Protein Oxidation in M. longissimus dorsi and M. semimembranosus Lambs Reared Indoors and on Pasture

Protein oxidation M. longissimus dorsi and M. semimembranosus was studied in ram lambs of Northeastern Bulgarian Fine Wool Breed and cross of this breed with Ile de France, reared and in doors and on pasture. The degree of protein oxidation is determined by measuring the content of carbonyls, formed during the storage of the investigated muscles at low temperatures (4 ?? till 6th day and -20 ?? till 90th day). Protein oxidation was lower in pastured animals. Differences between the groups were significant at 4th (P < 0.05) and 90th day (P < 0.001) for the animals of Northeastern Bulgarian Fine Wool Breed and at 24 h (P < 0.05), 6th and 90th day (? < 0.01) in crossbred lambs. Differences were reported in protein oxidation in the muscles at 48 h (P < 0.01) and the 4th day (P < 0.05) as well as at 48 h (P < 0.05) and the 90th day (? < 0.001), for the lambs of Northeastern Bulgarian Fine Wool Breed and the cross, respectively. The dynamic of changes of the carbonyls in the muscles shows that storage duration influences protein oxidation. The carbonyl contents in M. longissimus dorsi were significantly higher the 90th day of the storage, compared to the other intervals in both indoor reared lambs of Northeastern Bulgarian Fine Wool Breed and the crossbred animals, as well as in pastured crossbred lambs. In M. semimembranosus differences between the contents of the carbonyls in the intervals of measurement and the 90th day of the storage were significant in both animals of Northeast-ern Bulgarian Fine Wool Breed and the cross, reared indoors.