Influence of Azadirachta indica and Cnidoscolus angustidens Dietary Extracts on Equine Fecal Greenhouse Gas Emissions.
Authors: Alvarado Tonantzin Díaz, Elghandour Mona M M Y, Ekanem Nsikan Joseph, Alcala-Canto Yazmin, Velázquez Alejandro Esquivel, Pacheco Edson Brodeli Figueroa, Purba Rayudika Aprilia Patindra, Salem Abdelfattah Z M
Journal: Journal of equine veterinary science
Summary
# Editorial Summary: Plant Extracts as Methane Mitigation in Equine Hindgut Fermentation Neem (*Azadirachta indica*) and pigeon pea (*Cnidoscolus angustidens*) have demonstrated antimicrobial and antioxidant properties in livestock, yet their application to equine digestive health remains underexplored; this in vitro investigation sought to determine whether aqueous extracts of these plants could suppress greenhouse gas production in equine faecal fermentation. Using a 48-hour incubation model with horse faeces and a nutrient-dense substrate, researchers assessed gas emissions at four extract dosages (0–1.8 mL) applied individually and in combination, measuring methane, carbon monoxide, hydrogen sulphide, and short-chain fatty acid profiles. Methane production declined substantially in a dose-dependent manner—by up to 54.54% with intact substrate and 61.82% when substrate was pre-degraded—whilst hydrogen sulphide reductions ranged from 18.37% to 67.35%, with the combined extract proving most effective at higher concentrations. Critically, these reductions occurred without suppressing overall fermentation activity, as pH remained stable and short-chain fatty acid concentrations improved, though dry matter digestibility and metabolizable energy decreased marginally. For practitioners, these findings suggest potential value in botanical feed additives for reducing environmental emissions and potentially improving hindgut health markers, though in vivo confirmation is essential before recommending these extracts as practical nutritional interventions in working or competition horses.
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Practical Takeaways
- •These plant extracts show promise as potential feed additives to reduce environmentally harmful greenhouse gas emissions from horses, though in vivo efficacy in living animals remains to be demonstrated
- •The dose-dependent response suggests optimal dosing protocols may be developed for practical farm application if results translate to live horse studies
- •Further research is needed to establish whether these benefits manifest in horses under field conditions and at what cost-benefit threshold they become economically viable for equine operations
Key Findings
- •Azadirachta indica, Cnidoscolus angustidens, and their combination reduced methane production by 4.41% to 61.82% in a dose-dependent manner
- •Plant extracts reduced hydrogen sulfide production by 8.51% to 67.35% across both incubated and degraded substrates
- •Short-chain fatty acid concentration improved significantly with plant extract treatment while pH remained within normal range
- •Reductions in greenhouse gas production occurred without deleterious effects on fecal fermentation activity