A new study suggests that both cats and dogs showed a short-term preference for kibble containing protein derived from microorganisms, such as fungi, yeast, or bacteria, over kibble with traditional animal-based protein. The research was conducted by Ally Motta de Matos and A.L.B. Cruz from MicroHarvest, a European company that produces protein ingredients using fermentation. Their findings were published in PLOS One, an open-access scientific journal. This study marks an important step in exploring sustainable alternatives to traditional animal-based proteins in pet food. Pet food has traditionally relied on animal sources like fish and poultry for protein. However, growing concerns about the environmental impact of raising animals for food, along with questions about the long-term availability of these resources, have increased interest in alternative protein sources. Microbial proteins, produced through fermentation, offer a potentially sustainable option. Previous studies have shown that these proteins can be nutritionally valuable, but their success also depends on whether pets actually enjoy eating them. To test the appeal of kibble with microbial protein, researchers asked pet owners to offer their cats or dogs two bowls of food at the same time for four meals over two days. One bowl contained standard kibble with animal-based protein, while the other had nearly the same formula but with some of the animal protein replaced by microbial protein. The study involved 30 dogs and 30 cats, with all meals given at home. The results showed that both cats and dogs consumed a higher proportion of the kibble containing microbial protein. Dogs ate about 72% of the microbial-protein kibble compared to 50% of the standard kibble, while cats ate 51% of the microbial-protein kibble versus 34% of the standard kibble. In both groups, the animals were more likely to approach and eat the microbial-protein kibble first. The researchers noted that the short-term preference for microbial-protein kibble is encouraging, even though the microbial protein replaced fish meal and part of the poultry meal in the formulation. These findings suggest that microbial proteins could be a viable option for pet food, not only in terms of nutrition but also in terms of palatability. However, the researchers emphasized that more long-term studies are needed to assess how well pets tolerate and benefit from these proteins over time. They also highlighted that while nutritional quality is important, the food must ultimately be appealing to the animals in order to be successful in the market.