Small animal Review

Additives are virtually omnipresent in processed pet foods, and a recent paper by Craig (2021) reviewed their safety, efficacy, labelling and ethical concerns regarding existing toxicity testing in laboratory rodents. It is argued that LD50 studies are not useful for determining how much of an additive can be eaten safely by a person or domestic pet, but the more appropriate feeding studies are conducted much less commonly. Additive testing procedures are often outdated and reported in secret dossiers by, or on behalf of, the company seeking authorisation, taking no account of interactions with other additives and dietary components.

Effects on the microbiome are not typically investigated, despite studies indicating that additives can induce microbiota-mediated adverse effects on the host. In both dogs and humans, disruption of the gastrointestinal microbiota (dysbiosis) may be associated with clinical disorders, not only in the gastrointestinal tract but also in the brain, skin, joints, and immune system. Emulsifiers, widely included in pet food to prevent separation of ingredients, and create the gravy or gel in canned, sachet and other moist pet foods, have been found to cause obesity and metabolic abnormalities in mice, and may increase the risk of inflammatory bowel disease and other chronic inflammatory diseases in people.