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The present experiments were carried out on the relationship between triglyceride synthesis and fatty acid oxidation in liver of chicks treated by estrogen, in order to study on the mechanism underlying estrogen-induced hypertriglyceridemia. Estrogen treatment increased the incorporation of 14C-acetate into fatty acid and of 14C-palmitate into triglyceride in vivo and in vitro. This result suggests that triglyceride synthesis is stimulated by estrogen.The 14C incorporation from [1-14C] palmitate into CO2 in vivo and in vitro was decreased by estrogen treatment, whereas that from [1-14C] acetate into CO2 in vitro was increased.This result suggests that fatty acid oxidation is suppressed by estrogen.The results described above suggest that the combination of increased rate of triglyceride synthesis and decreased rate of fatty acid oxidation in liver may, at least in part, contribute to estrogen-induced hypertriglyceridemia. The specific activities of all the hepatic lipogenic enzymes examined were increased by estrogen treatment.Jpm. J. Zootech. Sci., 53 (10): [699][700][701][702][703][704][705][706] 1982

Triglyceride synthesis and fatty acid oxidation in chick adipose tissue were studied by measuring the incorporation of [1-14C] acetate or [1-14C] palmitate into triglyceride and CO2 in vivo and in vitro in order to investigate the effect of estrogen on adipose tissue accumulation in chicks. Estrogen treatment increased the incorporation of 14C-acetate into total fatty acid and of 14C -palmitate into triglyceride . This result suggests that de novo triglyceride synthesis is stimulated by estrogen. Incorporation of 14C-palmitate into CO2 was increased by estrogen treatment, whereas that of 14C-acetate into CO2 was decreased. This result suggests that fatty acid oxidation is also stimulated by Jpn. J. Zootech. Sci., 51 (9): [673][674][675][676][677][678][679] 1980

Digestion trial was conducted on Japanese deer (Cervus nippon Temminck) to know the carrying capacity of Zoysia-type grassland in Nara Park. Three adult does of good temper were immobilized with succinylcholine chloride, weighed and moved into the feeding stall. These stall allowed quantitative control of feed intake and collection of fecal samples uncontaminated with urine or hair to study digestion coefficients for feed. Deer 1 (6 years old, 49kg of body-weight) and Deer 2 (6 years old, 48kg) were given Zoysia-type grass hay (Zoysia japonica Steudel) and Deer 3 (4 years old, 40 kg) was given alfalfa (2nd cutting) hay as a single component respectively. After the adjustment period of 5 days and the preliminary period of 10 days, total fecal samples were collected for 5 days and feed digestibility was studied. Average daily consumption of Zoysia-type grass was 13.8g per kg bodyweight for Deer 1 and 18.8g for Deer 2. That of alfalfa was 12.9g for Deer 3. Apparent digestibility (%) of the proximate components and detergent fibers are as follows: dry matter in Zoysia-type grass, 65.0 for Deer 1, 62.5

The effects of dietary protein and fat levels on in vivo hepatic lipogenesis and on the hepatic concentration of various metabolites in chicks were investigated. Fatty acid synthesis in liver was depressed by increasing the dietary fat level. Also, the reduction in hepatic lipogenesis was observed when the dietary protein level was increased from 17 to 33%, but no further reduction in lipogenesis occurred in chicks fed the 67% protein diet. The ratio of lactate/pyruvate was calculated in order to estimate the redox state of cell cytoplasm of liver. The ratio was markedly decreased with increasing dietary fat. The ratio was also decreased when the dietary protein level was increased, but no significant difference in the ratio was observed between the chicks fed the 33% protein diet and those fed the 67% protein diet. The hepatic concentration of free CoA in chicks fed the 33% and 67% protein diets and the 11% fat diet was higher than that in chicks fed the 17% protein diet. The concentration of acetyl-CoA was decreased by increasing the dietary protein or fat level, but the reduction was not observed in chicks fed the 67% protein diet. The concentration of long-chain acyl-CoA was increased by feeding the 39% fat diet and the 33% and 67% protein diets to 4.8, 3.3 and 2.3 times the level in chicks fed the 17% protein diet, respectively. The concentration of citrate was markedly decreased by feeding the 67% protein diet, but feeding the 33% protein and the 11% and 39% fat diets had no effect on citrate concentration. Jpn. J. Zootech. Sci., 51 (9): [664][665][666][667][668][669][670][671][672] 1980 Hepatic lipogenesis in chicks is influenced by dietary protein as well as by dietary fat1, 2). An increase in the level of dietary fat or protein depresses fatty acid synthesis in chick liver. LEVEILLE et al.2) reported that the depressing influence of dietary protein on hepatic fatty acid synthesis in chicks was greater than that of dietary fat and suggested that dietary protein and fat depressed fatty acid synthesis through different mechanisms.It was shown in the previous paper3), however, that the hepatic activity of fatty acid synthesis in chicks fed the 67% protein diet for 10 days from hatching time was about 59% of the value observed in chicks fed the 17% protein diet, whereas feeding of 39% fat diet produced only slight lipogenesis. In this experiment, the effects of dietary protein and fat levels on hepatic lipogenesis in chicks were investigated in terms of the redox state in the cytoplasm of liver cell and the concentration of citrate (an activator of lipogenesis), long-chain acyl-CoA (an inhibitor of lipogenesis), and some other metabolites involved in lipogenesis.Jpn. J. Zootech. Sci., 51 (9): 664-672 664 1980

Several workers have indicated that the number of cells increases during embryonic growth, but that the multiplication of skeletal muscle fibers does not take place after birth. Since, however, skeletal muscle fibers are multi-nucleated, this result does not eliminate the possibility that nuclear division takes place in the skeletal muscle of the growing chicks.

The existence of diurnal rhythm in both protein and carbohydrate metabolisms in different tissues of avian species and mammals has been demonstrated by many researchers1). As to a rhythmic change in lipid metabolism, it has been shown that cholesterol synthesis in the liver2) and intestinal mucosa3) of rats possesses a diurnal rhythm and that this rhythmic change is associated with a change in the activity of 3-hydroxy-3-methylglutaryl-CoA reductase [EC 1. 1. 1. 34], the rate-limiting enzyme for cholesterol synthesis4,5). Moreover, PEARCE6) has indicated an apparent diurnal rhythm in fatty acid synthesis in the liver and adipose tissue of laboratory rodents, although the periodic fluctuation in the activity of the rate-limiting enzyme for fatty acid synthesis has not been examined. In avian species, however, the rhythmic change in lipid metabolism has been studied less, with the exception of the changes in the activities of hepatic and intestinal 3-hydroxy-3-methylglutaryl-CoA reductases7).It is well known that fatty acid synthesis plays an important role in lipid metabolism and that the liver is a major site of fatty acid synthesis in chicks6). Therefore, this investigation was carried out to examine the existence of diurnal variation in fatty acid synthesis and lipogenic enzyme activities in the liver of chicks. Materials and Methods AnimalsSingle-Comb White Leghorn male chicks were used and fed a commercial chick starting ration from day-old until they reached a body weight of approximately 340g. The chicks were kept on a 12 hour light-12 hour dark cycle with Feed and water were given ad libitum throughout the test period. Hepatic fatty acid synthesis and lipogenic-enzyme activities were measured at intervals of 4 hours over a 24 hour period.

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