The effect of the increasing the energy content of the diet by supplementation with increasing amounts of carbohydrate on hepatic lipogenesis and the activities of associated enzymes of liver was examined in force-fed growing chicks. Hepatic lipogenesis and the activities of nicotinamide adenine dinucleotide phosphate (NADP-MDH)-malate dehydrogenase (EC 1.1.1.40) and citrate cleavage enzyme (EC 4.1.3.8) in liver were significantly increased as dietary metabolizable energy (ME) increased by supplementation of carbohydrate. Triglyceride content in liver significantly increased as dietary ME increased by supplementation of carbohydrate. The results demonstrated a positive correlation between hepatic fatty acid synthesis and the activities of NADP-malate dehydrogenase and citrate cleavage enzyme in liver.

The effect of increasing the energy content of the diet through supplementation of various levels of fat or protein on hepatic lipogenesis and activities of associated enzymes of liver was examined in force-fed growing chicks. Hepatic lipogenesis was significantly decreased as the dietary metabolizable energy level was increased through supplementation of fat or protein. The activity of nicotinamide adenine dinucleotide phosphate-malate dehydrogenase (NADP-MDH) (EC 1.1.1.40) in liver was higher (P less than .01) in chicks fed diets containing the lowest energy level. The activity of citrate cleavage enzyme (EC 4.1.3.8) in liver was significantly depressed as the dietary metabolizable energy level increased through supplementation of fat, whereas increasing the dietary metabolizable energy level through protein supplementation resulted in a significant increase in citrate cleavage enzyme activity in liver. Nonesterified fatty acid concentration in serum was significantly increased as the dietary metabolizable energy level was increased through supplementation of fat.

Serum lipids of 9 patients with myotonia dystrophica and a myotonia congenita were examined. The contents of serum lipids examined in this study were desmostero~ total cholesterol, triglycerides and free fatty acids (F.F.A.). The fatty acid compositions of cholesterol ester, triglycerides, F.F.A. and phospholipid were also mea-surecL All four lipids were significantly elevated in myotonia dYIr trophicL Desmosterol was abnonnally increased in 8 out of 9 patients. All four lipids were within nonnal range in the myotonia congenita. In myotonia dystrophica, fatty acid compositions were significantly altered in several fractions of F.F.A. and phospholipid; decreases of C14:0 and C16: 1 and an increase of C18: 1 of F.F.A., a decrease of C16: 1 and an increase of C18:0 of phospholipid were all statistically significant. Several significant changes were also observed in myotonia congenita in the fatty acid composition. The changes commonly found in both myotonia dystrophica and myotonia congenita were the increase of C18: 1 of F.F.A. the increase of C 18: 0 and the decrease of C 16: 1 of pholr pholipicL The au thors propose a theory that the degenerative changes of myotonia dystrophica might be attributed to abnormal lipid metabolism, particularlY that of desmosterol-cholesterol conversion and that the abnonnalities of fatty acid metabolism might contribute to the myotonic symptoms in both disease entities.

The effect of increasing dietary fat levels on hepatic lipogenesis in growing chicks was investigated. Increasing the level of dietary fat resulted in a linear depression of both acetate-1-14C and glucose-U-14C incorporation into fatty acids and glyceride-glycerol. Increasing the dietary fat level increased the activity of NADP-isocitrate d ehydrogenase. Chicks fed fat-free diet had lower (P<0.05) activity of NAD-malic dehydrogenase than those fed diets containing 5%, 10% and 15% fat. Activity of glucose-6-phosphate dehydrogenase was higher (P<0.05) in chicks fed fat-free diet. The increase of the level of dietary fat resulted in a linear increase in non-esterified fatty acids in serum. The inverse relationship between the rate of fatty acid synthesis and the level of non-esterified fatty acids in serum suggested a role for non-esterified fatty acids in the control of fatty acid synthesis. Jap. J. Zootech. Sci., 50 (2) : [100][101][102][103][104][105][106][107] 1979 We have previously reported that increases of dietary protein levels resulted in a depression in capacity for hepatic fatty acid synthesis in growing chicks1). On the other hand, the increase of the level of dietary fat has been reported to depress fatty acid synthesis in both liver 2-4) and adipose tissue 5-7) of the laboratory rat. The lipogenic effects could be attributed to dietary component since the increase of dietary fat is generally associated with a decrease in carbohydrate levels. The work of HILL et al.4), however, suggests that dietary fat has a specific inhibitory effect on hepatic lipogenesis unrelated to a reduced carbohydrate intake. Also, the effect of dietary fat on lipogenesis in growing chick liver has been studied but only to a cerain extent .Hence, in the present experiment, we have studied the effects of dietary fat level on in vitro lipogenesis as measured by the incorporation of acetate-1-14C or glucose-U-14C into fatty acid by liver slices of the growing chicks . In addition, the activities of NAD-malic dehydrogenase, NADP-isocitrate dehydrogenase and the pentose pathway dehydrogenases were also studied. Day-old male White Leghoon chicks obtained from a local hatchery were used for the experiment. They were raised on wire floors. Feed and water were made available at all times. Upon reaching the age of 28 days old, all the chicks were weighed individually and divided into 4 groups. Thereafter, they were randomly distributed to the different treatment with 5 birds assigned to each treatment.The birds were housed in portable wire battery from where ad libitum supply of feed and water was freely accessible. Body weight and feed consumption were determined at weekly intervals. The chicks were fed the experimental diets for 21 days. The four groups were fed purified diet containing 0%, 5%, 10% and 15% fat, respectively. The composition of the purified diets is shown in Table 1.At the termination of the 3-week experimental period, all the chicks were weighed for their final body weight and then sacrificed one by one b...

The influence of dietary protein on hepatic lipogenesis in growing chicks was investigated. In vitro study using liver slices demonstrated that the incorporation of acetate-1-14C or glucose-U-14C into fatty acids and glycerids-glycerol was significantly depressed as the protein level increased. Activity of NADP-isocitrate dehydrogenase was lower (P<0.01) in chicks fed 10% protein diet. Activities of the pentose pathway dehydrogenases significantly decreased as the dietary protein level increase from 10% to 40%. Increasing the dietary protein level from 10% to 40% significantly decreased the activity of NAD-malic dehydrogenase. The possible regulatory mechanisms responsible for the depression of hepatic lipogenesis in chicks fed a high protein diet are discussed. It is suggested that a limitation in the availability of cytoplasmic reducing equivalents may initiate the reduction in hepatic fatty acid synthesis of chicks fed a high protein diet. In addition, concentration of various lipids in liver and serum was affected by dietary protein level. Jap.