Cats and dogs prefer a surprising new protein source in their food

Cats and dogs showed a clear preference for pet food containing microbial protein in a new two-bowl feeding study. Researchers tested kibble in which microbial protein partially or fully replaced conventional protein ingredients against a standard formula designed to mimic fish-and-rice. In four meals over two days, 30 dogs and 30 cats were offered both bowls at once; bowl positions switched every meal, and the coding ensured owners did not know which bowl contained which diet. Microbial protein fully replaced the fish meal and partially replaced the poultry meal, with a slight increase in poultry fat to keep nutrition comparable. Results favored the microbial-protein bowl: dogs ate about 72% of it versus 50% of the control, while cats ate 51% versus 34%.