Digestibility: The Proof Is in The POO-dding
When our dog, Archer, first started on a raw diet, his poop immediately shrank in size.
This is a common observation among owners who choose to feed raw and/or lightly cooked meals that are rich in animal protein and low in carbohydrates.
Even though Archer was eating more in weight, his out-poop was considerably lesser, firmer and less stinky.
Why does out-poop matter?
Poop size and quality (i.e. soft, smelly or slimy) is largely determined by how digestible a diet is.
Digestibility reflects how effective essential nutrients in food are actually absorbed by the body during digestion.
If a dog eats 800g per day and produces 150g of poop per day, he is absorbing 640g of his diet effectively into his body which makes his diet roughly 80% digestible.
The more digestible a diet, the easier it is for our companion to break down the diet and absorb it’s nutrients.
Let's compare two different bags of pet food with similar nutrient percentages (Fat, Protein, Moisture, etc.). Brand A and B both provide 30g of protein for every 100g of food.
When fed 100g of Brand A, the cat/dog expels 5g of protein through its poop.
When fed 100g Brand B, the cat/dog expels 10g of protein through its poop.
This would mean Brand A provides 25g of digestible protein per 100g whereas Brand B only provide 20g of digestible protein.
Both food might have 30% protein content, but the bag that has good digestibility would provide more nutrient per scoop as compared to the bag with poor digestibility.
Although it is possible to “replace” the nutrients lost through poor digestibility by feeding more, it would not be ideal both financially or for overall health. Feeding large amounts of food is not only more costly but also stresses the digestive system. Organs will be under added pressure to produce digestive enzymes to cope with the influx of food.
While high digestibility is good, food should NOT be a 100% digestible. It is normal for the body to produce poop. Indigestible material like fiber, passes through the body doing a clean up along the colon. Without sufficient fiber, your companion might suffer from constipation and diarrhea. Thus, indigestible foods are not automatically bad.
Factors that affect digestibility include but are not limited to
1. Biological value, 2. Species appropriateness, 3. Manufacturing process and 4. Quality of ingredient.
Biological value or BV for short is the measure of usable amino acids in a protein.
A high BV reflects a large amount of usable amino acids, and thus indicates higher digestibility.
Animal protein is one of the best sources of essential amino acids with high digestibility. Fish have BVs of around 75, and eggs have a BV of close to 95.
However, not all animal proteins have high BVs. Beaks and feathers although 100% protein, have zero digestibility.
Plant proteins like corn and soy have good BVs of between 60 to 70 which may seem like an excellent source of protein. However, this high BV score does not reflect high digestibility when given to our carnivorous companions who lack the digestive adaptations to breakdown carbohydrates.
Carbohydrates require the enzymes maltase and amylase to breakdown its nutrients for absorption. Carnivores, like our companions, have little to no salivary amylase and rely solely on amylase excreted from the pancreas. Feeding biologically inappropriate foods would not only decrease digestibility but also cause undue stress to organs such as the pancreas.
Case Study 1
Senior dogs fed varying amounts of protein from chicken and corn-gluten meal (CGM). One group had a 100% chicken diet and other groups had a mix of CGM and chicken.
Dogs fed 100% chicken diet showed better results
100% chicken diet reversed some age-related changes in skeletal muscles i.e. showed closer muscle mass to young-healthy dogs.
Improvement of body composition enhances the long-term health and well-being.
Case Study 2`
12 Mixed breed adult cats, fed 3 different diet formulations
Formulation: Meat meal, Chicken meal and Corn gluten meal respectively
Duration: 3 weeks/diet
Findings: Meals with meat based protein reflected better digestibility
Both case studies show that diets made with animal protein were more digestible when compared to plant protein and in cases where fresh food was provided, the results pointed to an enhanced long-term health and well-being.
A study conducted in Denmark compared the digestibility of mechanically separated raw chicken meat before and after cooking via extrusion (Kibble).
The digestibility of the raw chicken meat was found to be better at 88.2% vs. the digestibility of the processed chicken meat at 80.9%.
It was speculated that the digestibility was adversely affected due to the harsh heating and drying process of extrusion. Highly processed foods are unsurprisingly less digestible as compared to raw and/or unadulterated foods.
Protein quality in pet food can vary greatly, from highly digestible muscle meat to over processed animal by-product meals rendered from 4D animals; dying, diseased, disabled and dead. You can read more about in our previous blog post, “Icky or Iffy, Pet Grade vs. Human Grade”.
Ask yourself these questions to determine how digestible your companion's diet is.
How much poop do you scoop?
Is your companion producing more poop that you’d expect for his size and dietary intake? If so, it may be time to reconsider his diet and explore other options.
What's in your companion's food?
High quality ingredients such as whole meats are more digestible than meat meals, and animal protein more digestible than vegetable proteins. Does your companion’s food label consist of more vegetables/grains or meat products as it’s primary ingredients (listed at the top)?
How is the diet made?
Is the diet minimally process with little or no heat applied or is it heavily processed and extruded at high heats and under extreme pressure?
How much does it cost?
As the Chinese proverb goes, cheap things are not good, good things are not cheap. High digestibility and quality ingredients cost more so if the pricing is too good to be true, it's likely too cheap to be good. Conversely, you might be paying top dollar for low quality food. It's important to look at the quality of ingredients.
We hope that this has encouraged you to take a closer look into your companions diet and choose foods that are minimally processed.
We update our blog every Monday and Thursday. Follow us on Instagram and Facebook so you won’t miss out any updates.
Until next time, keep your tails wagging.
*Curious to know more about the studies we mentioned? Drop us an email and I will send you the links!