Com o intuito de estudar o efeito de níveis crescentes de alimentos volumosos nas dietas de caitetus adultos sobre a digestibilidade dos nutrientes, foram testados 4 tratamentos com TA=25,25, TB=30,30, TC=35,00 e TD=40,00% de alimentos volumosos. Foi empregado o delineamento em blocos casualizados, utilizando-se de 24 caitetus formando 6 blocos de animais homogêneos. Os animais foram alojados em baias de alvenaria de tijolos e foi utilizado o método de coleta total de fezes. De modo geral níveis de até 35% de alimentos volumosos na dieta do caitetu não afetaram (P>0,05) a digestibilidade dos nutrientes. Foram inversamente correlacionados (P<0,01) os coeficientes de digestibilidade da matéria orgânica, matéria seca, energia bruta, extrativo não nitrogenado e da hemi-celulose com a concentração de constituintes da parede celular. Quando foi levado em consideração o grau de lignificação da parede celular da dieta fornecida, o caitetu apresentou coeficientes de digestibilidade da parede celular semelhantes aos observados em animais ruminantes domésticos

In order to study the effects of dietary roughage levels on nutrient digestibility of adult collared peccaries in a first experiment, twenty-four adult animals were assigned to four treatments (diets) containing: TA=25.25, TB=30.30, TC= 35.00 and TD=40.00% of roughage. According to the sex and body weight, a randomized complete block design was used with six replicates/treatment. The method of total collection of feces was employed. Addition of up to 35.00% of roughage in the diet did not affect (P>0.05) the digestibility of nutrients. The digestibility coefficient of organic matter, of dry matter, of gross energy, of hemicellulose and nitrogen-free extract were inversely correlated (P<0.01) to the concentration of the components of the cell-wall present in the experimental rations. When the cell wall lignin content was considered, the collared peccary showed cell wall digestibility similar to domestic ruminant animals. A second experiment was carried out to compare the nutrient digestion capacity of two different animal species. The stomach content of an adult male peccary and the rumen content of a cow were collected and used as inoculum to determine"in vitro"true dry matter digestibility. The substrates were the experimental ration with 40.00% of roughage (TD) and hay of Pennisetun purpureum (Schum). The average digestibility coeficients of dry matter of the diet and hay were, respectively: for cow, 75.86 and 74.43%, and for collared peccary, 66.64 and 58.43%