The objective was to evaluate the effects of diets with different fiber levels on pigs from different genetic groups during the growing phase. Sixteen castrated male piglets housed in metabolic cages were used. They were distributed in randomized blocks in a 2x2 factorial design, with two fiber levels and two genetic groups, resulting in four treatments with four replicates each. Dry matter (DM), crude protein (CP), mineral matter (MM), organic matter (OM), and gross energy (GE) of the feed, diet, and feces were determined to calculate the digestibility coefficients of the diets. Higher digestibility coefficients for DM (84.59%) and MM (33.11%) were observed in animals that consumed the higher fiber diet regardless of genetic group. However, the digestibility coefficient for ether extract (EE) (36.55%) was lower in animals fed the higher fiber diet. For digestible nutrients and energy in the diets, no influence (P>0.05) of genetic material was observed; however, diets with different fiber levels affected (P<0.05) the values of DM, MM, CP, EE, and digestible energy. It is concluded that digestibility coefficients of diets containing different fiber levels were not affected by genetics; however, diets with higher fiber content may alter nutrient and energy digestibility.
Falcão et al. (Tue,) studied this question.