THE SEASONAL EFFECTS ON IMF CONTENT OF FAS mRNA EXPRESION IN MUSCLES OF MONGOLIAN SHEEP

Abstract

This survey’s aim was to investigate the seasonal effect of Fatty acid synthesis (FAS) expression on intramuscular fat (IMF) content in grazing Mongolian, Ujumqin and grain-fed Ujumqin sheep. Different skeletal muscles of sheep (biceps femoris, longissimus dorsi and triceps brachii) were sampled to measure IMF content and total RNA was extracted to determine FAS mRNA expression levels by real-time PCR. The result revealed that: (1) The difference in IMF content in the muscles of Mongolian sheep grazed in summer was observed to be much higher than sheep grazed in winter (p<0.01). Also there was significant difference in IMF content in the muscles of Ujumqin sheep grazed in summer than winter (p<0.05). The mRNA expression level of FAS in muscles of winter grazing Mongolian sheep was significantly higher than summer (p<0.05). The seasonal effects on IMF content in the muscles and it’s FAS mRNA gene expression was all negative correlated between the sheep breeds. Accordingly, grazing Mongolian sheep’s FAS gene expression level was very high negatively correlated (r=-0.964). This study suggested that grazing Mongolian and Ujumqin sheep able to store large amount of IMF under depends on seasonal effects.