Effects of grass- and concentrate-based finishing systems on the quality of meat from the M. longissimus thoracis of young Sarda bulls

Context. Recent heightened interest of consumers in the origins of their food, together with broader general awareness of environmental matters, has led to an increase in the demand for meat obtained from grazing systems. The importance of local breeds adapted to medium- and low-input production is fully recognised as a means of guaranteeing the sustainability of these farming methods. A finishing system based on pastures and the use of local breeds could both meet the demands of consumers and increase economic returns for Sardinian farmers. Aims. The work evaluated the effects of different finishing treatments (pasture PAS-0C vs hay-concentrate-based diets HAY-C) on the quality of meat from young Sarda bulls and the usefulness of meat chemicals as markers to discriminate between finishing systems. Methods. Twenty-eight young Sarda bulls were assigned randomly to the following two treatments: finished on natural pasture (PAS-0C group, n = 7), and fed on natural pasture hay ad libitum and concentrate (HAY-C group, n = 21). The latter group comprised three levels characterised by an increasing daily dose of concentrates, as follows: 2.5 kg/animal (HAY-2.5C), 3.3 kg/animal (HAY-3.3C), and ad libitum (HAY-ALC). After slaughter at a fixed age (416 +/- 25 days), carcass yield, pH of the Longissimus thoracis (LT) muscle, colour parameters, cooking loss, proximate analysis, cc-tocopherol and cholesterol concentration, and fatty acid composition of intramuscular fat of LT were all determined. The discriminating power of the meat chemicals between the two main finishing systems (PAS-0C vs HAY-C) and among the three groups receiving concentrates and hay (HAY-2.5C, HAY-3.3C and HAY-ALC) was assessed using linear discriminant analysis. Key results. Pasture-based treatment decreased the intramuscular fat and increased the alpha-tocopherol concentration of meat and the proportion of some desirable fatty acids (alpha-linolenic acid and its derivatives eicosapentaenoic acid, docosapentaenoic acid), and improved the value of the ratio of n-6:n-3, without affecting the ultimate pH, colour parameters, and cooking loss. The discriminant procedure was able to discriminate accurately between the two main finishing systems and among the three groups receiving concentrate and hay (P < 0.0001 and P < 0.005 of the Hotel! ing's T-squared test respectively). The concentration of alpha-tocopherol was key to the discrimination of the two main finishing systems, whereas the content of C17:0 and C 18:0i were particularly effective in discriminating among the three groups fed with hay concentrate. Conclusions. Grazing improves some of the meat traits of young Sarda bulls compared with the effects of a hay-concentrate-based finishing diet. The concentration of alpha-tocopherol in meat is an effective marker for discriminating the effects of pasture from those of a concentrate-based finishing diet