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Effect of linseed diet on intramuscular fatty acid profile of bulls slaughtered at different

The study examined the effect of linseed diet and slaughter age on beef carcass and meat quality, and intramuscular fatty acid (FA) profile and oxidative stability. The sample included 80 Simmental bulls reared under intensive production system. The animals (initial age=221±9d) were equally assigned to 4 groups and fed with linseed (L) or control diet until slaughter at 13 or 17 months. Diets were fed ad libitum as total mixture ration (high moisture corn, corn silage, protein supplement and hay), with the addition of whole linseed grain in L diet groups (130 and 160 g per head daily until and after the age of 13 months, respectively). After slaughter, carcass traits (weight, dressing-out %, trimmed fat) were measured and M. longissimus thoracis colour (CIE Lab) and pH, and FA composition (of total lipids) and oxidative stability were determined. Data were analysed by GLM procedure, with the model including slaughter age, diet, and their interaction as fixed effects. As regards to slaughter age, all carcass traits were typically higher (P<0.001) in older animals, which also had a darker (P<0.001) and fatter (P<0.01) meat, but with only few differences in FA composition (e.g. more CLA, P<0.001) compared to younger animals. Diet had no influence on carcass and meat quality, except for a higher dressing-out % (P<0.01) in L diets. Intramuscular fat of linseed fed bulls was less saturated (P<0.01), while for several FA a significant (P<0.05) slaughter age x diet interaction existed. In particular, L diet increased (P<0.05) the proportion of most individual as well as total n-3 FA in yearling bulls but without such response in more grown-up animals. Lipid oxidation, measured during the six-day cold storage was generally more developed in younger and linseed-fed animals.

cattle; beef; slaughter age; fatty acids; linseed

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