But you started this with a concern for digestibility, good absorption of nutrients, stool size, and gas. So I wanted to comment on that.
“I don’t know if having more animal protein versus plant protein would help her digest the nutrients and poop/have gas less?”
In short, no. It is the quality of the individual ingredients, what they are and their grade, that affect digestibility as they go into a formula. You’re also playing a balancing game with some ingredients, between rich in nutrients and greater digestibility. From there, processing matters. It can affect overall digestibility and preservation of nutrients. Finally freshness of ingredients going into the formula and from date of manufacture to purchase and use are very important.
I would highly recommend calling the company of the the foods you’re considering, as well as the one you’ve been feeding (Infinia) and asking for Total Dry Matter Digestibility, plus digestibility of protein, fat, and carbs.
The Infinia is rather low in protein, lower than I personally would feel comfortable feeding. But that isn’t the problem when looking at nutrient absorption and digestibility. But when the protein IS very low, then it becomes even more critical to ensure that it is very high quality and highly digested.
Since Infinia Holistic Salmon & Sweet Potato’s primary ingredients are ones that look good and CAN be highly digestible . . .
Salmon, Menhaden fish meal, sweet potatoes, potatoes
it may the grade of ingredients and/or processing that is problematic.
Fish meal, for example, comes in MANY different grades at VERY different price points to pet food companies. It can be very high ash & bones, leftover carcass material or low ash/high protein & high digestibility and come from good cuts included or whole fish with most bone filtered out, which costs the company considerably more and is harder to source. It also, by AAFCO definition, can be stripped of its oil (which is sold separately at profit, rather than going into the food) or have those precious Omega 3s left in. This formula appears to be very low in Omega 3, particularly for a fish formula, and even though it has been already boosted by plant oil (Canola). Reasons for fish formulas to be low in Omega 3 tend to be the meal has been stripped of its oils and/or use of farmed salmon. Salmon varieties also range greatly in Omega 3 content!
Canola oil is not going to be as digestible and its nutrients absorbed well in order to be used by your dog vs., say, salmon oil or an animal fat. (I personally don’t like canola oil anyway, as it’s not a very clean ingredient. In commercial use, it is generally high heat and chemical processed, damaged, and and contaminated.) Potatoes, sweet potatoes can include skins or not, etc. affecting digestibility and stool volume.
Foods cooked for less time and at lower temperatures preserve more nutrients. And gentle cooking both increases digestibility and nutrient absorbability in ingredients and nutrients AND decreases them compared to raw, depending on the ingredient or nutrient.
Consider how fresh the ingredients are, how fresh from date of manufacture, how it was stored and transported prior to getting to you, and how properly sealed the bags are. (From there, you must also store foods properly.) Actually smell the food.
But just to give you an example of how you can never tell with things like digestibility from the price and marketing/popularity of a product or just looking at the ingredient list of a “better” brand — Orijen’s 6 Fish formula has a pretty poor overall dry matter digestibility for a premium brand and is in fact the lowest among their formulas. It’s also lower than the cheap bulk bags from Costco, Nature’s Domain (by Diamond).
