Gas Production, Digestibility and Efficacy of Stored or Fresh Plant Extracts to Reduce Methane Production on Different Substrates

Abstract

Natural compounds such as plant secondary metabolites (PSM) can be used to replace antibiotic growth promoters as rumen modifiers. In this study, the effectiveness of stored and freshly extracted Aloe vera (AV), Azadirachta indica (AZ), Moringa oleifera (MO), Jatropha curcas (JA), Tithonia diversifolia (TD) and Carica papaya (CP) crude extract and monensin on in vitro gas and methane production, organic matter digestibility (IVOMD) and volatile fatty acids (VFA) were evaluated using a total mixed ration (TMR), lucerne or Eragrostis curvula substrates. Fresh extracts were processed from the same batch of frozen (−20 °C) plant material a few days before the trial while the stored extracts were extracted and stored at 4 °C for 12 months prior to the study. Extraction was done by solubilising 50 g freeze-dried plant material in 500 mL 100% methanol. Four mL of reconstituted 50 mg crude extract per 1000 mL distilled water was added per incubation vial, which already contained 400 mg substrate and in vitro fermentation, and gas production and IVOMD evaluation were carried out using standard procedures. Results showed that storing plant extracts for 12 months did not affect the activity or stability of metabolites present in the crude extracts, as shown by the lack of differences in total gas production (TGP) and methane produced between fresh or stored extracts across the substrates. In the TMR substrate, plant extracts increased IVOMD but did not affect TGP and methane production, whereas monensin did not have any effect. Plant extracts increased IVOMD of Eragrostis substrate and supressed methane production to a greater extent than monensin (p < 0.05). It can be concluded that storing plant extracts for up to 12 months did not compromise their efficacy. In addition, the use of 50 mg/kg of AV, AZ, MO, JA, TD and CP extract to a forage-based diet will reduce methane production while improving feed digestibility.

Haematology and Serum Biochemical Indices of Lambs Supplemented with Moringa oleifera, Jatropha curcas and Aloe vera Leaf Extract as Anti-Methanogenic Additives

“…Extracts solutions were administered at a dosage of 50 mg/kg of feed DM consumed while the actual dosage drenched to each animal was adjusted weekly using the previous week's feed intake. The 50 mg/kg dry matter intake (DMI) dose of extract was based on previous in vitro trials which established the effective dose at which the extracts reduced enteric methane [2,9,14]. Forty 4-month-old SAMM ram lambs with an average live weight of 28.8 ± 0.40 kg were blocked according to their body weight, and from each block randomly allocated into four dietary treatments which include (i) total mixed ration diet (TMR) + distilled water as a control, (ii) TMR + MO extract (50 mg/kg DMI), (iii) TMR + JC extract (50 mg/kg DMI) and, (iv) TMR + AV extract (50 mg/kg DMI).…”

“…However, while some of these PSMs are capable of binding to specific receptors in neurons, intestines, and other cells and exhibit favourable physiological effects [7], others may be antinutritional and exert toxic effects on animals consuming them, depending on the type of plant or parts, or amount consumed [6,8]. Even though the use of methanolic extracts of Moringa, Jatropha and Aloe vera has been validated in vitro [2,9], nevertheless, a great deal of consideration should be given to the impact of these 'natural alternatives' on the health of animals before being recommended for wider application. For example, the phorbol esters in Jatropha curcas at a concentration above 1.45 mg/kg body weight (BW) in ruminants were found to exert reduced performance, physiological toxic effects and cause eventual death [5,10,11].…”

“…Moreover, some structure of plants like the barks of trees are difficult to feed to animals but also contain valuable phytochemicals. Previous in vitro and in vivo trials have validated the anti-methanogenic effects of MO, JC and AV when used as dietary additives at 50 mg/kg DM of substrate [2,9,14], however, potential harmful effects on the animals were not established [14]. To justify this previous in vitro trial as well as make wider recommendations on the beneficial effects of extracts of MO, JC and AV in methane reduction and improvement in feed digestibility, there is a need to evaluate the potential impact of these medicinal plant extracts on the physiology of the animals.…”

Mitigation of Rumen Methane Emissions with Foliage and Pods of Tropical Trees

“…Conversely, studies on tropical plants such as G. sepium and E. cyclocarpum, and Y. schidigera, concluded that saponins did not reduce CH 4 production under in vitro conditions [77], and no significant effects were reported on ruminal methane production under in vivo conditions when Pelibuey sheep were fed with P. purpureum and supplemented with increasing levels of Yucca schidigera saponins (0, 1.5, 3.0, and 4.5 g/day) [78]. Akanmu et al [79] reported under in vitro conditions that the addition of 50 mg/kg of Moringa oleifera and Tithonia diversifolia extracts to a forage-based diet reduced CH 4 production without adverse effects on feed digestibility.…”

Effects of the Appropriate Addition of Antioxidants from Pinus densiflora and Mentha canadensis Extracts on Methane Emission and Rumen Fermentation

“…Aderao [ 43 ] recommended Acacia nilotica and Ziziphus nummularia leaves, which are rich in polyphenols, to be used as a feed as they reduce methane and improve green livestock production. Akanmu et al reported that the use of crude extract ( Azadirachta indica , Moringa oleifera , Jatropha curcas , Tithonia diversifolia and Carica papaya ) as feed decreased methane production and increased digestibility [ 44 ].…”