Abstract: The slaughter performance of Sunit sheep and Small-Tailed Han sheep (5-month-old, 10 animals for each breed) was investigated. The quality, fatty acid composition and volatile compounds of Longissimus dorsi muscles from these lambs were comparatively evaluated. The results showed that the meat percentage and bone to meat ratio of Sunit lambs were significantly greater than those of Small-Tailed Han lambs (P < 0.05). In addition, in terms of meat color parameters (a* and b*) and tenderness Sunit lambs were better than Small-Tailed Han lambs (P < 0.05). There was, however, no significant difference in cooked meat percentage or pH between the two breeds. Fatty acid analysis showed that the contents of saturated?fatty?acids (SFA) and polyunsaturated fatty acids (PUFA) in Sunit lambs were higher than in Small-Tailed Han lamb. The contents of palmitic?acid (C16:0) and stearic?acid (C18:0) in Sunit lambs were significantly higher than in Small-Tailed Han lambs (P < 0.05), but no significant differences in the dominant unsaturated fatty acids (C18:1, C18:2n6c and C20:4n6) were present between both breeds. The main volatile compounds identified in lamb meat were carbonyl and alcohol compounds and the contents and composition of these compounds were largely affected by breeds with aldehydes and acetones being more abundant and alcohols being less abundant in Sunit lambs than in Small-Tailed Han lambs. Hexanal, octanal nonanal, 1-octen-3-ol and 2, 3-octanedione may be mainly responsible for the formation of meat flavor.

Key words: Sunit lamb, Small-Tailed Han lamb, slaughter performance, meat quality, fatty acids, volatile components