Forage legumes rich in condensed tannins may increase n-3 fatty acid levels and sensory quality of lamb meat.

Abstract

Tannins intensively interact with rumen microbes, which is expected to have consequences for meat quality. Silages prepared from birdsfoot trefoil (BT), sainfoin (SF), alfalfa (AF) or red clover (RC) were fed alone to 48 lambs. The SF contained five times more condensed tannins than BT, the other tanniferous plant. Growth and carcass performance, but not general meat quality, was reduced with BT and SF compared to AF and RC. Lambs fed SF had half the skatole levels in the perirenal fat than AF-fed lambs. The longissimus thoracis et lumborum muscle of the SF-fed lambs, compared to RC and BT, had a lower intensity for 'livery' and 'sheepy' flavors but a stronger 'grassy' flavor. The intramuscular fat of BT- and SF-fed lambs contained less saturated and more polyunsaturated fatty acids, especially 20:4n-6, 20:3n-6, 20:5n-3 and 22:5n-3, with SF being more efficient than BT. The SF was most promising to increase beneficial fatty acids and to reduce skatole content in lamb meat.