Oxidized dietary fat, alkaline phosphatase concentrations and performance in racing greyhounds

Racing dogs are often fed raw meat. Raw meat may become oxidized because it contains no preservatives but few studies have examined the effect of feeding oxidized food to dogs. This study was originally designed to determine the effect of different concentrations of dietary fat on greyhound performance. After the experiment had been completed, however, it was discovered that the peroxide values (PV) of both diets were elevated indicating that fat oxidation had been present. This study was considered to have value, therefore, because it compared performance and blood parameters in eight trained Greyhounds fed either a high fat moderately oxidized (HFMO) diet (43%ME fat with PV of 44 mEq/kg) or a medium fat highly oxidized (MFHO) diet (31%ME fat with PV of 211 mEq/kg) for 8 weeks per diet in a randomized cross-over design. Dogs were raced over 500 m twice weekly. Race times over the last 4 weeks of each diet period and blood parameters before racing during the last week of each diet period were compared. Dogs fed the MFHO food ran 0.04 m/s slower (p = 0.06) and serum alkaline phosphatase concentrations were higher (149 vs. 56 U/L; p < 0.0001) than in dogs fed the HFMO diet. Further evaluation is needed to determine whether lower dietary fat or increased oxidation was responsible for the altered performance but oxidation of the food should be considered as one possible explanation for an increase in serum alkaline phosphatase during a diet trial.