Very, very glad that Fister came through his check-up so well. It is worrying when they get older and you feel such a thrill when their results come back in normal range. As to the alat increase, perhaps he has a slight infection in his liver? This won't give him a temperature but can cause in slight increase in that level. If your vet thinks that, he will give you some antibiotics for Fister, but it may be so little over normal that he feels it's of no concern.

We will look forward to seeing photos of Fister in his garden in a few months time.