Comparison of cassava fiber with conventional fiber sources on diet digestibility, fecal characteristics, intestinal fermentation products, and fecal microbiota of dogs

The objective of this study was to evaluate the influence of cassava fiber (CA) concentrations and conventional fiber sources on coefficients of total tract apparent digestibility (CTTAD) and metabolizable energy (ME) of the diet, fecal characteristics, intestinal fermentation products, and fecal microbiota of dogs. Seven diets were evaluated: control diet (without the addition of fiber sources); three diets with increasing concentrations of CA: 40, 80, and 120 g/kg (totaling 61, 72, and 83 g/kg of total dietary fiber, TDF, respectively); diet with 38 g/kg of cellulose (CE); diet with 60 g/kg of beet pulp (BP); and diet with 38 g/kg of lignocellulose (LC). Diets with 120 g/kg of CA, CE, BP, and LC contained approximately 80 g/kg of TDF. Diet digestibility, fecal characteristics, intestinal fermentation products, and fecal microbiota were evaluated in 14 adult Beagle dogs, distributed in a randomized block design, with 3 periods of 15 days each. Each 2 dogs were fed one of the diets per period, totaling 6 replicates/treatment at the end of the 3 periods. The CTTAD of organic matter and dry matter was higher (P < 0.05) in the control diet when compared to diets with the same TDF concentrations. The 120 g/kg CA diet had lower ME when compared to the CE and LC diets (P < 0.05). There was no difference among diets on fecal score and ammonia (P > 0.05). The 120 g/kg CA diet resulted in higher fecal concentrations of acetate and total short-chain fatty acids (SCFA) when compared to the control, CE, and LC diets (P < 0.05). Effects of fiber-containing diets on fecal microbiota were observed mainly for BP and CA diets, which increased bacterial richness and α-diversity and the relative abundance of Faecalibacterium, Fusobacterium, and Bacteroides, when compared to the control diet (P < 0.05). Cassava fiber can be included in adult dog foods because it has similar effects to conventional fiber sources. Besides, it keeps the stool soft and well-formed and modulates the intestinal microbiota of dogs, increasing the richness and favoring genera with potential benefits, such as Faecalibacterium.