Plant-Derived Functional Ingredients in Pet Nutrition: Phytochemical Classification, Mechanisms, Efficacy, and...

This review classifies plant-derived functional ingredients in pet food according to phytochemical groups and application forms, including direct oral supplementation and incorporation into complete diets. Polyphenols and plant extracts exert prominent antioxidant (singular), anti-inflammatory, immunomodulatory, and microbiome-regulating effects. Microalgae and omega-3 sources support lipid metabolism, cardiovascular function, and skin integrity. Cannabinoids demonstrate dose-dependent responses in dogs, while cats generally tolerate long-term administration and exhibit notable benefits in chronic pain management. Combinations of botanical extracts with complementary bioactives and fermented botanical preparations exhibit multi-target functionality, with dogs showing pronounced biochemical and microbiome modulation, whereas cats display more behavioral and functional improvements. Phytochemicals operate through integrated multi-level regulation, including activation of antioxidant enzymes, modulation of inflammatory cytokines and T-lymphocyte ratios, microbial metabolic shifts toward short-chain fatty acid production, and regulation of lipid metabolism. Dogs demonstrate marked effects on hepatic function, reproductive resilience, microbiome diversity, CD4+/CD8+ balance, and cholesterol control. In contrast, cats show greater benefits in inflammation reduction, pain relief, intestinal integrity, and long-term safety. These species-specific responses underscore the importance of precision formulation and highlight the emergence of plant-based "pharma-pet nutrition" integrating nutritional and biochemical strategies for targeted health promotion.