Enhancement of Total Lipid Content/Composition in Non-GMO Alfalfa and Sainfoin for Improved Energy Density and Reduced Methane Emissions

Background

Adding moderate amounts of oil or fat to cattle feed can help lower methane emissions. This occurs because high-fat feeds are energy-dense, causing cows to eat slightly less and resulting in less methane (CH₄) being released. Also, fats act directly in the rumen by reducing the number of bacteria and protozoa involved in methane formation. However, supplementing fats in pasture-based diets can be costly and challenging to do. An alternative would be to develop forage plants that naturally contain high levels of fat. These would offer a practical, affordable way to cut methane emissions while maintaining livestock productivity by reducing intake and supporting the industry’s efforts toward environmental sustainability and profitability. 

Objectives

• Improve total shoot lipid content (TSLC) in sainfoin and alfalfa using ethyl methanesulfonate (EMS) mutagenesis. 
• Decipher the genetic basis of high TSLC mutagenized alfalfa genotype. 
• Increase the TSLC in alfalfa using CRISPR/Cas9 techniques. 

What they Did

This study used two approaches to develop forage plants with higher TSLC:  

1. A large population of alfalfa and sainfoin was developed by using a non-GMO chemical technique. These were studied for their lipid content. Those with higher content were selected and crossed to produce more generations of those varieties.  
2. The second approach involved modifying genes of a specific variety of alfalfa related to the fat metabolism of the plant. These plants were then crossed with elite lines to introduce these changes into high-performing ones.  

The project is continuing, with additional funding secured from the Alberta Funding Consortium to advance this work. 

What They Learned

The total lipid content of alfalfa and sainfoin was increased, given that the new lines contained 15–35% more fat than unmodified plants.  Other traits, such as biomass, digestibility, and nutrient composition, remained unchanged.  

Over 1,000 genes associated with lipid metabolism were identified that could be used in the future when looking at high‑ and low‑fat alfalfa. When genetically modified plants were crossed, the results were variable. Some plants grew normally, but others flowered later than usual. More work is needed to see if these techniques can reliably be used to change fat content without affecting other traits.  

What It Means

Results showed that it is possible to increase fat content in legumes such as alfalfa and sainfoin without negatively affecting their growth or nutritional quality. More research is needed to create new, commercially available, high-fat alfalfa varieties.