I have read the comments re various foods, & (possibly not wholly definitive), prognosis & diagnosis. I am very mindful the dog has been opened up with some invasive exploratory work, & testing going on.
A big red flag for me is you say your vet has stated they do not think your dog has food allergies yet you have been advised to feed a well known vet pushed HA food !!!!
Don't rule out a K.I.S.S. ( Keep It simple stupid)..........if it sits better replace the word stupid with "strategy".
To me, in back of my mind I was be thinking along lines of.............
Young dog + Scavenging + Fussy eating + Food changes &/or wrong amounts = Diarrhea
Colitis, Giardia , IBD (or maybe IBS)........the result is the same........... Diarrhea
...........How would I deal with it ?
Dealing with dog Diarrhea
1. Supervise all activity to eliminate scavenging, ( this includes eating mud, garden matter faeces etc)
2. Starve the dog & give water only for 24hrs or maybe a bit longer
3. Feed one bland white meat protein & that alone (some say add rice - in my experience it can hinder recovery)
4. Monitor output, Cut back or revert to 2 if loose again....
5. If ok gradually re-introduce original food.
6 IIf still loose after 3 days consider Vet &/or AB's etc
Managing a True Elimination diet.............
Only feed one bland protein source NOTHING else
White fish for 10 days
Cooked chicken 10 days
Cooked beef 10 days
Monitor ( output, skin, eyes, condition, itching ) etc etc etc
If you manage to find 3 tolerable protein sources you have more than enough to use these as a base for meals. Apply similar process if introducing other stuff to the bow.
You again speak of other food brands....the compositions of bought foods have many many ingredients. If you feed a certain brand with multiple ingredients in composition you may have no idea what the problematic one is in the event dog becomes loose on it...Dottie is the go to for home cooked advice.
Your thoughts have already swayed from air dried (ziwipeak air dried claims to be good but very expensive) & now mention cold pressed & the brand Gentle.........If later looking at cold pressed, wanting a decent food from a trusted brand with great ongoing customer support you will struggle to do better.....With cold pressed foods the binders get reckoned as carbs on here. ...Some cold pressed foods rely on potato flakes others use mineral clays etc etc. Beth @ Gentle may be able to explain more.
It may well be that you have a dog with a multitude of various issues going on BUT IMO you are massively overthinking things & adding far too many variables........wet, dry-extruded, air dried, home cooked , cold pressed, fillers, not to mention Cassia gum (I had never heard of before your post & Davids response)
If the dog is currently doing okay - maybe don't rush to do anything !
Thank you for this Coaster, such good information that I have copied and pasted it into word and saved the document.
I feel I may have misled you with my comment about a local outbreak of a virus causing diarrhoea in dogs (I don't know if it caused vomiting or not). I had settled on Arden Grange kibble with a topper of Lukullus wet food which did seem to suit my dog until the afternoon of Monday 9th December when she vomited bile, refused to eat. I did think she may have eaten something that had caused this. I offered boiled white fish 24 hrs after her last meal. That was ok, fed her fish again later in the day with added rice - she vomited the lot undigested. Saw a vet following day, anti sick jab and asked me to bring a poo sample. She was able to eat boiled white fish or chicken breast while the anti sick jab lasted but started vomiting again after a couple of days. Unfortunately, don't often get to see the same vet and the next one (franchise partner) wasn't interested in poo sample. Mia was on meds and getting worse until 19th December when they ran tests and opened her up. I opted for the overnight in Vet hospital for her as she needed hydration and meds to restart the peristalsis. She did have some diarrhoea but eventually it was massive gas and just liquid. I was told that when she was opened up, apart from inflammation, she was full of water and mucus. I believe he said they washed her tummy out.
I wasn't convinced about the Purina HA but I have to say she did well on it and her tummy was fine. In fact probably better than ever. I should mention, she was five months old when I got her: very travel sick, if pulled on lead she was sick, doing zoomies round the garden would make her sick (very difficult to stop her zooming as she is pretty quick and agile). Her poo was quite often copious with mucus (maybe she had IBS).
I hadn't thought to just feed her one protein and only that, I will bear that in mind should any future need arise. What I have done is use the Purina as a base starting point and given her a small amount of either home cooked white fish or chicken breast, or meat/fish with veg. or a small (topper) portion of wet food just to try. Added a small amount of a different kibble if ok - if any of it had an adverse affect I took it back to base.
I have not tried anything completely different yet as I was reaching out for information, then researching it. I have concluded that maybe I will try the Pure Vegi plus and add the protein or maybe the Gentle cold pressed - this is because I feel that extruded kibble may not be the best food for her, even though before she was ill, the Arden Grange and Lukullus wet food did seem to agree with her. Also some of the wet food has carrageenan (which was red now orange alert on AADF) and thickeners like Cassia Gum (which is often used with Carrageenan). Some research suggested that Carrageenan can be altered by the acid in dogs stomach to make it an ingredient that causes inflammation. I don't want to take any chances.
It doesn't help that one day she will eat with relish and the next it is poison
Thank you once again for your input.