Amino acids are the building blocks of protein, so anything that has protein has amino acids.

I don't really know what specifically fish kelp is supposed to do or what it has in it that other organic fertilizers don't have, so I don't know whether this would be able to fully replace fish kelp or not.

Bradfield makes an excellent product, buts its kinda costly for me atleast. I created my own version of there product for much cheaper. Get some Alfalfa Pellets from a local feed store and spread them @ 10-201bs per 1000sqft. Then buy some Unsulphured molasses at the grocery and spray it after you spread the alfalfa @ 2-4oz per gallon to cover 1000sqft. I dont do this last step, but if you wanted to you could spread 1-2 lbs per 1000sqft sulfate of potash

I would keep the fish/kelp in your rotation if you like it. You could alternate between the two.