Yucca schidigera in ruminants
In ruminants, the steroidal saponins of yucca act on three levers of the rumen ecosystem: ammonia nitrogen, microbial protein synthesis and methanogenesis. Three issues at the heart of the efficiency and sustainability of livestock farming.
This page brings together what the scientific literature has measured: in vitro trials on rumen fluid, a trial in goats and the INRA review. Each figure is linked to its publication.
The rumen: a nitrogen and methane issue
In ruminants, the rumen ecosystem determines both the protein efficiency of the diet and the environmental footprint of livestock farming. As microbial digestion cannot be complete, it leads to nitrogen losses in urine or milk, and to a loss of energy in the form of methane, a greenhouse gas4.
The aim of nutritionists is therefore to steer the activity of the rumen ecosystem in order to optimise its functioning and reduce nitrogen and methane emissions. Plant extracts, natural alternatives to antibiotic growth promoters, are good candidates for regulating rumen function4.
Saponins are natural surfactants, made up of one or more hydrophilic chains (glycone) and a lipophilic core (aglycone). The latter is steroidal or triterpenoid in nature; Yucca schidigera is the best-known source of steroidal saponins4.
Four documented mechanisms in the rumen
Partial defaunation[2][4]
Through their detergent action, saponins lyse ciliate protozoa, whose membrane contains cholesterol, unlike that of bacteria. Fewer protozoa means less predation on bacteria and fewer associated methanogens.
Rumen ammonia buffer[2][4]
Ammonia is thought to be bound when its concentration is high, then released when it falls. Daily fluctuations are thus smoothed out and the microflora receives a steady supply; the liver saves the energy needed to convert excess ammonia into urea.
More microbial protein[2]
A greater share of the digested substrate is directed towards the synthesis of microbial mass, and a smaller share towards volatile fatty acids and gases. The microbial protein leaving the rumen increases.
Shift towards propionate[1]
Acetate falls, propionate rises and hydrogen production decreases. Less available H₂ means less substrate for methanogens: fermentation energy is better directed towards production.
A dose-dependent reduction in methane
Rumen fluid from dairy cows incubated for 6 h or 24 h with 1.2 to 3.2 g/L of sarsaponin (an extract of Yucca schidigera), on three substrates1. Choose a substrate and a duration.
The authors also observed, above 1.2 g/L, a decrease in the in vitro dry matter disappearance of the hay + concentrate after 24 h. These in vitro concentrations are higher than practical doses on farm; they serve to describe the mechanism, not to set a dose.
Fewer protozoa, less ammonia, more microbial protein
Yucca and quillaja saponin fractions (1.2 mg/mL) incubated for 24 h in an in vitro rumen fermentation system2.
Protozoa
Stronger effect on the diet with concentrate.
Ammonia
Purified yucca saponins give the largest decrease, about 30%.
Microbial protein synthesis
Confirmed by ¹⁵N incorporation and the measurement of microbial purines.
According to the authors, saponins partition digested nutrients towards microbial mass rather than towards volatile fatty acids and gases: the true degradability of the hay is maintained or improved, and gas production is reduced. Their inclusion in diets, particularly forage-based diets, could thus increase microbial yield and reduce CO₂ and CH₄ emissions2.
Making better use of a poor-quality urea-treated forage
Urea-treated maize stover (72 g/kg) was supplemented with Yucca schidigera powder at 0, 90, 120 or 160 mg/kg, then fed with legume leaves (Calliandra calothyrsus) to goats, in a 4 × 4 Latin square design3.
As the yucca dose increases, the proportion of urea nitrogen retained as ammonia fixed in the forage rises, as does the protein content. Intake, weight gain and the digestibility of DM, CP, crude fibre, OM and energy are significantly higher than with the control diets (P < 0.05). The author concludes that yucca has potential to trap ammonia nitrogen and improve the feeding value of poor-quality forages3.
| Yucca (mg/kg) | 0 | 90 | 120 | 160 |
|---|---|---|---|---|
| Urea nitrogen fixed in the forage% of N supplied | 51.8 | 60.6 | 66.3 | 84.0 |
| CP of the treated forage% DM | 15.4 | 16.6 | 17.6 | 20.7 |
| Digestible CPg/kg DM | 10.16 | 11.06 | 11.54 | 14.24 |
| Metabolisable energyMJ/kg DM | 6.45 | 8.09 | 8.51 | 8.64 |
Anglo-Nubian × Fijian local goats, 26.9 ± 3.4 kg. ME: metabolisable energy; CP: crude protein.
What the analysis of in vivo trials shows
INRA reanalysed 29 in vivo trials from the review by Patra and Saxena, taking into account the saponin dose and the forage / concentrate ratio of the diet4.
Why ammonia falls
Four explanations coexist: urease inhibition, binding of the glycone fraction to ammonia, reduced bacterial lysis, and inhibition of proteolytic and deamination activities4.
Why methane falls
Some methanogenic archaea live in association with protozoa: their suppression partly explains the decrease in CH₄, a result very often observed in vitro and in vivo, with a dose-dependent effect4.
Why responses vary
Some bacteria deglycosylate and inactivate yucca saponins; others adapt during prolonged supplementation. In vivo effects are therefore less clear-cut than in vitro, and long-term trials are still needed4.
As regards product quality, a dose of 60 g/day of yucca saponins in dairy cows causes only a minor change in the milk fatty acid profile4.
Our Yucca schidigera range, powder or liquid
In ruminants, the powder form is incorporated into the concentrate or the mineral; the liquid form is applied to the mixed ration. The choice depends on the feeding equipment and on herd management. Recommended doses are given in the technical data sheet.
Yucca and ruminants: your questions
Do yucca saponins really reduce methane?
In vitro, yes: with sarsaponin, Lila et al. (2003) measured up to 60% less methane, in a dose-dependent manner. In vivo, the reduction is frequently observed, but its extent varies with the dose, the diet and the adaptation of the microflora. It must therefore be validated in each farming context.
Does yucca inhibit urease?
Urease inhibition is one of the mechanisms put forward. Makkar et al. (1998) point out, however, that it appears unlikely in vivo. The binding of ammonia to saponins and their glycosylated compounds, together with partial defaunation, are the best-supported explanations.
Does the effect persist over time?
Some rumen bacteria can degrade yucca saponins, while others can adapt during prolonged supplementation. The INRA review (2014) recommends long-term in vivo trials. Monitoring and the supplementation strategy are a matter for technical support.
At what dose should yucca be included?
The doses studied in vitro exceed practical doses. In the INRA in vivo review, effects appear above 0.13 g/kg DM of saponins, with a favourable range between 0.2 and 8 g/kg DM. Our recommendations for the Yucca Schidigera range, powder and liquid, are given in the technical data sheet.
Scientific literature
- Lila Z.A., Mohammed N., Kanda S., Kamada T., Itabashi H. (2003). Effect of sarsaponin on ruminal fermentation with particular reference to methane production in vitro. Journal of Dairy Science, 86, 3330-3336.
- Makkar H.P.S., Sen S., Blümmel M., Becker K. (1998). Effects of fractions containing saponins from Yucca schidigera, Quillaja saponaria, and Acacia auriculoformis on rumen fermentation. Journal of Agricultural and Food Chemistry, 46(10), 4324-4328.
- Aregheore E.M. Effect of Yucca schidigera saponin on the nutritive value of urea-ammoniated maize stover and its feeding value when supplemented with forage legume (Calliandra calothyrsus) for goats. University of the South Pacific; published online on 9 June 2004 (journal and pagination to be completed).
- Bayourthe C., Ali-Haimoud-Lekhal D. (2014). Les extraits de plantes chez le ruminant : effets sur les fermentations dans le rumen et la qualité lipidique des produits animaux. INRA Productions Animales, 27(4), 317-327.
- Wallace R.J., Arthaud L., Newbold C.J. (1994). Influence of Yucca schidigera extract on ruminal ammonia concentrations and ruminal microorganisms. Applied and Environmental Microbiology, 60(6), 1762-1767.
- Cheeke P.R. (2000). Actual and potential applications of Yucca schidigera and Quillaja saponaria saponins in human and animal nutrition. Journal of Animal Science, 77(E-Suppl.), 1-10.
- Francis G., Kerem Z., Makkar H.P.S., Becker K. (2002). The biological action of saponins in animal systems: a review. British Journal of Nutrition, 88(6), 587-605.
Data taken from scientific publications (in vitro trials and a trial in small ruminants), presented for technical information purposes. They do not constitute results of Actifeed trials or product claims.