2.5. Total Tract Apparent Digestibility

Dogs were housed individually for five days at weeks 5, 10, 15 and 20 to allow total feces collection. Individual fecal samples were scored using a 5-point scale (from 1, corresponding to a liquid stool, to 5, corresponding to dry and hard feces [26]), weighed, placed in plastic bags and stored at −20 °C until further analysis. A representative sample from thawed samples was immediately analyzed for Kjeldahl N to allow CP calculation (Kjeldahl N × 6.25). Ash, ether extract, NDF, ADF, starch, GE and P were analyzed from dried (65 °C) and milled (1 mm) feces pooled per dog and period. The coefficient of total tract apparent digestibility (CTTAD; g/kg) was calculated as follows: