Sodium hydroxide or urea pretreatment of acerola (Malpighia emarginata) fruit residue increases dry matter degradability and reduces methane production in in vitro rumen fermentation.

Abstract

The aim of this study was to evaluate the effect of adding different concentrations of either urea or NaOH in dehydrated acerola (Malpighia emarginata) fruit residue (DAFR) on chemical composition, in vitro rumen degradability, and gas and methane production. A completely randomized design was used with the following seven treatments: control, without chemical treatment, or pretreatment of DAFR with urea or NaOH at 20, 40, or 60g/kg dry matter (DM). DM degradability and gas and methane production of DAFR were evaluated by semi-automated in vitro gas production technique. DAFR treated with urea or NaOH at concentrations of 40 and 60g/kg DM decreased its neutral detergent fiber (P = 0.0115) and lignin (P < 0.0001) content, and this reduction was greater with the highest concentration (60g/kg DM). In all tested concentrations, urea and NAOH were effective to increase the DM effective degradability of DAFR compared with the control treatment, although treatments with a concentration of 60g/kg DM presented the highest values (P < 0.0001). Treatment of DAFR with NaOH or urea at 60g/kg DM promotes greater lignin solubilization and DM degradability and lower gas and methane production in in vitro rumen fermentation.