Biotin effects on fatty acid synthesis in chicks.

Data are summarized from several papers on the effects of biotin deficiency on lipid metabolism, especially fatty acid synthesis, in chicks. Biotin deficiency inhibits in vivo lipogenesis and hepatic acetyl-CoA carboxylase (ACC) activity. Although acetate incorporation into fatty acids is inhibited in biotin-deficient chicks, malonate incorporation is not inhibited. In fact, dietary malonic acid stimulates lipogenesis during biotin deficiency as measured by total carcass fatty acid content. Biotin-deficient chicks exhibit altered hepatic and whole body fatty acid composition in comparison with control chicks. The deficiency results in an increased proportion of the 16-carbon to 18-carbon fatty acids, and the most striking increase is for palmitoleic (16:1) acid. Biotin deficiency increases the relative incorporation of palmitate and stearate into phospholipids and decreases the relative incorporation of these fatty acids into triglycerides. Finally, mercury stimulates lipogenesis in biotin-deficient, but not in control, chicks by an unknown mechanism.