Aspergillus spp. isolated from the bovine gastrointestinal tract improve organic acid profiles in Urochloa decumbens fermentation

• Published in: Biocatalysis and agricultural biotechnology 2022-07, Vol.42, p.102360, Article 102360
• Main Authors: Abrão, Flávia Oliveira, Duarte, Eduardo Robson, Pessoa, Moisés Sena, dos Santos, Vera Lúcia, Gonçalves, Daniel Bonoto, Lima, Swiany Silveira, Simões Saliba, Eloísa de Oliveira, Rodriguez, Norberto Mário
• Format: Article
• Language: English
• Subjects: Aspergillus spp; In vitro fermentation; Organic acid; Ruminal microbiota; Tropical forage
• ISSN: 1878-8181; 1878-8181
• DOI: 10.1016/j.bcab.2022.102360

During the dry season, high productivity of cattle cannot be sustained through the supply of tropical forage alone, and microbial additives or probiotics represent potential alternatives to improve the performance of animals raised on pastures. In the present study, we evaluated organic acid profiles following the in vitro fermentation of Urochloa decumbens mediated by Aspergillus spp. isolated from the bovine digestive tract. Twenty fungal isolates were evaluated after 96 and 144 h of fermentation of U. decumbens hay (UDH) in saline solution, Sabouraud dextrose broth, or ruminal fluid. Following fermentation, organic acids in the culture media were detected using high-performance liquid chromatography. The production of major fermentation acids differed across fermentation times, fungal isolates, and culture media. Using UDH in saline solution as the sole substrate, gluconic acid was the major fermentation product of fungal isolates. Fermentation of UDH in Sabouraud dextrose broth produced butyric, citric, and propionic acids. Fermentation of UDH in ruminal fluid produced acetic, propionic, and butyric acids, with significant and positive correlations among their production. Five selected isolates increased propionate proportion relative to the control, indicating potential as additives or probiotics for ruminants receiving fiber-rich diets. [Display omitted] •Urochloa decumbens was fermented in three mediums by 20 Aspergillus spp. isolates.•Using NaCl solution, 19 isolates produced gluconic acid during the fermentations.•In fermentations with Sabouraud broth, 14 isolates produced citrate.•In fermentations with ruminal fluid, five isolates increased propionate proportion.