324 Characterization and in Vitro Methane Inhibition of Aloe Vera and Moringa Oleifera Plant Extracts Encapsulated with Alginate Or Alginate-Chitosan Wall Materials Wall Materials
Authors: Ibrahim Taofik Adem , Imamu Abubeker Hassen 
Published: November 2023

Abstract
Although Aloe vera and Moringa oleifera plant extracts are known for their methane inhibition their potential has not been fully exploited in the feeding system of animals due to inconsistent results and loss of efficacy over time. Encapsulation of the plant extract and its bioactive compounds in particular with an inert material will assist to prolong the shelf life of the plant extract. Alginate is a good encapsulant (or a wall material) for encapsulation of plant extracts due to its biocompatibility and low density, among other factors. This study first evaluated A. vera and M. oleifera plant extracts encapsulated with alginate or aligante and chitosan in terms of microscopic morphological characteristics and particle density, and thereafter quantified the potential of encapsulated A. vera and M. oleifera plant extracts as dietary additive to inhibit in vitro methane production from Eragrostis curvula hay. An electron microscope scanning of the freeze-dried alginate or alginate encapsulated plant extracts of A. vera and M. oleifera revealed morphologically spongy and skin-like appearance while for chitosan a scatter particle distribution of different sizes with irregular shape were revealed (Fig. 1). A change in particle density was recorded for the encapsulated plant extracts products compared with the non-encapsulated product due to the inclusion of alginate or alginate-chitosan wall material. The particle density for the encapsulated products was ranging between 4.94 g/10mL (recorded in alginate) to 8.71 g/10mL (recorded in chitosan). During the in vitro gas production study, inclusion of both the encapsulated and non-encapsulated plant extract of A. vera or M. oleifera additives significantly (P &lt; 0.05) reduced methane emission compared with the control group. No adverse effect was observed due to the inclusion of the wall materials in terms of in vitro organic matter digestibility and total gas production (Fig. 2). However, the encapsulated A. vera plant extracts had resulted in a greater methane inhibition of 30.72% (for alginate-extract encapsulated) and 23.09% (for alginate-extract-chitosan encapsulated) against 17.55% reduction recorded for the raw plant extracts. Similarly, the encapsulated M. oleifera plant extracts inhibited methane by 30.02% (alginate-extract encapsulated) and 30.48% (alginate-extract-chitosan encapsulated) against 19.4% recorded for in M. oleifera raw plant extracts. It is revealed that alginate and/or chitosan also had methane reducing effect when tested as additives without the two plant extracts (Table 1,2). However, the differences in particle densities of the micro-particles from the encapsulated and non-encapsulated plant extract additives did not affect their methane inhibition (Fig. 3). Thus, the wall materials (alginate or alginate-chitosan) generally improved the in vitro methane inhibition of encapsulated plant extracts mainly by promoting the inhibition of methane without adverse effect on organic matter digestibility of substrates.