Abstract
Hepatic lipogenesis in growing chicks given purified diets with various levels of metaboli-zable energy (ME) by the addition of fat or protein was investigated. When dietary ME levels were increased by the addition of fat, total cholesterol content in liver showed the lowest value (P<0.01) in chicks fed diet containing ME 1, 900kcal/kg. NEFA concentration in serum con-tinued to increase in chicks fed diets containing from ME 1, 900 to 3, 100kcal/kg. When dietary ME levels were increased by the addition of protein, triglyceride content in liver showed the highest (P<0.01) and the lowest values (P<0.01) in chicks fed diet containing ME 1, 800 and 3, 200kcal/kg, respectiviely. Total cholesterol content in liver showed the highest value (P<0.01) in chicks fed the diet containing ME 3, 700kcal/kg. Hepatic fatty acid synthesis and activities of NADP-malate dehydrogenase and citrate cleavage enzyme in liver decreased as levels of dietary ME were increased by the addition of fat. Increasing the dietary ME level from 1, 800 to 3, 200 kcal/kg by the addition of protein continued to decrease hepatic fatty acid synthesis and the activity of NADP-malate dehydro genase in liver. However, these were increased in chicks fed diet containing ME 3, 700kcal/kg. Although the activity of citrate cleavage enzyme in liver wasnot affected by dietary ME level from 1, 800 to 3, 200kcal/kg, it increased in chicks fed diet containing ME 3, 700kcal/kg.
