Volatile compound profile of ewe's milk and meat of their suckling lambs in relation to pasture vs. indoor feeding system

The present study investigated the volatile organic compound (VOC) profile in the milk of ewes grazing at pasture compared with ewes fed concentrate and hay and in the meat of suckling lambs. Fourteen Leccese pregnant ewes were divided into two groups: group P (n = 7) was allowed to graze a natural pasture from 08:00 to 18:00. Group S (n = 7) was housed in a pen and was offered vetch and oat hay (1.6 kg day−1 per head) and a commercial concentrate (0.5 kg day−1 per head). The male offspring lambs (n = 7 for the P group and n = 7 for the S group) received exclusively maternal milk. 45 days after lambing the ewes' milk was sampled, the lambs were slaughtered and the longissimus dorsi muscle was sampled. Both the milk and meat were subjected to SPME/GC/MS VOC analysis. The milk of the P ewes contained greater (P < 0.05) amounts of 2,3-octanedione and of alpha pinene and p-cymene than the milk from the S ewes. These compounds can be considered grass-feeding tracers. Conversely, we did not find significant differences in the accumulation of the VOC between the P and the S groups in the meat of the suckling lambs, though it was found that the meat of the P lambs contained higher (P < 0.05) levels of xylene, 1-pentanol, 1-hexanol and hexane 3-methyl than the S lambs.