Dogs fed a high fat diet have reduced plasma taurine concentrations

Diets affecting taurine synthesis or excretion may result in alterations of plasma taurine concentrations (PTC). The purpose of this study was to determine effects of dietary fat on PTC in dogs fed a protein-restricted (10% DMB) diet. Diets were either low fat (LF; 13.3% DMB) or high fat (HF; 24.4% DMB). Twelve beagles were assigned to 1 of 2 diet groups. PTC were determined at baseline and at the end of a 6 month feeding period. Normal canine PTC=41 to 97 nmol/ml. Baseline mean PTC+/-SD for LF and HF groups were 70.5+/-12.7 and 66.8+/-15.4 nmol/ml, respectively. All individual PTC were within normal limits. After 6 months, PTC for the LF group=60.2+/-13.6 nmol/ml and had not changed significantly (p=0.2805), whereas the HF group had significantly declined to 30.7+/-14.2 nmol/ml (p=0.0006). These data show that dogs fed a protein-restricted and HF diet had PTC lower than normal range, whereas dogs fed the same diet but LF did not. Both diets were adequate in precursor amino acids, so decreased taurine synthesis is not a likely cause for these data. One possible explanation may be the HF diet resulted in greater taurine loss via excretion of bile acids. Dogs, like cats, preferentially conjugate bile acids to taurine, so the HF diet may have increased fecal taurine loss and/or colonie taurine degradation by bacteria.