Hepatic lipid metabolism in domestic fowl as influenced by dietary cereal.

The influence of dietary cereal on hepatic lipid metabolism was studied in adult Japanese quail and mature female chickens fed isoenergetic and isonitrogenous corn-soy and wheat-soy diets ad libitum. Hepatic lipid accumulation and rate of biosynthesis were significantly higher in birds fed the corn-soy diet. The differential response to the cereals was seen in ovipositing females but not in mature male quail. There were no significant concomitant changes in body composition, egg production, egg weight, body weight, feed, and energy intake. Results of sequential changes in hepatic lipid metabolism showed that reduction in liver fat was significant 2 to 3 weeks after feeding the wheat diet and was due to a significant reduction in rate of lipogenesis and the amount of triacylglycerols deposited. Plasma levels of free fatty acids and glucose were not significantly altered by the dietary regimes in laying hens. In Japanese quail fed the corn-soy diet, plasma glucose was elevated and there was evidence of impaired glucose tolerance. In vitro rate of oxidation of labeled palmitate was significantly higher in liver homogenates from birds fed the corn-soy diet. Addition of carnitine to the incubation mixtures resulted in an increase of equivalent magnitude for both treatments. Liver hemorrhages were observed in laying hens but not in Japanese quail. Addition of myo-inositol to the corn diet for Japanese quail failed to significantly alter hepatic lipid accumulation. These studies show that differences in liver lipid accumulation due to corn and wheat diets are related to changes in rate of lipogenesis.