Siamese mix with sensitive stomach

Hi all, new member here.

I have 2 lynx-point siamese mixes, both fairly young (8 months and 5 months) and in good health, with one exception.

My little female, Athena, has terrible gas and chronically soft (gloopy) stools. She was about 4 months when we adopted her, and has had these problems since then. We noticed the gas when we picked her out at the adoption fair, but didn't think much of it at the time. Now, over a month later, it's still happening.

We have taken her to the vet and done stool tests. She was prescribed 7 days of Metronidazole just to be safe (and finished all her doses) but ended up testing negative for parasites.

At this point, the only other thing I can think it might be is her diet. I'd originally dismissed that as the cause because she was shifted (gradually) off the food the shelter was giving her with no improvement, but I've heard that siamese can have particularly sensitive stomachs, so I'm wondering if there's something in both foods that might be causing the issue?

The shelter had her on Natural Balance dry. I've been feeding her Blue Buffalo Healthy Growth for Kittens dry (our other kitten, Apollo, is also on this with no issues).

Does anyone have recommendations of foods that might be ideal for sensitive stomachs? Ideally I'd like to eventually transition her to a blend of wet and dry, I've just been wary about doing that yet as I wasn't sure if wet food would make her stools worse.

I always hear wonderful things about Wellness, so I'm considering trying that, but since stomach sensitivity, in addition to quality nutrition, is a concern here, I was hoping someone familiar with these issues might have some good advice.

Thanks!

I gradually increased the proportions of new food over a 10-day period.

I know she was tested for giardia for sure, since the vet said her symptoms suggested it could be that. I'm not sure what else they tested her for, but I told them she'd been dewormed by the shelter before we adopted her, so I'm guessing they tested for things that were less likely to be treated by a basic dewormer.

The vet didn't seem concerned when her tests came back negative, but if this continues beyond a diet change, I'll definitely have her tested again to be safe, or ask if there are other parasites they may not have tested for.

She doesn't have outright diarrhea, which makes me less nervous. Just very soft smelly poo. Kind of toothpaste consistency.

I'm not really sure how that would help though? She had the problem on the old food as well. The problem did not start after we switched her to her new food, it's been happening since before we brought her home.

Its ingredients are fairly similar to her current food, my assumption was there's likely something in both that she's not reacting well to, possibly one of the grains.

The vet was the one who suggested the issue might be the food, since here parasite tests came back negative.

The only grain-free food I found at Petsmart was By Nature, which claims it's fine to feed to kittens and adults. I've yet to check, but I think I can find something like Wellness CORE at a different local store.