Fatty acid oxidation of meat from lambs fed diets supplemented with extruded linseed and olive cake.

The use of linseed in the diet increases alfa-linolenic acid (LNA), n-3 PUFA and conjugated linoleic acid (CLA) content in the meat fat. However, feeding animal with linseed potentially increases the susceptibility of the meat fat to oxidation, favoring off-flavor production. The use of antioxidants in the diet may be a solution to prevent these problems. At this aim, in the present study, olive cake as source of antioxidant substances was used as alternative to Vitamin E supplementation in lamb feeding. The experiment was conducted on 32 Appenninica lambs, equally assigned to 4 experimental groups: control (C), linseed (L), olive cake (O) and olive cake + linseed (OL). Samples of longissimus dorsi muscle were stored at 4°C and analysis for antioxidant content and lipid oxidation were repeated at 0, 4, 7 and 11 days during the storage period. Antioxidant (tocopherols and retinol) content was analyzed by HPLC. Lipid oxidation was determined by 2-thiobarbituric acid reactive substances (TBARS) analysis and cholesterol oxidation product analysis. The use of olive cake in the diet increased the meat antioxidant content (+52%), particularly tocopherols level, which remains higher after 11 days of storage. The higher antioxidant level in animals fed with O and OL diet resulted in a greater protection of meat against lipid oxidation. At time 0 the amount of TBARS in lamb meat was not different across diets. After 11 days of storage at 4°C the amount of TBARS significantly increased only in meat of lambs fed C and L diet. These results encourage the use of olive cake in diet supplemented with linseed, to reduce the lipid meat oxidation phenomena related to the higher level of PUFA.