Chemical composition, organic matter digestibility and fatty acid content of linseed (Linum usitatissimum L.) harvested at five stages of growth
2008
Peiretti, Pier Giorgio | Meineri, Giorgia
BAKGROUND: The quality of forages changes according to the morphological stage and it is important to define the nutritive characteristics and fatty acid (FA) content of the crop during growth. That allows a choice of cutting time in order to optimise the uilisation of the forages and to identify new sources of polyunsatured fatty acids (PUFAs) for ruminants. Our aim was to study changes in the chemical composition, in vitro organic matter digestibility, gross energy, and FA content, of linseed (Linum usitatissimum L.) samples collected from the stem extension to the mature seed stage.RESULTS: The development of linseed quality during growth is characterised by a progressive increase in the fibrous fractions and a decrease in crude protein, ether extract, ash, and in vitro organic matter digestibility (IVOMD). The FA profiles in the plant were characterised by four dominant FAs: palmitic acid (PA, 16:0), stearic acid (SA, 18:0), linoleic acid (LA, 18:2n-6) and α-linolenic acid (ALA, 18:3n-3). PA, SA and LA increased from the visible bud stage to mature seed stage, while ALA decreased, consequently the n-6/n-3 polyunsaturated FA ratio of the plant increased during growth.CONCLUSION: The chemical composition and FA profile of linseed is closely connected to the development of the plant. Forage with a good nutritive value and with a content of unsaturated FA that is suitable for herbivorous feeding is still obtained by harvesting green linseed at the brown capsule stage.
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