Production of lamb with poly-unsaturated depot fats (from feeding a dietary supplement of formaldehyde-treated ground sunflower seed)

Abstract

Abstract Eight Coopworth and eight Poll Dorset ewe lambs were used in two experiments respectively to determine how quickly the animals adapted to feedlot from grass pasture, and warmed to being fed a supplement of ground sunflower seed treated with formaldehyde so that the oil (70% linoleic acid) resisted biohydrogenation in the rumen. It was found that the level of linoleic acid in the perirenal fat of Coopworth lambs increased from 3 to 14% in a period of 40 days when they consumed an average of 100 g lipid/head daily and that of the Poll Dorset lambs increased from 4 to 25% in 30 days. Coopworths were fed 60% effectively protected supplement and Poll Dorsets 80% protected. Tasting tests showed that meat containing elevated levels of linoleic acid had a bland, pork-like flavour and a sweet, lingering odour-note on cooking. Only at the highest levels of poly-unsaturation ( > 20 %) did the meat have an oily taste; this was particularly apparent with the hot joint.