Chemical composition, organic matter digestibility and fatty acid content of evening primrose (Oenothera paradoxa) during its growth cycle

Evening primrose (Oenothera paradoxa) was studied to determine its chemical composition, in vitro organic matter digestibility (IVOMD), and fatty acid (FA) content during growth. Herbage samples were collected five times at progressive morphological stages from the rosette to the early seed-pod stage. The dry matter (DM), organic matter (OM), neutral detergent fibre (NDF), acid detergent fibre (ADF), and acid detergent lignin (ADL) increased with increasing growth stage, while the crude protein (CP) and ash decreased with increasing stage. Ether extract (EE) decreased only to the bud stage and gross energy (GE) increased to the bud stage. The nutritive quality of evening primrose decreased with advancing stages. The fatty acid profile in the plant during growth differs from the oil in the seeds, with α-linolenic (C18:3n−3), linoleic (C18:2n−6) and palmitic (C16:0) acids dominant in the total fatty acid content of the plant. There was a lack of γ-linolenic acid (C18:3n−6) at all stages of evening primrose plant during growth.