272. Effects of Dietary Supplementation of Algal Docosahexaenoic Acid on Fecal Characteristics, Fecal Metabolites, Blood Coagulation Parameters and Serum Chemistry of Adult Dogs.

Abstract Algal meal can potentially be used as an alternative to fish oil as source of docosahexaenoic acid (DHA) in canine nutrition. However, there is limited information in the literature on the effects of supplementing algal DHA oil in the diets of dogs. This study aimed to evaluate the effects of dietary supplementation of algal DHA meal on blood coagulation parameters, serum chemistry, fecal characteristics, and fecal metabolites in adult dogs. It was hypothesized that dietary supplementation with algal DHA meal would not adversely affect blood coagulation and serum metabolites, while promoting beneficial shifts in fecal metabolites in adult dogs compared to Control. Thirty-two adult beagles (avg. age = 5.1±1.6 years; avg. body weight = 11.0±2.3 kg) were included in this completely randomized design study. One dog was excluded due to health issues unrelated to this study. Following a 15-day adaptation period on the Control diet, dogs were assigned to one of 4 diets for an additional 90 days. The Control diet contained 10% chicken fat (CT) and the 3 additional experimental diets contained 2% fish oil (FO), 2% DHA-enriched algal meal (AL), or 4% DHA-enriched algal meal (AH) added as partial replacement of chicken fat. Fresh fecal and fasted blood were collected on days 0, 30, 60, and 90. No significant difference (P > 0.05) was observed in food intake, fecal output, fecal score, fecal pH, or fecal ammonia concentrations across treatment groups. However, significant treatment-by-day interactions were observed for fecal isovalerate (P = 0.0073) and isobutyrate (P = 0.0406). Dogs fed the AH diet had higher fecal isovalerate concentrations on day 90 (42.1 μmol/g) compared with AL on day 0 (25.3 μmol/g). Similarly, for isobutyrate, AH on day 90 (22.3 μmol/g) was higher than AL on day 0 (12.1 μmol/g). Fecal short-chain fatty acids, phenols and indoles concentrations did not differ (P > 0.05) among treatments. Additionally, no significant differences (P > 0.05) were observed in blood fibrinogen, prothrombin time, or partial thromboplastin time. Although within reference range, a significant treatment-by-day interaction (P = 0.0031) was observed with a decrease in serum triglyceride concentrations in AH-fed dogs from 62 mg/dL on day 0 to 46 mg/dL on day 90. In conclusion, dietary supplementation with algal DHA meal up to 4% of the dietary formulation was well tolerated, with no adverse effects on food intake, fecal characteristics, fecal metabolites, serum chemistry or blood coagulation, supporting its potential as an alternative omega-3 source in canine nutrition. On going analyses are evaluating fatty acid concentrations in serum and red blood cells, as well as potential effects of algal meal and fish oil supplementation on fecal microbiota composition.