Fusarium species and moniliformin occurrence in sorghum grains used as ingredient for animal feed in Argentina

PENA GABRIELA; VERONICA FUMERO; CAVAGLIERI LILIA; CHULZE SOFIA

Congreso; International Commission on Food Mycology. Workshop 2016; 2016

Sorghum (Sorghum bicolour L) is the fourth most important summer crop in Argentina after soybean, corn and sunflower. In our country, its importance lies in the use of grains and fodder as a supplement for animal feed. Argentina ranks second as sorghum exporter in the world. Fusarium species usually associate with sorghum belong to Fusarium fijikuroi species complex and can produce mycotoxins that are harmful to both humans and animals. The aims of this study were to determine Fusarium species and the moniliformin (MON) contamination in 48 sorghum grain samples collected from two fields located in Córdoba, Argentina. The Fusarium species were isolated on Nash Snyder medium. A total of 688 Fusarium strains were randomly taken and transferred to SNA agar. After single-spore culturing, 201 isolates were identified to species level by morphological characteristics on carnation leaf agar (CLA) and potato dextrose agar (PDA). Translation elongation factor- 1 alpha (EF-1α) gene was amplified in selected strains showing morphological characteristics of F. verticillioides. Moniliformin was detected by UV HPLC coupled to SPE column clean up. All samples showed Fusarium contamination with infection levels ranging from 82.5 to 99%. Among the Fusarium fijikuroi species complex identified, F. verticillioides was the most frequently recovered (46.4%) followed by F. proliferatum (13.9%) and F. subglutinans (8.2%). Based on the EF-1α gene sequences the strains were F. thapsinum and F. andiyazi. Fusarium graminearum species complex also was isolated in a high frequency (26.3%). Other Fusarium species identified were: F. semitectum, F. oxysporum and F. sporotrichioides; although they were rarely isolated. Natural occurrence of MON was detected. The toxin levels found ranged from 363.2 to 914.2 ng/g (mean value: 605.06 ng/g).