Evaluation on digestible organic matter and metabolizable energy of oil palm frond silage-based total mixed ration supplemented with different enzyme levels using in vitro gas production technique

Abstract

In vitro gas production technique was applied to evaluate digestible organic matter (DOM) and metabolizable energy (ME) of oil palm frond (OPF) silage-based total mixed ration (TMR) supplemented with different levels of fibrolytic enzyme produced by Aspergillus spp. BCC 274 using rumen fluid from goats. Four levels of enzyme (0, 2, 4 and 6 g/kg DM of TMR) were tested in a completely randomized design (CRD). The results showed that soluble gas fraction (a) and rate of gas production (c) of OPF silage-based TMR was not significantly different among treatments (P>0.05). The OPF silage-based TMR supplemented with enzyme at 2, 4 and 6 g/kg DM were significantly higher in fermentation of insoluble fraction (b) (86.83, 81.67 and 82.28 ml, respectively, P>0.05) and potential of extent of gas production (d) (94.26, 90.93 and 90.37 ml, respectively, P>0.05) than the OPF silage-based TMR supplemented with enzyme at 0 g/kg DM (72.48 and 79.79 ml, respectively). In addition, the ME and DOM of OPF silage-based TMR supplemented with enzyme at 2 g/kg DM (2.72 Mcal/kg DM and 74.77%, respectively) were significantly higher (P<0.05) than those of the OPF silage-based TMR supplemented with enzyme at 0 g/kg DM (2.34 Mcal/kg DM and 65.23%, respectively). The results of this research indicated that the beneficial level of enzyme supplementation was at 2 g/kg DM of TMR.