Protein Intolerance Cat

Sorry, this might be a bit of a long read, but even so, leaving alot of details out or it would take me a day to write.

It's been almost 15 months since we adopted Benny from a local rescue.  He's 6.5 yrs old now, and during most of that time, we have been trying to figure out why he was having mostly soft stools sometimes with blood in them. I tried LID diets, elimination with novel proteins, you name it, nothing really worked until I finally gave in and transitioned him to a kibble only diet of the prescription Royal Canin Hydrolized Soy HP.  I was avoiding it due the the extremely high percentage of calories from carbs...empty calories that do not satiate him.  More on that later.

After only a couple of days, his stool began to firm up, darken and smell much less.  Great sign.  And he was happy because no need to have his bum cleaned after every bowel movement (med-long coat, so just imagine).  Also, I suspect he had tummy discomfort but as we all know, felines hide pain and discomfort well.

After 2 months of awesome looking stool (and solely eating the RC kibble + water), I began to introduce one ingredient at a time into his diet for a period of 7-10 days, with a break in between each.  To start, I focused on those ingredients that were common to the previous foods we had tried with him, then moved to ingredients that were not.    There was clear observation of one ingredient having any impact.  We think chicken may have softened his stool, but it was only one occurrence.  That left us scratching our heads.  Regardless, we thought, as did our vet, that he has a protein intolerance, or that his digestive system had difficulty breaking down proteins.  We just did not know if it was one protein in particular or all proteins.  The interesting thing is the gab in time between bowel movements was correlated to how soft his stool was.  Smaller the gap, the softer the stool.  In the meantime, however, Benny gained almost 2lbs in 2.5 months.  Poor guy was always hungry for more because carbs don't fill him up.  He was never an "over-eater" previously and always free fed on kibble.

So we decided to bite the bullet and try introducing a wet food again.  However, ideally we could find a hydrolyzed meat protein.  No such luck.  Nothing seems to exist for felines.  After searching high and low for a single protein food (we had to compromise since hydrolyzed was not an option)  we found the Farmina ND Digestion wet food with only two proteins.  The first is lamb, which is novel to him, and the 2nd, hydrolyzed herring.  Also, like most wet food, kcals was about 1/3 that of the RC kibble.  Also, carbs make up significantly less percentage of the calorie.  So all good things.  We started slow and slowly increased the wet while reducing the kibble, always tracking his daily calorie intake.  It was going well.  We tried Farmina duck and pumpkin mixed in, as well as their Weight mngt, which is same as digestion except a bit more herring it would seem, and two different veggies.

The other thing about the Royal Canin is that it is soy based.  There are different points of view on whether this is good or not, but some point to long term negative effects of a soy diet in felines.  

With that also in mind, and things going well, we started looking for an alternative kibble.  We settled on Acana Pacifica...fish based with no chicken or other protein ingredients buried in there.  Few other filler ingredients.  We figured he did well with herring, so this might work.  Started off good, and we transitioned slowly, as in what one would normally transition over 7 days, we did over 4 or 5 weeks.  We got to about half and half Acana and RC, and his poop started going a bit wonky, with the odd soft portion of stool being soft.  Last week, he had some soft ones and for the first time in many months, I saw blood in one of his stools.  We stopped the Acana, stopped everything except Farmina digestion and RC.  We also reduced the wet food and slightly increased the RC.  We are on day 4 and his stool is got better and today, nice darker firm stool.  Whew!

But, we are at our wits end trying to figure this out.  And why oh why is there not one manufacturer that offers a hydrolyzed meat based food?

Any thoughts or suggestions are welcome.