Source of protein/fat
Does the source of protein in a dog food make a difference. I don't want to get into a brand debate. If one food has a 30/20 protein/fat ratio from chicken and corn, will another food that has 25/15 from fish and no grains be just as good for a working dog? Or is protein, protein regardless of its source?
I'm not a nutrition expert but based on the Biochemistry classes I took, I would say no. Different protein sources will be metabolized into different Amino Acids.-Paul
Originally Posted by Thomas D
Protein is NOT protein, regardless of the source. Your boot leather is very high in protein. It's even from an animal source, but it's not very digestible. Plant proteins like, corn gluten meal, are incomplete proteins because they don't contain all of the essential amino acids a dog must get from his diet, yet it counts as protein on the Guaranteed Analysis printed on the bag.
Without getting into the brand debate, I prefer as much protein from animal sources as possible, fat from an animal source rather than a plant oil, and I do like the grain-free concept. However, many of the grain-free foods replace the grains with an abudance of potato and/or pea ingredients. So just because a food is grain-free doesn't necessarily mean it is low carb or even higher in protein than a conventional grain based food. In fact some grain-free foods contain "pea protein" or "potato protein" as an ingredient. I don't know if that would be an increase in protein quality over corn gluten meal.
There's more to consider when buying dog food than the Guaranteed Analysis and the advertising.
Protein Source can defiantly make a difference, especially if you dog is allergic to a certain one. The Animal vs. Plant protein debate is something to look into, Animal protein digests much easier/ faster. However if a Protein source is too digestible, it runs through the system quickly, sometimes without enough time to be absorbed and utilized, and you pay for expensive poop. An over abundance of such Protein can also result in the lovely experience of loose stool ;). Plant Proteins take more time and calories to digest, if they are too hard to digest they also come out the back end, hard stool and constipation ;). As a Protein corn is quick to digest and provides quick energy, whereas a soy or rice plant protein is harder to digest giving more long term calories. In the end Protein is Protein the question is which protein can a particular dog digest and utilized the best.
If you look at any high end performance dog food bag, almost every ingredient has a specific function in the formulation, even so called fillers are put into aid in digestibility. The question is basically which formulation will work best for a particular dog, and there's great variety in that.
The no grain debate is primarily based on the assumption that a lot of dogs may develop allergies to particular grains (ie Corn). However a lot of dog also develop allergies to particular meat sources, chicken being the main culprit. Corn and Chicken have been primary ingredients in U.S. dog foods for generations, over exposure to certain food sources has a tendency result in allergy, in prone individuals. Ex; Over-exposure to a particular food proteins, is the reason people who could once eat seafood, avocados, milk, peanuts, can become deathly allergic to them later in life. If your immune system chooses to recognize that protein as an invader, your screwed, If you bombard your system with a bunch of a certain protein, your immune system is more likely to call it an invader and your screwed ;) Oh how I miss my Crab & Shrimp, why did I have to eat so much of you :( This is probably why Gluttony is a sin ;) The same is true for dogs, in Australia there are many dogs who have even developed allergies to Kangaroo, as that is a main protein source down under.
Yes, the source matters. The issue is what is known as bioavailability or biological value. In a nutshell, it's simply a matter of how easily metabolized the protein source is. Chemically speaking, you could have two protein sources with the same chemical protein content percentage but that have very different biological values. Keep in mind that hair and feathers are mostly protein but are virtually impossible to digest before they pass through the digestive tract. The site below has some good information on this.
Originally Posted by Thomas D
When a wild animal kills it will eat the entrails first...The meat eater needs the grains ( grass ) from the vegetarian to balance its needs ...The greater number of ingredients you have in the formula the better off you are ...Each item brings a specific item to the total...As we need different sources of proteins for a balance diet so do the dogs...same for veggies... Steve S