Modified Nano-Montmorillonite and Monensin Modulate In Vitro Ruminal Fermentation, Nutrient Degradability, and Methanogenesis Differently

Abstract

Two types of modified nano-montmorillonite (MNM) were developed by ion-exchange reactions using two different surfactants; sodium dodecyl sulfate (SDS) and cetyltrimethylammonium bromide (CETAB), to prepare MNM_SDS and MNM_CETAB, respectively. Both MNM types were on the nano-scale and had higher cation-exchange capacity values than NM clay. The MNM_CETAB had the highest zeta potential (-27 mV) compared with the other clays. Effects of MNM types on <i>in vitro</i> ruminal batch culture fermentation, nutrient degradability, and methane (CH₄) emission compared with monensin were evaluated <i>in vitro</i> using a semi-automatic gas production system. The experimental treatments were the control (0 supplementations), monensin (40 mg/kg DM), and NM (5 g NM/kg DM), and two levels of MNM_SDS and MNM_CETAB were supplemented at 0.05 (low) and 0.5 (high) g/kg DM to the control basal feed substrate. Among the experimental treatments, the high dose of both MNM types reduced (<i>p</i> < 0.01) CH₄ production and ammonia concentrations compared with the control, while only MNM_CETAB treatment tended to increase (<i>p</i> = 0.08) the truly degraded organic matter compared with monensin. All MNM treatments increased (<i>p</i> < 0.01) acetate molar proportions compared with monensin. The high MNM_CETAB increased (<i>p</i> < 0.01) the <i>in vitro</i> ruminal batch culture pH compared with the control and monensin. The MNM_CETAB supplemented at 0.5 g/kg DM is the most efficient additive to reduce CH₄ emission with the advantage of enhancing the <i>in vitro</i> nutrient degradability of the experimental feed substrate. These results indicated that MNM could modulate the <i>in vitro</i> ruminal fermentation pattern in a dose- and type-dependent manner.