Abstract: The study was undertaken to investigate the effect of different feeding conditions on MyomiRs expression in longissimus dorsi and slaughter performance of 12-month-old Sunit sheep. The results showed that growth traits (length, height and chest girth), live weight and carcass weight of sheep in the grazing group were significantly higher than those of sheep in the stall-fed group (P < 0.05), and dressing percentage and lean meat yield of pen-fed sheep were higher than those of grazing sheep. The level of miRNA expression in longissimus dorsi of grazing sheep was higher than in stall-fed sheep. The miR-1 expression in grazing sheep had a significant positive correlation with height, carcass weight and lean meat yield (P < 0.05), and miR-133 expression was also significantly positively correlated with lean meat yield (P < 0.05). But a significant negative correlation between miR-128 expression and lean meat yield was noted for the stall-fed group (P < 0.05). Accordingly, different feeding conditions have an impact on miRNAs expression, thereby further affecting slaughter performance.

Key words: feeding conditions, Sunit sheep, MyomiRs, expression, slaughter performance