Improve rumen microbiota robustness with a postbiotic of fungal fermentation
Solid-state fermentation (SSF) products produced by fermentation of plant substrates with fungi increase diet degradation, feed efficiency and animal performance. In addition, functional components of the postbiotic support the robustness of the microbiota. In dairy cow studies, SSF products demonstrated that degradation of organic matter and fibre are improved. Feeding SSF products also resulted in a greater milk yield.
The microbial fermentation in the rumen provides energy and protein to meet the requirements of the ruminant. The rumen microbiota is very diverse making it difficult to define its normal conditions. The concept of microbial community robustness describes the ability of a community to cope with disturbances and can be used as marker of a healthy microbiota. The robustness of the microbiota is greater with an increased diversity and complexity. Resistance, resilience and functional redundancy are factors affecting the microbial robustness and thus animal performance.
Solid-state fermentation (SSF) is the cultivation of microorganisms on moist solid substrates. Already thousands of years ago, SSF was used in food as a processing technology to ferment rice with fungi in order to make it more shelf stable and to increase its nutritional value. In animal nutrition, SSF can be used to upgrade the nutritive value of co-products or diets in general.
Figure 1 – Dried fungal fermentation products increase feed efficiency, microbial robustness and animal performance.
Depending on the substrates and fungi (e.g., Aspergillus spp., Neurospora spp. or Trichoderma spp.) used, a variety of enzymes can be produced by SSF, such as cellulases, xylanases, amylases, ligninases, inulinases, chitinases, and phytases. The broad spectrum of residual enzymatic activity leads to the degradation of different structures within the diet matrix resulting in an increased nutrient and energy digestibility, affecting rumen microbiota. The metabolites of the inactivated microbial cell components of this production process are part of the postbiotic effects of the SSF products (e.g., Maxfiber and Maxfiber/HSD), contributing to health benefits by strengthening microbial robustness in the rumen (Figure 1).
The efficacy of these type of products has been demonstrated in several trials. In one of the studies, Holstein Friesian cows were fed a control diet without SSF and a diet with SSF in a cross-over design of 5 weeks each. Results showed that feeding a SSF product resulted in a significant greater energy corrected milk yield (+2.3%). In another dairy cow study, the effect on apparent total tract digestibility and performance was assessed. Feeding SSF products resulted in a greater apparent total tract digestibility of organic matter, neutral and acid detergent fibre of up to 3.4%. The milk yield was 3.4% greater, and the milk short-chain fatty acid content increased by 3%. Results indicate that the SSF products improved organic matter digestibility by breaking up the diet matrix, thereby improving milk yield.
These effects were confirmed in a meta-analysis of 6 dairy cow field trials (ø140 cows/farm). The milk yield on all 6 farms was numerically greater for the SSF-supplemented treatment group (+5%) compared to the control. Furthermore, feed efficiency was numerically greater for the SSF treatment group than the control. This way, it was demonstrated that SSF products improve feed efficiency and performance in dairy cows (Figure 2).
Figure 2 – Milk yield and feed efficiency in dairy cows
In addition to the above performance parameters, postbiotic effects of SSF products were assessed in an in vitro study using human cells. Gene expression data showed that the SSF products have an anti-inflammatory effect, maintain cell barrier integrity and modulate energy metabolism. These latest findings are currently being assessed further in order to define the postbiotic effects in even more detail.In summary, postbiotics of fungal fermentation are able to increase the rumen efficiency by breaking up different structures within the diet, thereby not only improving animal performance but also contributing to a beneficial rumen microbiota.
All technical statements are based on scientific literature; references are available upon request.
