FRACIONAMENTO E CINÉTICA DA FERMENTAÇÃO RUMINAL in vitro DOS CARBOIDRATOS DE CINCO VARIEDADES DE CANA-DE-AÇÚCAR

Abstract

The objective of this study was to determine the chemical composition, the carbohydrates fractionation and the kinetics of in vitro ruminal fermentation of fibrous and non-fibrous carbohydrates of five sugarcane varieties. Variety SP79-1011 presented the highest value of total digestible nutrients (65.9%), followed by the varieties Java, RB72454, SP80-1842 and RB765418. For the accumulated gas in the dry matter, 48 and 96 horas of in vitro incubation were higher for the variety SP79-1011, showing significant difference in comparison with the varieties RB765418, RB72454 and SP80-1842, excepting the variety Java that did not show any difference in relation the first one. The dry matter partitioning factor decreased with the incubation time and there was no difference among the evaluated varieties. The characteristics of the production cycle influenced the in vitro ruminal fermentation of the evaluated varieties, being the varieties of precocious cycle (SP80-1842 and RB765418) the ones with the worst results. Amongst the varieties tested, SP79-1011 and Java presented the best results of gas production kinetics and total digestible nutrients