Forage quality in cultivars of 'Brachiaria' spp.: Association of lignin and fibers with anatomical characteristics

Studies to quantify lignin and fibers chemically and anatomically were conducted to evaluate the nutritional quality of forage. This study aimed to assess differences in the amount of lignin and fiber in the leaves of cultivars from three species of 'Brachiaria'. These differences were correlated with structural characteristics of sclerenchyma and vessel elements. 'Brachiaria brizantha' (Hochst.) Stapf. cv. Marandu, 'Brachiaria decumbens' Stapf. Prain. cv. Basilisk, and 'Brachiaria ruziziensis' Kennedy (R. Germ and Evrad) cv. Kennedy were chemically and anatomically analyzed using fluorescence techniques and plant microtechnique procedures to evaluate the amount of lignin and fibers in leaves. 'B. brizantha' showed the lowest cell-wall lignin content in fibers from the mesophyll region, and the average gray level was 177.43 compared to 197.63 for 'B. decumbens' and 195.77 for 'B. ruziziensis'. In the midrib, the fiber cell-wall thickness was 3.27 mum in 'B. brizantha', 57.18% thinner than 'B. ruziziensis' (5.14 mum) and 9.48% thinner than 'B. decumbens' (3.58 mum). 'B. brizantha' cv. Marandu showed the lowest amount of lignin based on cell-wall fiber characteristics.