Chemical composition of Tanganyika grass under tree shading levels in a silvopastoral system

ABSTRACT This study aimed to evaluate the effect of different Clitoria fairchildiana tree shading levels on the Tanganyika grass (Megatyrsus maximus Jacq. cv. Tanganyika) chemical composition, in summer I (2011/2012), spring (2012) and summer II (2012/2013) seasons. For this purpose, an experiment was conducted in a completely randomized design with four treatments (shading levels) and five repetitions at Seropédica, state of Rio de Janeiro, Brazil. The following variables were evaluated: dry matter (DM), crude protein (CP), neutral detergent (NDF) and acid detergent (ADF) fiber, neutral (NDIP) and acid (ADIP) detergent insoluble protein, lignin (LIG) and mineral matter (MM) contents. Data were analyzed by PROC MIXED SAS®, with repeated measures in time, and treatment means compared by Tukey’s test (P<0.05) or by PROC REG (P<0.05 for regression analysis. There was a significant interaction between season and shading level for DM, CP, NDF, ADF, NDIP, ADIP and MM contents (P<0.05). Lignin content was only influenced by shading level (P<0.05). The DM, NDF, ADF and lignin contents were reduced by shading increase while CP, NIDP and MM contents were increased. Higher ADIP contents were found only in the spring. The increase in Clitoria fairchildiana tree shading improves the chemical composition of Tanganyika grass forage during summer season.