Objective: To assess the mRNA level of acetyl CoA carboxylase alpha (ACACA), fatty acid synthase (FASN), and stearoyl-CoA desaturase (SCD) by means of real-time PCR in Barki sheep subjected to complete feed deprivation.
Design: Controlled study.
Animals: Seven healthy pregnant ewes.
Procedures: Ewes were subjected to complete feed deprivation with ad libitum water for five consecutive days. Venous blood samples were collected from each ewe before (zero time) and on the fifth day post-deprivation of feed for measurement of the mRNA level of ACACA, FASN, and SCD and assessment of serum metabolic profile parameters.
Results: On the fifth day post-fasting, the gene expression pattern of ACACA, FASN, SCD genes showed a significant (p < 0.05) down regulation in comparison with pre-deprivation of feed. There was a significant (p < 0.05) increase in the serum level of non-esterified fatty acids (NEFA), beta-hydroxyl buteric acid (BHBA), and triglycerides in pregnant ewes in the fifth day post-fasting in comparison with pre-deprivation of feed. On the other hand, there was a significant (p < /em> < 0.05) decrease in the level of glucose, cholesterol, and insulin in pregnant ewes in the fifth day post-fasting compared with pre-deprivation of feed. On histopathology, liver showed marked heptic steatosis in midzonal and periportal area, with formation of small fatty cysts in liver lobule. There was a positive correlation between leptin and insulin (r = 0.996; p < /em> < 0.01), BHB and leptin (r = 0.951; p < /em> < 0.05) and glucose and SCD (r = 1.0, p < /em> < 0.01).  However, there was a negative correlation between FASN and NEFA (r = - 0.991; p < /em> < 0.05), FASN and leptin (r = -0.683; p < /em> < 0.05) and FASN and cholesterol (r = - 0.82; p < 0.05).
Conclusion and clinical relevance: Pregnant Barki ewes can clinically tolerate complete feed deprivation for five days, with down regulation of ACACA, FASN, SCD genes and presence of marked metabolic changes. Therefore, metabolic monitoring is warranted to predict the early changes associated with feed deprivation under different stressful conditions.