glomus group A fungi dominated the arbuscular mycorrhizal fungi community of maize, but we found a relatively high richness of phylotypes within this group even after such an extreme and durable reduction of host plant diversity. Agricultural practices, including mineral fertilization and incorporating stalk residues, significantly affected the diversity within Glomus group A.     

Natural food evaluation and water quality in zero water exchange culture of Litopenaeus vannamei fertilized with wheat bran

The aim of this study was to analyze the influence of organic fertilizer on the availability of natural food (plankton and benthos) and water quality. Two fertilization protocols were adopted using inorganic and organic fertilizers with shrimp (stocked treatment) and their controls (unstocked treatment). Experimental units consisted of 12 circular fiberglass tanks (500 l) with estuarine sediment, individual aeration and no water exchange. In stocked treatments were used 40 juveniles/m², and they were fed with 35% crude protein marine shrimp ration, three times a day. Under the organic fertilization protocol, the plankton showed higher abundance of Nitzschia and rotifers, the phytobenthos consisted mainly of Nitzschia, Amphiprora and Oscillatoria, the epibenthos was represented mainly by nematodes and rotifers, and the macro-invertebrates were mainly oligochaetes. In relation to inorganic fertilization, the plankton was represented mainly by Coscinodiscus and rotifers, the phytobenthos consisted mainly of Amphiprora and Oscillatoria, the epibenthos was represented mainly by nematodes and rotifers, and the macro-invertebrates were mainly oligochaetes. Dissolved oxygen was higher for organic fertilizer (6.16 ± 0.98 mg/l) than for inorganic (5.92 ± 1.19 mg/l) while the other water quality parameters did not present significant differences. Survival was similar in the two fertilization regimes (96.6%). Final body weight was 11.89 ± 1.73 g for the inorganic fertilizers and 12.28 ± 1.71 g for organic fertilizer. It is concluded that wheat bran showed good performance in the water quality without exchange, in the availability of natural food, and in the growth and survival of the shrimps in the microcosms.     

Fusarium langsethiae and mycotoxin contamination in oat grain differed with growth stage at inoculation

European Journal of Plant Pathology - High levels of mycotoxins are occasionally observed in Norwegian oat grain lots. Mycotoxins of primary concern in Norwegian oats are deoxynivalenol (DON)...     

Phosphorus seed coating as starter fertilization for spring malting barley

Abstract

Experiments were conducted with malting barley (Hordeum vulgare L.) cultivars in 2003 and 2004 in central, western and southern Lithuania to test phosphorus (P) availability at early seedling growth stage with P seed coating. Phosphorus seed coating resulted in alteration to plant stand structure traits. Despite the fact that seedling emergence sometimes decreased, the number of total and productive stems, number of grains per ear and 1000-grain weight increased. The positive effect of P seed coating on grain yield was revealed when the growth conditions during post-anthesis were favourable for exploiting the potential that was obtained during the pre-anthesis phase. In our experiment favourable conditions were considered those that generated a grain yield over 6 t ha^?1. According to path coefficients analyses the significant positive effect of P seed coating on malting barley yield increase was related to seed weight increase. Although P seed coating slightly increased single grain N concentration and thus grain protein concentration, grain protein concentration ranged from 8.6% to 10.2% and met the quality standard requirements for malting barley in all trials and treatments.     

Toxigenicity and pathogenicity of <Emphasis Type="Italic">Fusarium poae</Emphasis> and <Emphasis Type="Italic">Fusarium avenaceum</Emphasis> on wheat

In a field experiment between 2004 and 2006, 14 winter wheat varieties were inoculated with either a mixture of three isolates of F. poae or a mixture of three isolates of F. avenaceum. In a subsequent climate chamber experiment, the wheat variety Apogee was inoculated with individual single conidium isolates derived from the original poly conidium isolates used in the field. Disease symptoms on wheat heads were visually assessed, and the yield as well as the fungal incidence on harvested grains (field only) was determined. Furthermore, grains were analysed using LC-MS/MS to determine the content of Fusarium mycotoxins. In samples from field and climate chamber experiments, 60 to 4,860 μg kg⁻¹ nivalenol and 2,400 to 17,000 μg kg⁻¹ moniliformin were detected in grains infected with F. poae and F. avenaceum, respectively. Overall, isolate mixtures and individual isolates of F. avenaceum proved to be more pathogenic than those of F. poae, leading to a higher disease level, yield reductions up to 25%, and greater toxin contamination. For F. poae, all variables except for yield were strongly influenced by variety (field) and by isolate (climate chamber). For F. avenaceum, variety had a strong effect on all variables, but isolate effects on visual disease were not reflected in toxin production. Correlations between visual symptoms, fungal incidence, and toxin accumulation in grains are discussed.     

Soil Solution Aluminum,and Nutrient and Aluminum Uptake in Hibiscus Sabdariffa Under Nitrogen and Phosphorous Fertilizers

The result of intensive agriculture in cities is the decline in crop yields and depletion of the resource base. The aims of this study were to assess effects of nitrogen (N) or phosphorus (P) fertilization on bioavailable aluminum (Al) and their contribution on Al and nutrient uptake in Hibiscus sabdariffa. A pot experiment was led to supply a tropical soil with N and P fertilizers. P amendment decreased Al in soil solution, not N amendment. Fertilizers had effects on Al and nutrient uptake in roots and leaves of Hibiscus sabdariffa. The results also showed that the uptake of Al and nutrients depends on Al in soil solution or N supply or P supply. Only P uptake in roots and leaves was explained by combined effects of a nutrient supply × exchangeable Al. Furthermore, P supply does not limit the translocation of Al in shoots of plants in acid soils.     

Spatial variability of fusarium head blight pathogens and associated mycotoxins in wheat crops

The spatial pattern of Fusarium‐infected kernels and their mycotoxin contamination was studied in four wheat fields in Germany using geo‐referenced sampling grids (12–15 × 20–30 m, 28–30 samples per field) at harvest. For each sample, frequency of Fusarium‐infected kernels and spectrum of species were assessed microbiologically; mycotoxin contents were determined by HPLC‐MS/MS analysis. Spatial variability of pathogens and mycotoxins was analysed using various parameters including Spatial Analysis by Distance IndicEs (sadie^® ). Microdochium majus, the most frequent head blight pathogen in 1998, was less frequent in 1999 and could not be detected in kernels from two fields in 2004. Fusarium avenaceum, F. graminearum and F. poae were the most frequent Fusarium species, with 7–8 species per field. The frequency of Fusarium‐infected kernels was 3–15% and the incidence of species showed considerable within‐field variability. Spatial patterns varied among Fusarium species as well as from field to field. Although pathogens and mycotoxin were often distributed randomly in the field, F. avenaceum, F. graminearum, F. poae, F. sporotrichioides, F. tricinctum and the mycotoxin moniliformin had an aggregated pattern in at least one field. Patterns are discussed in relation to spread of Fusarium species depending on inoculum sources, spore type, kind of dispersal, availability of susceptible host tissue and micro‐climate. Sampling of wheat fields for representative assessment of mycotoxins is complicated by random patterns of Fusarium‐infected kernels, especially where the frequency of infection is small.     

Development of qualitative and semiquantitative immunoassay-based rapid strip tests for the detection of T-2 toxin in wheat and oat

Novel qualitative as well as semiquantitative rapid strip tests for screening of T-2 mycotoxin in agricultural commodities were developed. Colloidal gold particles were coated with monoclonal anti-T-2 antibodies and used as detector reagent, indicating the strip test results by formation of up to two colored lines in a competitive assay format. The test line comprises a protein conjugate of the T-2 mycotoxin and the control line an antispecies-specific antibody to confirm the correct test development. To perform the test, 5 g of sample was extracted in a ratio of 1:5 with methanol/water (70:30) by shaking for 3 min and the extract directly used without further cleanup steps. The T-2 toxin lateral flow device (LFD) presented has a cutoff level around 100 microg/kg for naturally contaminated wheat and oat. The semiquantitative test may be used in the lower micrograms per kilogram range and allows for rapid semiquantitative photometric classification of the level of sample contamination. For both tests, results were obtained within 4 min. The developed LFDs therefore allow for the first time fast and on-site screening for the determination of T-2 toxin in cereals.