Omega-3 Purlsane Eggs
In this project, we will develop key elements of a Purslane – laying hen system for production of high quality omega-3 fatty acids important in human nutrition. We will determine the potential yield of α-linolenic acid (ALA), an omega-3 fatty acid, when Purslane is grown as a crop or forage and define optimal agronomic conditions for producing ALA in Purslane and DHA in eggs. Furthermore, using information from this research, we will assess the economic viability of implementing the system on a local, small farm scale.
1. Determine the variation in ALA omega-3 fatty acids in Purslane acquired from different sources and how best to conserve ALA in processing.
Purslane seeds will be collected from fields in the Coastal Plains, Piedmont, and Mountain regions of NC and purchased from commercial sources. Plants will be grown under favorable agronomic conditions in field plots. Leaf tissue samples and seeds will be analyzed when fresh and after drying at various temperatures to determine whether omega-3 levels differ and whether levels are affected by drying and heat.
2. Determine alterations in ALA content in Purslane plants subjected to environmental stress.
Plants from a selection of seed sources will be grown under field, greenhouse, and growth chamber conditions. Treatments will include water availability, fertility level, photoperiod, time of planting, and temperature. Changes in biomass production and omega-3 concentrations will be determined.
3. Evaluate the potential for Purslane inclusion into the poultry diet and the effects of Purslane on DHA omega-3 levels in eggs.
Preliminary tests will determine hen preference for fresh Purslane compared to conventional feed. Then, the nutritional acceptability of processed Purslane inclusion into feed at various concentrations would be tested. Hen weight, egg production, omega-3 contents, and cholesterol levels will be analyzed, and a conversion efficiency value calculated.
4. Examine the effects of Purslane inclusion in forage rotation on egg production and DHA accumulation in eggs.
Forage plots with either Purslane or grass will be established and divided in rotational paddocks. Hens will be periodically moved through the paddocks and provided with additional conventional feed to account for 80% of needed calories. After 45 days, hen weight, egg production, and egg fatty acid profile will be analyzed.
5. Determine the economic feasibility of the proposed production system.
An economic analysis will be conducted and a business plan will be developed to assess the potential profitability of the Purslane-laying hen system.
Over the initial five months of the project, we have conducted preliminary studies with Purslane. Fourteen commercial Portulaca oleracea and two locally collected Portulaca rubricaulis seed sources or ‘varieties’ were grown, harvested, and analyzed. Fatty acid contents, measured using gas chromatography, showed 26-29% of the fatty acids in Purslane seeds were ALA, compared to 6-8% of the fatty acids in soybean seed checks. This is a much higher ALA percentage than all commercial oils, and it approaches levels in flaxseed. Purslane leaves contained 60-67% ALA as a percentage of total fatty acids, compared to 52% in soybean leaves. As a proportion of dry weight, one ‘variety’ had over twice the amount of ALA in its leaves as soybean and considerable phenotypic variation was seen among seed sources, suggesting good potential for selection of genetically superior lines.
Currently, we are setting up experiments in the NCSU Phytotron with controlled temperature and watering treatments to examine Purslane’s response to environmental stress. The temperature study will examine how temperature affects growth and reproduction and the fatty acid profile of seeds and leaves. The drought study will examine how well Purslane can withstand and recover from drought.
We plan to conduct field studies this summer to test how seeding density, nutrition, and multiple harvests affect total biomass production and ALA production in leaves and seeds. Next summer, free range chickens will be incorporated into field studies to determine the effects of Purslane foraging on DHA concentration in eggs.
Impacts and Contributions/Outcomes
Using purslane and chickens to produce omega-3’s would support local economies, minimize fossil fuel consumption and environmental damage, and create a value added, organic, local product for farmers. It would contribute to integration within small farm operations, as crop and poultry operations would be directly linked, and the dietary product of the system would contribute positively to human health. A research project that aids in development of this type of system is thus entirely aligned with the economical, social, and environmental goals of sustainable agriculture.
Production of purslane eggs could impart significant economic returns to farmers. Costs of purslane production should be low since purslane has adapted to and grows prolifically in the Southeast. Eggs produced in this system would have added market value both from the high DHA omega-3 content and from local, sustainable production practices. Supplementation with the inexpensive ALA in purslane will be particularly beneficial for small farms that currently have limited access in the DHA market due to high costs of commercial supplements. The system would also contribute to farm diversification, in addition to the omega-3 eggs. Purslane not used for on-farm egg production could be marketed locally to other poultry farmers or sold directly to restaurants and consumers as a nutritious salad green, as it is consumed in many parts of the world.
Incorporation of purslane into egg production has many potential social benefits. Economically, the system will support family farms and rural communities. Purslane eggs will have the additional health benefits of providing a nutritious, culturally accepted food to consumers and improving public health. Evidence supports that free-range purslane eggs, in addition to having a higher DHA content than conventional eggs, are also lower in saturated fat and cholesterol (Simopoulos 1989, Zotte 2005). The improved eggs have the potential to improve health and quality of life for everyone.
Purslane eggs could also provide an environmentally sound alternative to current DHA sources. Since purslane grows as a weed, it is a safe assumption that it has relatively low requirements of energetically wasteful or polluting outside inputs. In fact, using poultry manure to fertilize purslane plots would partially close the nutrient cycle. In this study, we will attempt to maximize efficiency of ALA production through phenotypic selection and manipulation of growing conditions. Understanding and implementing efficient production practices minimizes the number of acres in production and prevents wasting water, fertilizer, or other resources. In contrast to importation of flax or fish oil for feed supplements, local omega-3 production allows for conservation of non-renewable resources such as petroleum. Finally, obtaining high quality DHA from eggs could reduce dependency on over-used fisheries and provide omega-3’s for a growing human population.
NCSU Crop Science Department
4411 Williams Hall
Campus Box 7620
Raleigh, NC 27695
Office Phone: 9195153660