Melamine caused severe illness and death in sheep in this South African study. It’s safe to say that further testing is needed to determine how small amounts over time will affect pets and people alike.
With 10 g daily one sheep did not die but 2 did so after 16 and 31 days. The 2 sheep which died lost appetite and stopped urinating 3 days before death and urea and creatinine in blood then increased sharply. There were crystals in the kidneys and severe oedema of the lungs.
NOTE: South Africa’s pet food association is recommending the removal of all Chinese ingredients.