Digestibility of diets and nutritional value of torula yeast (Candida utilis) for rabbits (Oryctolagus cuniculus) and agoutis (Dasyprocta spp.)

The aim of this study was to assess the nutritional value of diets that contain torula yeast in rabbits and agoutis and the influence of torula yeast on the apparent digestibility of the nutrients. In the first experiment, 32 New Zealand White rabbits were fed diets with four different levels (0%, 5%, 10%, and 15%) of torula yeast that was substituted for soybean meal. The experimental design was completely randomized with four treatments and eight repetitions. The digestibility coefficients (DC) of dry matter (DM; DCDM), crude protein (DCCP), neutral detergent fiber (DDNDF), ether extract (DCEE), and gross energy (DCGE), as well as the mean daily consumption (MDC), were calculated (MDC: 113.98, 113.96, 113.22, and 115.07 g animal-1; DCDM: 71.04%, 69.98%, 67.79%, and 74.08%; DCCP: 80.17%, 79.55%, 75.10%, and 78.47%; DCND: 66.85%, 65.50%, 63.31%, and 70.12%; DCEE: 77.83%, 76.46%, 78.36%, and 82.07%; and DCGE: 71.04%, 69.98%, 68.37%, and 73.82%). No significant effects (P > 0.05) were found on the MDC or the DCs for the different yeast levels, and the inclusion of torula up to 15% did not affect diet digestibility. The digestible energy (DE) (kcal kg-1 DM-1) of a diet with 15% torula yeast was calculated as 2,870.52 with the methodology proposed by Matterson (MMT) and 2,870.89 when corrected by the methodology proposed by Villamide (MVD). Linear regression estimated the DE (kcal kg-1 DM-1) as 2,805.22. The digestible protein (DP; g kg-1 DM-1) of a diet with 15% torula yeast was calculated as 182.6 with the MTT method and 190.9 with the MVD correction. Linear regression estimated the DP (g kg-1 DM-1) as 293.0. In the second experiment, 20 agoutis were divided into two treatment groups: a control group and one given a base diet containing 30% torula yeast. The experimental design was completely randomized with two treatments and ten replications. The DCDM, DCCP, DCNDF, DCEE, DCGE, and the DCs of organic matter (DCOM) and mineral matter (DCMM), as well as the MDC, were calculated (MDC: 84.48 and 90.48 g animal-1, DCDM: 67.62% and 67.06%, DCCP: 71.12% and 68.l9%, DCNDF: 72.70% and 69.89%, DCOM: 70.52% and 20.27%, and DCMM: 36.27% and 33.16%), and no significant differences (P > 0.05) were found. The DCEE (63.39% and 48.04%) and DCGE (68.00% and 63.73%) results differed significantly (P < 0.05). The DE (kcal kg-1 DM-1) of 30% torula yeast in the diet was calculated as 1,714.22 with the MMT method and 1,663.69 with the MVD correction. The DP (g kg-1 DM-1) of 30% t