Lactic bacteria have become key players in the current scientific and nutritional reality, so much so that they keep arousing increasing interest in basic and applied research fields and in the evolution of biotechnological processes of animal food preparation.

The possibility of conserving plants throughout the ensiling process has been known for centuries all over the world. However, not always the results match expectations, because – as all the processes that depend on the natural microflora activity – they are subjected to many variables.



Even if the aerobic microorganisms number much more in fresh forage, they are rapidly replaced by microorganisms that develop in the absence of oxygen (anaerobic microorganisms) in silage. Success and failure of silage are determined in the first hours of conservation. In this phase, depending on the type of microorganisms that manage to colonize the substrate and dominate the others, the silage quality changes. In normal physical, chemical and biological conditions, the main role is played by lactic bacteria that, in 48 hours, can increase by hundreds of thousands of times. This quick and intense development is possible when the residue in the silage is low, when the temperature is between 25-30 °C, when the plant juice buffering capacity is low, and when there are no compounds with antibacterial action in the substrate.

The lactic bacteria that manage to develop in an ensiled silage have obligated or facultative heterofermentative metabolism.

The facultative heterofermentative bacteria are:

Bacilli: Lactobacillus plantarum, Lactobacillus casei, Lactobacillus curvatus, Lactobacillus coryniformis;

Cocci: Pediococcus pentosaceus, Pediococcus acidilactici, Streptococcus faecium.

This association of strains is able to best meet the current needs.

The obligated heterofermentative bacteria are:

Bacilli: Lactobacillus brevis, Lactobacillus buchneri, Lactobacillus fermentum;

Cocci: Leuconostoc mesenteroides, Leuconostoc paramesenterroides (they must not be included since they perform an ineffective fermentation pathways).


A pivotal step for the development of our knowledge has been the research of strains with complementary characteristics and with a mixture whose ratio would satisfy the widest possible range of physical-chemical conditions. Among the lactic bacteria, the species that more easily manage to colonize and reach high numerical values (109/g) in a fresh silage is L. plantarum. This species has proved its genetic stability for functional properties that determine metabolic and antagonistic activities and its connection with the natural habitat. Therefore, this type of bacterium turns out to be more suitable for ensiling thanks to its acidifying properties and the fact that it does not cause energy and dry matter losses. Whereas, the obligated heterofermentative bacteria lower pH on a smaller case, with a consequent loss of dry matter because of the release of CO2. In the unavoidable competition that arises inside the silage normal microflora during the ensiling process, the microflora total acidifying power is extremely important, but what is even more important is the acidification speed. The availability of rapidly fermentable sugars for lactic bacteria is largely due to the activity of plant enzymes that quickly hydrolyze the complex carbohydrates into their monomers. The facultative heterofermentative bacteria final products vary depending on the kind of available carbohydrates; in fact, it is known that – starting from the arabinose or the xylose – they produce lactic acid and acetic acid. These measures allow reducing the duration of the aerobic phase to a minimum and to actively control the proliferation of clostridia, yeasts and molds. i.e. microbial groups involved in the product qualitative depletion processes. The use of L. plantarum strains unlocks the door to the possibility of obtaining a silage that – besides conserving its nutritional prerogatives during the ensiling process – is not significantly affected by the unavoidable exposure to air during the silage unloading process. But let’s not forget that the ensiling process success is extremely variable and can be influenced also by other factors, such as: season and climatic conditions at harvest time, silage cutting and transporting methods, presence of decomposing materials in soil, shredding, drying level, etc. If the plant is not harvested at the correct level of ripeness (for external circumstances), Akron S.r.l. researchers propose to resort to the use of carbohydrates sources together with starters for silages, such as PERFECT SIL, enriched with enzymes that facilitate the monomer release.


  • Are addictivesa composed of live microorganisms (not less than 109 /g) that arrive alive on the silage;
  • Are able to get the most out of the substrate to externalize all its biological abilities;
  • Are strain mixtures with complementary attitudes;
  • Have the ability to actively ferment the typical sugars of plants;
  • Have a good competitive ability;
  • Are genetically and physiologically stable;
  • Are able to produce essential amino acids;
  •  Increase the quantity of produced acids;
  • Are able to prevent the development of molds and clostridia;
  • Are able to start a fermentation process in which unwanted microorganisms are rapidly inhibited;
  • Have a “marker” for their identification and protection.