
The trouble is recommending a specific food is it's virtually impossible. Especially given all the choice these days. On that basis alone, I'd go with the breeder's recommendation, at least initially. With my slow-maturing main breed, I didn't like to use anything with a protein level of much over 28%, if that. And I certainly didn't go for any of the current breed-specific food one major brand proiduces. The only difference in any case, is, usually, the size of the kibble pieces. If you use something too high in protein with big breeds, you risk forcing growth which alone can lead to problems later on. The boy of my breed I bought in had been reared on a well-known brand with a protein level of 32%. He was huge at 4 months and lame by 8 months with growth plate problems, ulna both sides, for starters. Lovely puppy, with so many things wrong with him it made me weep. And what he's cost us over the almost 9 years we've had him I can't look at. Last year he had further front to back x-ray after he was again experiencing bouts of lameness, showing he has subluxation of the hips, and other spinal problems that make me wonder how he's mobile at all. He's on Metacam and has been since then, and will be as long as he continues to tolerate it. Yes, he might have had these problems genetically of course, but I have no doubt in my mind that the main cause of how he is now, was incorrect food at the outset.
Be guided by whoever bred your puppy, who hopefully is experienced in the breed, would be my best advice.
ps We have had our boy, and his companion as it's more convenient to have them both on the same food, on Arden Grange for years now. First of all their Sensitive as, amongst all his other problems, came to us with Giardia and a 'sensitive tummy', and now their Adult Salmon and Rice