Optimizing omega-3 supplementation in chronically ill dogs: The impact of body weight and dietary inclusion rates.

Nutritional supplement dosages for dogs are often expressed relative to overall body weight (BW). However, daily food intake scales with metabolic weight (BW0.75). This discrepancy implies that the ingested dose of supplements included in diets does not increase linearly with BW. This study evaluated the impact of this phenomenon on omega-3 supplementation, comparing the theoretical efficacy of extruded therapeutic diets using cardiac (dosage expressed by BW) and chronic kidney disease (dosage expressed by BW0.75) dosage models. The theoretical dietary intake of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) was calculated for dogs weighing 1 to 80 kg consuming their maintenance energy requirement. Four cardiac and seven renal therapeutic diets were evaluated based on their declared metabolizable energy and omega-3 inclusion rates. The theoretical dietary intake for each body weight and diet was compared to recommended dosages for the diseases. For cardiac disease (40 mg/kg EPA and 25 mg/kg DHA), the intake-to-recommended ratio decreased as BW increased. Diets met targets only for dogs up to 2.5, 5.3, or 22.7 kg, with one failing entirely. For chronic kidney disease (140 mg/kg0.75 EPA + DHA), the ratio remained constant across all weights, providing 42.4% to 79.1% of the recommended dose. Expressing target dosages based on overall BW limits the efficacy of dietary supplementation for larger dogs. Commercial therapeutic diets may still contribute by reducing the need for extra-dietary supplementation, although the need for and magnitude of such intervention must be individually assessed.