Determination of non-esterified fatty acids (NEFA)

The measurement of non-esterified fatty acids (NEFAs) allows for the evaluation of the free fraction of lipids circulating in a biological or food matrix. These free fatty acids, released from triglycerides by lipolysis, represent a key metabolic indicator of energy reserve mobilization and nutritional status in animals. In animal health, their analysis is essential for metabolic monitoring, the prevention of energy disorders, and the formulation of feeds enriched with specific fatty acids.

The analysis is based on gas chromatography with flame ionization detection (GC-FID) or gas chromatography coupled with mass spectrometry (GC-MS), offering precise quantification and excellent resolution of the different fatty acids present.

Principle and operation of the method

The samples (oils, lipid extracts, animal sera, enriched formulations) undergo specific extraction of free fatty acids using organic solvents.
The isolated lipid fraction is then injected into the chromatographic system to separate the fatty acids according to their volatility and molecular structure.

• GC -FID allows direct quantification through a response proportional to carbon content.
• GC -MS offers fine structural identification, useful for distinguishing between isomeric or polyunsaturated fatty acids.

The results are expressed as a percentage or as an absolute concentration (mg/L or µmol/L), depending on the matrix and the need for the study.

Analytical performance and related analyses

The GC-FID and GC-MS methods ensure:

• high sensitivity for detecting free fatty acids at very low concentrations,
• excellent reproducibility ,
• and a precise identification of saturated, monounsaturated and polyunsaturated fatty acids.

This measurement can be supplemented by other lipid analyses to obtain a complete fat profile:

• the determination of fatty acid methyl esters (FAME),
• the dosage of total fatty acids ,
• or even the measurement of triglycerides .

These combined services allow for the evaluation of overall lipid composition and a better understanding of metabolic processes related to diet and animal physiology.

Applications and areas of use

The measurement of NEFAs is particularly relevant in the following areas:

• Animal health : monitoring of energy parameters in cattle, sheep or pigs, particularly during the transition period or in case of nutritional imbalance.
• Formulation of fortified foods : control of the content of functional fatty acids in rations, oils or nutritional additives.
• Metabolic research : study of variations in lipid profile in relation to performance, oxidative stress or reproduction.
• Quality control of lipid extracts : verification of the purity and stability of animal or vegetable oils.

These analyses contribute to a better understanding of energy mechanisms and to the improvement of nutritional strategies in livestock farming.

The advantages of the YesWeLab service

YesWeLab collaborates with a network of partner laboratories specializing in lipid and metabolic analyses, accredited to ISO 17025 and COFRAC. Each sample is directed to the most suitable laboratory according to the matrix, method, and desired precision.

Thanks to its digital analysis platform, YesWeLab simplifies service management: quote requests, sample tracking, and online results delivery. Since 2020, numerous players in the animal health sector, feed manufacturers, and research laboratories have trusted us for their lipid analyses.

For any specific needs in the measurement of non-esterified fatty acids, contact our scientific team for personalized support and a customized quote.