title: Occurrence of mycotoxins and yeasts and moulds identification in corn silages in tropical climate.
abstract: OBJECTIVE
  This study was aimed to identify yeasts and moulds as well as to detect mycotoxin in corn silages in southern Minas Gerais, Brazil.
  
  
  RESULTS
  Corn silages from 36 farms were sampled to analyse dry matter, crude protein, ether extract, ash, neutral detergent fibre, nonfibre carbohydrates and mycotoxins contents, yeasts and moulds population, pH and temperature values. The mycotoxins found in high frequency were aflatoxin in 77·7% of analysed samples, ochratoxin (33·3%) and zearalenone (22·2%). There was no significant correlation between the mycotoxin concentration and the presence of moulds. The pH was negatively correlated with ochratoxin concentration. Aspergillus fumigatus was identified in all silages that presented growth of moulds. Ten different yeast species were identified using the culture-dependent method: Candida diversa, Candida ethanolica, Candida rugosa, Issatchenkia orientalis, Kluyveromyces marxianus, Pichia manshurica, Pichia membranifaciens, Saccharomyces cerevisiae, Trichosporon asahii and Trichosporon japonicum. Another six different yeast species were identified using the culture-independent method.
  
  
  CONCLUSIONS
  A high mycotoxin contamination rate (91·6% of the analysed silages) was observed. The results indicated that conventional culturing and PCR-DGGE should be combined to optimally describe the microbiota associated with corn silage.
  
  
  CONCLUSIONS
  This study provides information about the corn silage fermentation dynamics and our findings are relevant to optimization of this silage fermentation.
authors.affiliation: Department of Animal Science, Federal University of Lavras, Lavras, Brazil.
authors.forename: B F
authors.initials: BF
authors.lastname: Carvalho
authors.affiliation: Department of Animal Science, Federal University of Lavras, Lavras, Brazil.
authors.forename: C L S
authors.initials: CL
authors.lastname: Ávila
authors.affiliation: Department of Biology, Federal University of Lavras, Lavras, Brazil.
authors.forename: P M
authors.initials: PM
authors.lastname: Krempser
authors.affiliation: Department of Food Science, Federal University of Lavras, Lavras, Brazil.
authors.forename: L R
authors.initials: LR
authors.lastname: Batista
authors.affiliation: Department of Animal Science, Federal University of Lavras, Lavras, Brazil.
authors.forename: M N
authors.initials: MN
authors.lastname: Pereira
authors.affiliation: Department of Biology, Federal University of Lavras, Lavras, Brazil.
authors.forename: R F
authors.initials: RF
authors.lastname: Schwan
mesh_terms: D001938:Brazil; D005285:Fermentation; D005658:Fungi / Q000145:classification / Q000254:growth & development / Q000302:isolation & purification* / Q000378:metabolism; D009183:Mycotoxins / Q000032:analysis* / Q000378:metabolism; D012820:Silage / Q000032:analysis* / Q000382:microbiology*; D014329:Tropical Climate; D015003:Yeasts / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification* / Q000378:metabolism; D003313:Zea mays / Q000737:chemistry / Q000382:microbiology*
chemical_list: D009183:Mycotoxins
keywords: PCR-DGGE; bunker silos; fermentation; mycotoxins; rep-PCR