The prefix 'eu-' means 'good' in Greek. The 'kanuba' part may be meaningless. The good part is ironic as the animal rights group PETA claims that Eukanuba is very bad for animals.
The Eukanuba and Iams brands are both owned by Procter and Gamble.
PETA argues forcefully that Iams/Eukanuba are guilty of extreme animal cruelty by funding research where dogs gums were deliberately and repeatedly cut open to cause gum disease. Various food formulas could then be tested for their effect on this gum disease.
PETA also argues that Iams/Eukanuba (in common with most pet food companies) has very inhumane standards for testing of their foods. The essence of their complaint is that test animals are kept in small concrete and metal cages.
It's difficult to find mainstream petfood brands that treat their test animals well. That said, Newman's Own is considered humane and is widely available.
My own cats enjoy "Evo" made by a small company called "Natura".
Even allowing for a PR writer's hyperbole, Natura's attitude to testing may be a good model.