Yucca schidigera in aquaculture, in feed and in water
In aquaculture, yucca can be supplied in two ways. Incorporated into feed, it acts on the nitrogen metabolism of the fish; added to the rearing water, it tackles dissolved ammonia directly. This page brings together the published trials in fish and shrimp.
Ammonia, the primary limiting factor in intensive farming
The higher the stocking density, the more nitrogen accumulates in the water: faeces, uneaten feed and organic matter release ammonia. In its toxic form, it damages the gills, disrupts osmoregulation and weakens the immune system, resulting in reduced appetite, slower growth and mortalities.
Water exchange, oxygenation, biological filtration or suspending feeding remain the conventional levers. Yucca is being studied as a natural complement, in open ponds and recirculating systems alike, and in combination with biofloc systems.
What proportion of ammonia is toxic?
Total ammonia nitrogen is divided between the ammonium ion (NH₄⁺), which has low toxicity, and un-ionised ammonia (NH₃), which is toxic. This distribution depends on the pH and temperature of the water. Adjust both to see the toxic fraction.
That is 6.1 times more than at pH 7 at the same temperature. For 2 mg/L of total ammonia nitrogen, this represents 0.07 mg/L of NH₃.
Link with yucca: in European sea bass, the extract added to the water lowered the pH, which probably reduces the NH₃ fraction [4][3]. Calculation based on Emerson et al., 1975 [16], in freshwater.
Two delivery routes, two sets of results
Incorporated into feed, yucca acts on nitrogen metabolism: less nitrogen and ammonia released by the fish, and often better growth and better feed efficiency. Doses are expressed in mg or as a % of the feed.
Added to the rearing water, yucca acts directly on the dissolved ammonia arising from excreta and uneaten feed. Doses are expressed in mg per litre or in g per m³ of water.
In catfish, less nitrogen released
Pangasius
Juveniles of 1.78 g, 15 fish per 80 L tank, 3 replicates, freshwater recirculating system at 29.7 °C, 12 weeks. Fishmeal-based feed, with 0 to 0.15% yucca extract.
Channel catfish
Post-yolk-sac fry and juveniles fed for 12 weeks with 0, 0.5 or 1.0 g of yucca extract per kg of feed, agar-coated for the fry. Hybrid tilapia was also studied.
What happens in the water, and in the fish
The review by Paray et al. (2021) distinguishes between a direct effect on water quality and indirect effects on growth and immunity.
- In the water Ammonia binding
- The steroidal saponin fractions, which are surfactants, bind to ammonia through their glycosidic components. A conversion of ammonia into nitrite and nitrate has also been suggested.[3][10]
- In the water pH reduction
- In European sea bass, the extract added to the water lowered the pH. And the toxic fraction of ammonia decreases as the pH falls (see the simulator).[4]
- In the fish Nitrogen metabolism
- Less faecal nitrogen and ammonia excreted, more protein retained: the fish spends less energy balancing its protein metabolism.[1][2][3]
- In the fish Intestinal immunity
- Increased lysozyme and complement, decreased pro-inflammatory cytokines (TNF-α, IL-1β, IL-6); better resistance to certain pathogenic bacteria.[5][8]
- In the fish Antioxidant defences
- Increased SOD, CAT and GPx activities and decreased malondialdehyde. The phenolic compounds in yucca, including resveratrol, are thought to contribute to this.[5][6]
- In the system Ponds, recirculating systems and biofloc
- The results apply to open ponds and closed systems alike; yucca is presented as complementary to biofloc technology.[3]
A window of use to be respected
Saponins are active at low doses and harmful at high doses. According to the review by Paray et al., moderate levels promote growth, whereas high levels can cause enteritis. The dose also depends on the species and on the saponin content of the product.
Favourable
No measurable effect
Unfavourable
The same order of dose can be favourable in one species and unfavourable in another: 1.5 g/kg improves growth in pangasius, whereas 1.1 g/kg reduces it in channel catfish. Hence the importance of validating the dose by species and by product.
Yucca Schidigera, powder or liquid
The powder form is incorporated into feed; the liquid form disperses rapidly in the rearing water. The choice depends on the species, the system (pond, recirculating system, biofloc) and the logistics of the farm. The quality of a product is judged by its saponin content.
Yucca in aquaculture
Should it be supplied in the feed or in the water?
Both routes are documented. In feed, yucca acts mainly on the nitrogen metabolism and growth of the fish; in water, it acts directly on dissolved ammonia. The choice depends on the species, the rearing system and its logistics.
Can it replace water exchange or oxygenation?
No. Yucca is a complement to the conventional levers (water exchange, oxygenation, biological filtration), not a substitute. It helps to control ammonia without removing the need for good water management.
Can a large amount be used to get results faster?
No. Saponins become harmful at high doses: in water, 1,000 ppm of yucca saponins killed carp within 18 hours, and high levels in feed can cause enteritis. The published effective doses are much lower: a few tenths of a mg per litre of water, or of the order of one gram per kg of feed.
Is it compatible with a biofloc system?
The review by Paray et al. (2021) presents yucca as complementary to biofloc technology. Monitoring of water parameters is still recommended when it is introduced.
How can two yucca-based products be compared?
By their saponin content, which drives the effect on ammonia, rather than by their yucca content. Actifeed guarantees a consistent content from one batch to the next and specifies the doses for its range in the technical data sheet.
Scientific literature
- Kelly A.M., Kohler C.C. (2003). Effects of Yucca shidigera extract on growth, nitrogen retention, ammonia excretion, and toxicity in channel catfish Ictalurus punctatus and hybrid tilapia Oreochromis mossambicus × O. niloticus. Journal of the World Aquaculture Society, 34(2), 156-161. doi:10.1111/j.1749-7345.2003.tb00052.x
- Güroy B., Mantoğlu S., Kayalı S., Şahin İ. (2014). Effect of dietary Yucca schidigera extract on growth, total ammonia–nitrogen excretion and haematological parameters of juvenile striped catfish Pangasianodon hypophthalmus. Aquaculture Research, 45(4), 647-654. doi:10.1111/are.12001
- Paray B.A., El-Basuini M.F., Alagawany M., Albeshr M.F., Farah M.A., Dawood M.A.O. (2021). Yucca schidigera usage for healthy aquatic animals: potential roles for sustainability. Animals, 11(1), 93. doi:10.3390/ani11010093
- Fayed W.M., Khalil R.H., Sallam G.R., Mansour A.T., Elkhayat B.K., Omar E.A. (2019). Estimating the effective level of Yucca schidigera extract for improvement of the survival, haematological parameters, immunological responses and water quality of European seabass juveniles (Dicentrarchus labrax). Aquaculture Reports, 15, 100208.
- Wang L. et al. (2020). Effect of Yucca schidigera extract on the growth performance, intestinal antioxidant status, immune response, and tight junctions of mirror carp (Cyprinus carpio). Fish & Shellfish Immunology, 103, 211-219.
- Abdel-Tawwab M., Mounes H.A., Shady S.H., Ahmed K.M. (2021). Effects of yucca, Yucca schidigera, extract and/or yeast, Saccharomyces cerevisiae, as water additives on growth, biochemical, and antioxidants/oxidant biomarkers of Nile tilapia, Oreochromis niloticus. Aquaculture, 533, 736122.
- Yang Q.-H., Tan B.-P., Dong X.-H., Chi S.-Y., Liu H.-Y. (2015). Effects of different levels of Yucca schidigera extract on the growth and nonspecific immunity of Pacific white shrimp (Litopenaeus vannamei) and on culture water quality. Aquaculture, 439, 39-44.
- Njagi G.W., Lee S., Won S., Hong J., Bai S.C., Hamidoghli A. (2017). Effects of dietary Yucca meal on growth, haematology, non-specific immune responses and disease resistance of juvenile Nile tilapia, Oreochromis niloticus. Aquaculture Research, 48, 4399-4408.
- Tidwell J.H., Webster C.D., Clark J.A., Yancey D.H. (1992). Effects of Yucca shidigera extract on water quality and fish growth in recirculating-water aquaculture systems. Progressive Fish-Culturist, 54, 196-201.
- Santacruz-Reyes R.A., Chien Y.-H. (2010). Ammonia reduction in seawater by Yucca schidigera extract: efficacy analysis and empirical modelling. Aquaculture Research, 41, 1221-1228.
- Hernández Acosta M. et al. (2016). The effects of Yucca schidigera and Quillaja saponaria on growth performance and enzymes activities of juvenile shrimp Litopenaeus vannamei cultured in low salinity water. Latin American Journal of Aquatic Research, 44(1), 121-128.
- Angeles I.P. Jr., Gallego L.M., Navarro M.A.M., Chien Y.-H. (2017). Dietary effects of Quillaja saponaria and Yucca schidigera extract on rearing performance of Nile tilapia Oreochromis niloticus and its antioxidant capacity and metabolic response following hypoxic stress. International Journal of Agricultural Technology, 13, 2249-2266.
- Yeh S.-P., Liu C.-H., Sung T.-G., Lee P.-P., Cheng W. (2006). Effect of saponin on hematological and immunological parameters of the giant freshwater prawn, Macrobrachium rosenbergii. Aquaculture, 261, 1432-1439.
- Elkhayat B., Mansour A., Fayed W., Omar E., Nour A.A. (2019). The effect of Yucca schidigera extract dietary supplementation on growth performance, feed and protein utilization of European seabass, Dicentrarchus labrax, fingerlings. Egyptian Journal of Aquaculture, 9, 15-31.
- El-Keredy M.S.A., Naena N.A.A. (2020). Yucca plant as treatment for Pseudomonas aeruginosa infection in Nile tilapia farms with emphasis on its effect on growth performance. Alexandria Journal of Veterinary Sciences, 66, 64.
- Emerson K., Russo R.C., Lund R.E., Thurston R.V. (1975). Aqueous ammonia equilibrium calculations: effect of pH and temperature. Journal of the Fisheries Research Board of Canada, 32(12), 2379-2383.
- Bae J. et al. (2020). Evaluation of seven different functional feed additives in a low fish meal diet for olive flounder, Paralichthys olivaceus. Aquaculture, 525, 735333.