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

Yosra Soltan,Mahmoud Elazab,Mohamed Sultan,Nesrein Hashem,Nourhan Hosny,Amr Morsy,Haneen Marey,Gomaa Abo El Lail,Nagwa El-Desoky,Elsayed Hafez,Sobhy Sallam,Ahmed Mahdy

doi:10.3390/ani11103005

Abstract

Simple SummaryNatural montmorillonite (NM) is the most common clay used as a feed additive in ruminant diets. Under normal pH conditions, it can adsorb hydrogen and may affect methane (CH4) formation; however, it possesses less efficiency than other clays. Due to NM’s negative charge flat surface and positive charge edges, its physicochemical properties can be modified by cationic or anionic surfactants. Therefore, two types of modified nano-montmorillonite (MNM) were developed by ion-exchange reactions using cationic and anionic surfactants. Comparisons were made with monensin as a rumen modulator to reduce CH4 emission from ruminants. The results indicated that the physicochemical properties of both MNM types were enhanced (e.g., cation-exchange capacity and zeta potential). All MNM clays and monensin successfully reduced rumen CH4 production and ammonia concentration; however, clay modified by cationic surfactant was more efficient than what was modified by anionic surfactant in modulating in vitro rumen fermentation propertiesTwo 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 MNMSDS and MNMCETAB, respectively. Both MNM types were on the nano-scale and had higher cation-exchange capacity values than NM clay. The MNMCETAB had the highest zeta potential (−27 mV) compared with the other clays. Effects of MNM types on in vitro ruminal batch culture fermentation, nutrient degradability, and methane (CH4) emission compared with monensin were evaluated in vitro 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 MNMSDS and MNMCETAB 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 (p < 0.01) CH4 production and ammonia concentrations compared with the control, while only MNMCETAB treatment tended to increase (p = 0.08) the truly degraded organic matter compared with monensin. All MNM treatments increased (p < 0.01) acetate molar proportions compared with monensin. The high MNMCETAB increased (p < 0.01) the in vitro ruminal batch culture pH compared with the control and monensin. The MNMCETAB supplemented at 0.5 g/kg DM is the most efficient additive to reduce CH4 emission with the advantage of enhancing the in vitro nutrient degradability of the experimental feed substrate. These results indicated that MNM could modulate the in vitro ruminal fermentation pattern in a dose- and type-dependent manner.

Highlights

Enteric fermentation is considered an actual cause of climate change and environmental pollution due to the emissions of greenhouse gases (e.g., methane (CH4 ) and carbon dioxide (CO2 )) [1]
Negligible variations in pH were detected among all clay products
Reductions in Gas Production (GP) and CH4 were consistent with enhancements in protozoal count and degradability of OM and NDF by MNM types, while this phenomenon did not appear after monensin treatment in the present study, in which CH4 inhibition by monensin was consistent with adverse effects on nutrient degradability and protozoal count. These results suggested that monensin had a different CH4 reduction mechanism from that of MNM

Summary

Introduction

Enteric fermentation is considered an actual cause of climate change and environmental pollution due to the emissions of greenhouse gases (e.g., methane (CH4 ) and carbon dioxide (CO2 )) [1]. The CH4 emission from ruminants represents a significant loss of dietary energy, which could be redirected towards valuable animal products [2]. Various rumen fermentation modifiers have been applied for ruminants to inhibit CH4 emission; the dietary antibiotic ionophores (e.g., sodium monensin) seem to be the most successful ones [3]. Ionophores are polyether antibiotics acting as inhibitors to deamination and H+ producing bacteria. They mainly disturb the bacterial cell wall membrane through ion exchange capacity,

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Discussion

Conclusion