FUNGAL AND MICOTOXIN CONTAMINATION IN MIXED FEEDS: EVALUATING RISK IN CATTLE INTENSIVE REARING OPERATIONS (FEEDLOTS)

Argentina is the fourth global beef producer. Exposure to mycotoxins through contaminated feed is a major hazard for ruminants. In the present study we assess mycobiota, aflatoxin B1 (AFB1), fumonisin B1 (FB1), deoxynivalenol (DON) and zearalenone (ZEA) levels in total mixed rations (TMRs) during two consecutive years. Total fungal counts were evaluated and fungal species were identified. Also, ability of A. flavus isolates to produce AFB1 in vitro was tested. Natural contamination with AFB1 and FB1 was quantified by HPLC. Deoxynivalenol and zearalenone were analysed by immunochromatography and thinlayer chromatogra- phy (TLC), respectively. Fungal counts varied from not detectable (ND) to 2.10 x 108 CFU g-1. The prevalent genera were Aspergillus spp (60 %) and Fusarium spp (66.7 %), respectively The prevalent species was Aspergillus fumigatus. 50 % of A. flavus strains produced 75 to 112.5 μg g-1 AFB1. 46 % of 2007 samples were contaminated with 4 to 10 μg kg-1 AFB1. Deoxynivalenol was detected in 33.3 % of the samples (≥ 1. 25 μg g-1). Fumonisin B1 and ZEA were not detected. This study can be useful to estimate the mycotoxicological risk of cattle TMRs in this region and to compare results with studies from other beef-producing countries

Effects of polyphenols and lipids from Pennisetum glaucum grains on T-cell activation: modulation of Ca2+ and ERK1/ERK2 signaling

International audienceBACKGROUND: Pearl millet (PM), i.e., Pennisetum glaucum, is widely grown in Africa and known for its anti-oxidant and anti-hyperlipidemic properties.METHODS: The P. glaucum grains were obtained from the region of Ouled Aïssa (South of Algeria). We assessed the effects of phenolic compounds and lipids, extracted from seeds of P. glaucum, on rat lymphocyte proliferation, activated by phorbol 12-myristate 13-acetate and ionomycin. In order to explore signaling pathway, triggered by these compounds, we assessed interleukin-2 (IL-2) mRNA expression and extracellular signal-regulated kinase-1/2 (ERK1/ERK2) phosphorylation. Finally, we determined increases in free intracellular Ca(2+) concentrations, [Ca(2+)]i, by employing Fura-2/AM in rat lymphocytes.RESULTS: The composition of P. glaucum grains in polyphenols was estimated to be 1660 µg gallic acid equivalents (GAE)/g. Lipids represented 4.5 %, and more than 72% of the fatty acids belonged to unsaturated family. Our investigation showed that both lipid and phenolic compounds inhibited mitogen-induced T-cell proliferation. Compared with phenolic compounds, lipids exerted weaker effects on ERK-1/ERK2 phosphorylation and Ca(2+) signaling in mitogen-activated T-cells.CONCLUSION: We conclude that the immunomodulatory effects of P. glaucum could be contributed by its phenolic and lipid contents