SUMMARY
Considering the new norms in feed quality checking (ANSVSA Order 51/2005 on the performance of the analytical methods and data interpretation), which are aligned to the European norms, the market for feeds implemented a checking system similar to the one for the food industry. These requirements stipulate that the laboratories for feed control must have validated methods for each sample assay. We therefore proposed to validate two chromatographic methods (HPLC and GC) for vitamin E and linolenic acid from the polyunsaturated fatty acids-enriched feeds for layers supplemented with 250 ppm vitamin E. The determined parameters were in agreement with SR EN ISO / CEI 17025:2005 as follows: exactness, reproducibility, sensitivity, accuracy, detection limit, quantification limit. We used for validation only certified reference materials and blanks, of analytical purity. We determined the incertitude for each validated method. We worked on two types of compound feeds for layers enriched in polyunsaturated fatty acids (I); with addition of flax seeds and with enriched linolenic acid (II). While the calculation of incertitude (10,62±0,44µg/g and 15,409±0,6µg/g for linolenic acid and 400±24 µg/g for vitamin E) shows that the methods range within admissible limits. The validated methods are proper for the determination of vitamin E and linolenic acid from feeds enriched in plant fat with a significant supplement of a-tocopherol.