Influence of the growth stage of hemp (Cannabis sativa L.) on fatty acid content, chemical composition and gross energy.

Hemp (Cannabis sativa L.) has been studied to determine the fatty acid (FA) content, chemical composition, and gross energy (GE) of the plant during growth. Herbage samples were collected four times at progressive morphological stages from the mid vegetative to the early flower stage. The most abundant FA in the plant during these growth stages was ?-linolenic acid (C18:3 n-3) and it ranged between 48-54% of the total FA. The FA analyses disclosed quantitative differences between the plant stages. Palmitic acid (C16:0), oleic acid (C18:1 n-9), and linoleic acid (C18:2 n-6) decreased with increasing growth stage. There was a lack of ?-linolenic acid (C18:3n-6) at all stages of the hemp plant during growth. The dry matter, organic matter and acid detergent lignin content increased with increasing growth stage, while the ash and crude protein decreased from the mid vegetative stage to the shooting and late vegetative stage, respectively. Neutral detergent fibre increased from the first to the third stages and then decreased. GE was higher at the shooting stage than at the other stages.