Digestibility & Commercial Pet Food

Digestibility & Commercial Pet Food

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Press surrounding the safety and accessibility of healthful raw meat-based diets for pets is often loaded with controversy. I spend a good portion of my job here at Primal helping to educate veterinary professionals on why more and more consumers are trying raw diets for their pets. I’m most often asked first about food safety. Concerns about feeding raw meat to a pet that also sleeps in the toddler’s bed or sits on grandma’s lap are at top of mind for my well-intended veterinary colleagues. Once I’ve made it clear to them that safety is a priority here at Primal Pet Foods, the conversation quickly moves toward balance. How are we sure that our foods are complete & balanced, containing all the nutrients essential for puppies to seniors? 

Just because we are an independent raw pet food company doesn’t mean that we are not interested in product research and science-based nutritional information. We’ve been committed to producing complete and balanced frozen raw foods since 2001. We test our diets post formulation at a 3rd party laboratory to be sure we’re meeting the AAFCO guidelines. We also completed all life stage feeding trials in 2012 for canine and feline formulas. In 2019, we added some digestibility testing to confirm what we believed to be true about our whole-food-based diets and while I’m excited to share our findings with my veterinary colleagues, I’d also like to share the results with all of you.

So, what is digestibility anyway?

The digestibility of a pet food is referring to the percentage of the food or nutrient that is completely digested, used, or absorbed by the animal. If you’re talking about calories you’d say, “the dog ate 1000 calories of food and 100 calories were found in the dog’s stool, so the caloric digestibility of the food given was 90%”.

Why should we care?

Simple answer: The more digestible a food, the less poop in the yard or litter box!

Complicated answer: The less digestible a food is, the greater the chance of your pet missing out on necessary nutrients. A macronutrient, like protein, left undigested can mean less amino acids are absorbed.  Studies also show that when there is a large amount of undigested fiber, micronutrients can be blocked from absorption by the sheer volume of undigested food that reaches the lower digestive tract, physically blocking them from being picked up.

Each nutrient has its own digestibility or bioavailability sweet spot, some are more digestible than others based on many factors. Pet food companies should be sure that each nutrient they’re providing is available for the pets eating it. An example that I often refer to is printed in the AAFCO official publication (2019 p. 154-155). The publication states that if we are meeting their published minimum protein and amino acid requirements for puppy growth then the crude protein digestibility of the food is expected to be at least 80% in order to ensure these are met.

So, why don’t we see digestibility published on pet food labels or discussed by manufacturers?

An independent study published in 2014 in the Journal of Nutritional Science evaluated 8 commercial kibble dog foods for digestibility. The results in that study highlight the need for more transparency in pet food labeling as foods with similar labeling of ingredients and guaranteed analyses had different digestibility and therefor did not offer equivalent nutritional benefit. There have been a few studies showing the high digestibility of raw & gently cooked diets in dogs and cats including this newer one from The Journal of Animal Science.

At Primal we’ve always believed in the power of whole food nutrition and we know that by carefully curating and minimally processing we can deliver nutrients to your pets without the use of a synthetic vitamin pack. In the spirit of transparency, we sent our formulas to a 3rd party laboratory for a controlled, AAFCO-method study of digestibility to compare our non HPP frozen (Canine Lamb Formula), HPP frozen (Canine Chicken Formula), and freeze dried HPP (Canine Chicken Freeze Dried Formula) diets.

Although anecdotally we don’t see a difference in our pets’ stool when they switch between frozen and freeze dried versions of our foods or between HPP and non HPP versions of our foods, we thought it would be a good idea, especially in light of the FDA’s DCM investigation, to compare these differing processing steps to ensure that all Primal recipes are meeting the high standards we set for ourselves.

Let's compare what we found at the lab regarding Primal digestibility versus the results of the published study data I referred to above: 

Primal digest study docs: Freeze-Dried Chicken, Frozen Chicken, Frozen Lamb
*Kibble digest data found by column reported in Table 1 here
**Extruded, Raw & Cooked digest data from industry sponsored published study

Great news for Primal pet parents is that neither our gentle HPP nor our freeze-drying process is impacting the high digestibility of our foods. The average protein and caloric digestibility of 94%, regardless of preservation or safety-insurance steps, means that you can feel confident that every Primal recipe you choose is fueling your pet with the protein, calories and nutrients he or she needs. We know that many of our customers feed a kibble base, and that’s ok! Just remember that on average 20% of that bag is going right to your pooper scooper. It should be clear from the chart, that any small amount of raw that you can add to your pet’s bowl will be beneficial for their digestion and overall health. Some fresh is better than no fresh.

One of my academic heroes Albert Einstein said, “Once you stop learning, you start dying.” We promise, at Primal Pet Foods, to never stop learning, evolving and researching in order to stay true to our company philosophy of providing the absolute best in whole food nutrition to you and your pets.