July 23, 2024

Selko research uncovers insights on inhibiting conidia growth and reproduction in animal feed

Selko, the feed additives brand of Nutreco, has uncovered insights that confirm the anti-fungal mode of action in a synergistic blend used in grain and animal feed preservation.

In experiments conducted at the Westerdijk Fungal Biodiversity Institute in the Netherlands, scientists isolated Aspergillus chevalieri from moulded feed originating from different continents and countries. Researchers used Aspergillus chevalieri, a xerophilic mould which grows under low water activity (aW), as a model to evaluate how the synergy between organic acids (Fylax with Actiprop^®) affected the mould's fungal survival structures, including the ability of mould spores (conidia) to germinate and grow.

 

Remarking on the significance of the research for animal feed production, Pedro Caramona, Category Lead (Feed Safety & Quality) at Selko, said,  "We have continuously strived to improve the precision of our models to be able to confirm the mode of action of ActiProp in actual field conditions. By further developing a statistically valid model, we can detail the mould's growth kinetics, cell metabolism, and development, providing a deeper understanding of the mode of action within the spore confirmed by electron microscopy imagery."

 

A scientific paper expanding on this work will be published in the International Journal of Food Microbiology later this year.

 

The anti-fungal properties of propionic acid have long been used as a preservation step in grain and animal feed production. However, the application of a single acid may not be as economically viable as perceived. Propionic acid is quite volatile, and its long-lasting effect can be compromised. Buffering with an ammonium agent supports a more effective application, reducing its corrosive proprieties and supporting safer handling.

 

Westerdijk Fungal Biodiversity Feed Institute, home to the world's most diverse fungal collection, together with scientists from Selko, conducted a series of experiments that looked at how a combination of ingredients in an anti-fungal blend (Selko's Fylax Forte HC with ActiProp technology) affected germinating conidia, and subsequent germ tubes and hyphae. Light microscopy was used to count the colonies that developed. Fungal colonies from isolated conidia germination and growth were accessed for the different treatments using the oCelloscope™.

 

Results showed that the survival and development of Aspergillus chevalieri conidia was significantly decreased in the presence of Fylax with ActiProp, compared to a control group. The anti-fungal blend was demonstrated to significantly reduce the ability of hyphae (fungal cells) to grow compared to a control group (Table 1).

 

 

Table 1. Germination efficiency of conidia of Aspergillus chevalieri after incubation in demi water and different components for 48 h at 25C in MEA20S media.

  

Fluorescence live-dead staining conducted on hyphae showed the percentage of cells that were significantly stained after cells were exposed to the feed additive blend at two different concentrations, and a control group. Significantly more cells were damaged after incubation with the blend at both concentrations compared to the control (Table 2).

Table 2: % Damage cells stained with TOTO-1 after 30 min. incubation.

  

Actiprop interferes with critical processes involved in energy production and ATP synthesis.

The electron microscopical imagery of untreated and treaded conidia reveals the active ingredient's ability to affect the cell membrane integrity and exert a disrupting effect particularly on the mitochondria, inhibiting spore germination, growth, and preventing spores to germinate.

"The ability to isolate conidia in animal feed, study its metabolism kinetics, reflects the commitment to innovation Selko is bringing to further science, and understand the effectiveness of our solutions on grains and feed preservation in support of a safer feed to food chain," said Caramona.

 

- Selko