The Effects of Exogenous Fibrolytic Enzymes and a Ferulic Acid Esterase-Producing Inoculant Treatment on Digestibility and Conservation Characteristics of Corn Stover

Abstract

The objective of the current study was to determine the effects of a mixed bacterial inoculant possessing ferulic acid esterase (FAE) activity and exogenous fibrolytic enzyme (EFEs) products on the chemical composition, conservation characteristics and digestibility of corn stover.The moisture level of corn stover was adjusted to 40% with deionized water and then treated with deionized water (control), EFEs (10 U cellulase + 60 U xylanase units g(-1) of substrate dry matter) or EFEs + FAE inoculant (FAEI) (1.3x10(5) cfu g(-1) fresh forage). The treated stover was then incubated in laboratory mini-silos for 30 days. After the incubation period, the corn stover treated with both EFEs and EFEs + FAEI had a lower pH, ADF and NDF (P<0.001), and higher acetic acid and lactic acid (P<0.001) than the control stover. In addition, moulds and yeasts were inhibited in stover treated with EFEs + FAEI. The in vitro true dry matter digestibility (IVTDMD) and in vitro true neutral detergent digestibility (IVTNDFD) of the stover treated with EFEs and EFEs + FAEI were higher than for the control (P<0.001) but there was no significant difference between the EFEs and EFEs + FAEI treatments. From economical point of view, the best treatment was EFEs + FAEI. These results suggest that EFEs played a major role in enhancing the digestibility of corn stover, alone or in combination with FAEI. Moreover the use of EFEs + FAEI promoted a positive response in the conservation characteristics.