First, to fully appreciate the benefits that mushrooms might offer your pet, let's define how mushrooms differ from other fungi...

Mushrooms are part of a special group of fungi that form a fleshy, above-ground reproductive structure called the "mushroom fruit body" – that’s the part we love to eat.

In contrast, fungi that are not mushrooms do not form fleshy fruit bodies.

However, the "mushroom fruit body," or the part that you can see – the stem and cap – is less than 10% of a mushroom's total biomass.

The mycelium is the part of the mushroom you don't typically see or eat. It lies beneath the surface of the soil and…

It's the part that may hold the most important nutritional benefits of mushrooms.

Mycelium is a vast network of living cells covering much of the earth's surface. The largest biological entities on the planet, these "fungal mats" can live for decades and even centuries.

In fact, one of these gigantic mycelium "mats" currently covers over 2200 acres in a forest in Oregon.

Mycelium is essential to a healthy forest's ecosystem – it's what nourishes and replenishes the soil.

And the job isn't always easy... Mycelium cells are constantly battling against hostile environments. To aid their survival, mushrooms have developed highly efficient and proactive immune systems.

Many scientists believe that these protective capabilities that have evolved over the years – the mycelia's highly adept immune system – along with its ability to break down natural organic matter, are exactly what make mushrooms so valuable to mammals.

When you’re looking for an ideal supplement for your pet, it’s important to know that quality varies widely.

Here are five questions to ask about any mushroom product you’re considering for your cat or dog:

1. What's the ratio of fruit body to mycelium?
2. Is it produced using solid-state fermentation or "submerged fermentation"?
3. Does it contain mushroom isolates or whole-food mushrooms?
4. What type of grain is used for the fermentation process?
5. Are the mushrooms organically or conventionally grown?

Some of the potential answers to these questions might surprise you...

1. Fruit Body or Mycelium – Which Is Preferable?

Mushroom expert Steve Farrar of M2 has over 30 years of experience growing mushrooms. He recommends choosing products that contain more of the mycelium. His reasons?

• There is more research on the mycelial stage of the mushroom, by far than the fruit body stage.
• The mycelial stage of the mushroom is easier to standardise and keep contained.
• Mushrooms are grown to the fruit body stage for harvesting risk environmental factors that can be more difficult to control, so there's more variation in the quality.
• Mushroom fruit bodies attract airborne contaminants, both biological and industrial, so there's a greater risk for contamination.

2. Whole Food vs. Mushroom Extract Isolates: What's the Difference?

There are two primary types of mushroom supplements:

• Mushroom concentrate extracts

  This is the type you commonly find on store shelves and online. Many are "hot water extracts," which means the mycelia or fruit body is boiled for extended periods to extract and concentrate the beta-glucans, but you typically lose the enzymes, protein, fibre and most of the antioxidants.

• Whole food mushrooms

  With whole-food mushrooms, you get the benefits of enzymes, antioxidants, fibre, protein, co-enzymes and other important co-factors responsible for the nutrients' actions. The whole food form offers your pet diverse support for various systems instead of just beta-glucans.

Just as eating a fresh vegetable with its fibre and natural nutrients intact is the preferred way to get those nutrients, the same is true with mushrooms.

When you extract certain bioactive compounds from mushrooms, such as beta-glucans and polysaccharides, you leave behind the enzymes, coenzymes and chelated mineral activators. These valuable compounds support the mushrooms' bioactivity and the way in which your pet's body may receive benefits from the compound. The extraction process can also damage many of the bioactive enzymes and proteins.

And here's something else to consider... Highly concentrated mushroom extracts can potentially bring unintended consequences. As powerful as they have the potential to be, an overload of certain compounds in isolated extracts may shut down the important feedback your pet's body depends upon.

3. The Mycelium's Substrate – Why Bark & Whiskers’ Supplier Chose Oats Over Rice

Mushrooms in the wild are typically found growing in places such as on dead trees or on forest floors covered by decaying leaves.

When mushrooms are grown on a commercial scale, the producer has to choose a substrate to recreate that environment.

One popular commercial substrate is hulled brown rice. However, Bark & Whiskers’ supplier believes oats make a better-growing substrate than rice.

There are several reasons:

• The outer hull protects the oat seed from oxidising and turning rancid.
• Oats' cellulose, hemicellulose, and lignin stimulate the mushroom to activate a more complete set of metabolic and enzymatic pathways, vital to the mycelia's bioactivity.
• Oats are easy for the mycelium to digest.
• Oats' plant beta-glucans complement the fungal beta-glucans.

Unlike many other mushroom products, the mycelium for Bark & Whiskers™ Organic Fermented Mushroom Blend is cultivated using 100% organic Whole Oats, complete with the outer hull intact.

4. How M2's Proprietary Solid-State Fermentation Method Raises the Bar on Quality

M2 has developed a proprietary Solid State Fermentation (SSF) method to produce their mushrooms.

In the SSF process, the insoluble substrate – in this case, organic whole oats – is fermented with just the right amount of moisture. It results in higher quality production and yields while degrading the starch and enhancing the resulting nutrients.

As part of this process, the oats are cooked to hydrate them to 55% moisture and to help remove competing fungi, viruses, yeast and bacteria.

This substrate is now ready for the mycelium starter to be added.

At this point – and right before the biomass enters the erupting fruit body stage – the bags are opened and the biomass is slowly dehydrated to reduce the moisture content. The use of a controlled, low 118 degrees preserves live enzymes, protein structure and the many bioactivities of each mushroom species.

Grown in bags over the next 30 to 80 days, the mycelium gradually digests the oats until the grains vanish, leaving behind a solid white mass – the mycelium biomass. Due to this length of time, almost all the oats are digested, unlike mushroom spawn, which is harvested after about seven days.

Once the mushroom biomass reaches 5% moisture, it is milled into a fine powder and is ready for use.

For a more comprehensive beneficial effect from a mushroom supplement, look for a product using "Solid-State Fermentation." SSF uses a whole-food approach that yields a product containing more or most of the original compounds and co-factors.

5. 100% Grown and Processed in the U.S.

With mushrooms, the growing environment matters, just as it does with other plants. Their intense ability to concentrate both minerals and metals in their tissues makes polluted environments a real threat to their purity… and to the animals consuming them.

When grown in a polluted environment, mushrooms can concentrate heavy metals, which can be toxic, depending on the levels.

Recently, Asian (and Chinese, in particular) mushroom products have been found to contain unhealthy levels of lead, cadmium, arsenic and chromium, most likely from widespread water, soil and air pollution.

Although M2 mycologists select strains of mushrooms from around the globe and carry home tissue cultures of these extraordinary species, they propagate and produce all of their own mushroom mycelia in their lab in San Marcos, California.

All critical points of quality control stay totally in their hands.

Further, they routinely test for toxic heavy metals in the tissue samples, the organic oat substrate and the finished mushroom ingredients, to ensure that there are no unhealthy levels of heavy metals.

Two biologically active compounds in the mushroom fruit bodies and mycelia top the list… beta-glucans and proteoglycans.

Beta-glucans are chains of polysaccharides, and proteoglycans are special proteins, often found in connective tissue. What makes mushroom-derived beta-glucans so unique in supporting health is their ability to support optimal immune function without overstimulating the immune system.

The beta-glucans found in mushrooms are large and complex long-chain molecules. What sets certain beta-glucans apart are their unique side-branching patterns. Side-branching is one of the features that gives beta-glucans its immune-modulating ability.

Other bioactive compounds in mushrooms may also provide immune support for your pet.

While beta-glucans have been the most studied component of mushrooms and their mycelium, these amazing fungi also contain other bioactive compounds and proteins, including:

• Alpha-glucans
• Antioxidants
• Enzymes
• Pectins
• Ribonucleases
• Ubiquitin-like proteins
• Peptides
• Lectins

These beneficial substances help your pets by aiding their digestion, supporting cellular health and fighting free radicals in their bodies.

Did you know your pets' GI tracts are their largest immune barrier?

When their gut lining is healthy, it provides a barrier through which only the nutrients from digestion can pass, while keeping out pathogens and undigested particles.

So, when you take measures to fully support your pets' immune system, it's important to pay attention to their digestion and gut health too.

Mushrooms and their mycelium’s complex matrix of nutrients, dietary fibre, and fungal enzymes have been shown to support healthy digestion and gastrointestinal tract function.

The important enzymes produced by mushrooms include:

• Protease – helps digest proteins and, through its actions, helps cleanse your pet's bloodstream of excess undigested protein.
• Lipase – helps digest fat.
• Amylase – helps break down starch into sugar and supplies your pet's body with energy.
• Cellulase – helps break down fibre, which in turn promotes bowel health and regularity.

These digestive enzymes – that are part of the mushroom itself – are even capable of surviving the stomach's harsh, acidic conditions.