112 Determining the Required Length of Adaptation and Fecal Collection Periods for in-Home Digestibility Testing of cat Foods

Abstract In-home digestibility testing of pet foods has advantages over the standard procedure of testing in kennels. Existing test protocols must be adjusted for use in-home, e.g. regarding periods of adaptation and fecal collection[1]. We evaluated the minimal durations of these periods for in-home digestibility testing of cat foods. In a cross-over design, 26 privately-owned indoor cats (16♀10♂; 1-16 yr; 3-8 kg) were fed two extruded cat foods of contrasting digestibility (Food A high, Food B low) and containing 0.1% titanium (Ti) dioxide. Consecutive feeding periods (1, 2) lasted 8 days and owners collected feces daily. Foods and daily feces were analyzed for Ti, dry matter (DM), nitrogen (N), crude fat (CFat) and gross energy (GE). Fecal Ti concentrations and digestibility values were analyzed with repeated measures ANOVA and post hoc Tukey test, within each combination of food and period. Feces were collected on 320 out of 416 study days, implying the necessity for multiple collection days to account for long intervals between defecations. Fecal marker concentrations were constant from day 3 (Food A) and 2 (Food B) onwards in both periods (Figure 1a,b). In period 1, when cats received Ti for the first time, CFat digestibility of food A was constant from day 1 and DM, N (Figure 1b) and GE from day 3 onwards. For Food B, all digestibility values were constant from day 2. In period 2, CFat digestibility of food A was constant from day 2 and that of DM, N (Figure 1d) and GE again from day 3. For Food B, N digestibility was constant from day 1, GE and CFat from day 2 and that of DM from day 3. In-home digestibility testing of cat food seems to require 2 days of adaptation and 3 days of fecal collection. [1] FEDIAF (2021), nutritional guidelines, fediaf.org