Low zinc (1.4-1.5 ppm) ration containing saturated fat (coconut oil) was fed to weanling rats, death occurred since second week. In third week, total death was 55%. The survivors manifested severe Zn-deficiency symptoms. When they were given Zn supplement in drinking water (100 ppm Zn), the deficient symptoms disappeared quickly and body weights increased rapidly. When coconut oil was replaced by safflower oil, the rats didn't show any Zn-deficiency symptom in 4 weeks. There was no difference in Zn contents of plasma and hair between Zn-deficient rats and the normals. Adjusting fatty acids composition of dietary fat to contain linoleic acid at 20% of total fatty acids, the rats manifested Zn-deficient symptoms after 2 weeks, and Zn contents of plasma and hair were significantly lower than that of normal rats(P

Zinc deficient rats were injected subcutaneously each day for 3 weeks with 250 ?l evening primrose oil (EPO, containing 10% Y-linolenic acid and 73% linoleic acid) or safflower oil (SFO, containing 77% linoleic acid only) and compared with zinc supplemented group (ZnS) and zinc deficient group (ZnD) without injections. At the end of the experiment, rats were killed under anaesthesia, organ weights, zinc content of kidneys, blood cholesterol and fatty acid compositions were determined. The results showed animals in EPO group had the best recoveries both in deficient symptoms and in body weights,the zinc content of kidneys was the highest, the serum cholesterol level was significantly lower than those of SFO and ZnD groups, but no difference from ZnS group. The total percentage of 22-C and above(?-6)polyunsatured fatty acids was the highest among those four groups. These results indicated that?-linolenic acid was beneficial to zinc deficient rats in growth, zinc utilization and the metabolism of essential fatty acids.

Weanling female rats were fed 12% lard diet supplemented with 2 g cholesterol and 60 mg cholic acid per 100 g diet for 52 days. Blood cholesterol levels were then analyzed for individual rat. Animals were divided into 4 groups according to their blood cholesterol levels and body weights. One group of animals, regarded as negative control, was killed immediately. The other 3 groups were fed 12% level of synthetic oil, lard or soybean oil diet respectively without cholesterol and cholic acid supplementation for 3 weeks. During the 3 weeks of rehabilitation, the following parameters were measured: body weight and serum cholesterol levels, every week; food intakes, every other day; high density lipoprotein cholesterol (HDL-C) levels at the beginning and the end of the rehabilitation period; fecal steroids excretion, including neutral and acid steroids from the 2nd to the 4th day of rehabilitation; liver weights, liver fat contents and liver cholesterol levels after animals were killed.The results showed that no significant effects on body weights, serum cholesterol levels, liver weights and liver fat contents of different kinds of dietary fat were observed during the rehabilitation period of hyperch-olesterolemia. But synthetic oil, as well as soybean oil diet caused a lower liver cholesterol levels, and higher levels of both serum HDL-C and fecal neutral steroids.

Wistar rats, fed laborotory stock diets, were randomly divided into three groups, given cholesterol oxides (Och) and purified cholesterol (Pch) (at a dosage of 250mg/kg/day), and gelatin (control group) through stomach tube for 2 successive days. In the first part of the experiment, Evans blue, dissolved in normal saline, was injected into the tail veins 18 hrs after last tube feeding and the rats were killed 2 hrs following the injection, The aorta were excised for determination of the endothelial permeability by fluorophotometry. In the second part of the experiment, the rats were sacrificed 24 hrs after last tube feeding. The aorta were prepared for the observation of the aortic endothelium under scanning electronic microscope. The results showed that the endothelial permeability of rats fed Och was much higher than those fed Pch and gelatin (P0.05). Scanning electron microscopic observation showed that severe endothelial damage occ-ured in the Och rats, while the aortic endothelium from the rats fed Pch revealed relatively mild degeneration. Results were briefly disscussed.

The aim of this experiment is to investigate the effect of teaseed oil which contains about 76% oleic acid on blood lipids and platelet function. Adult Newzealand female rabbits of 2-3 kg body weight were divided into 3 groups of 6-8 animals each. Stock diet was given with 5 ml of coconut, teaseed or safflower oil to each group plus 0.5g of cholesterol by using stomach tube every day for 8 weeks. The results showed serum total cholesterol (TC), LDL-C, platelet aggregation and plasma TXB2 level were significantly reduced in teaseed oil group as compared with that of coconut oil group. Serum TC, LDL-C were lowered too in safflower group, but it was not significantly different from that of coconut oil group. Ratio of serum HDL-C/TC in teaseed oil group was significantly higher than other two groups, and TXB2/6-keto-PGF1a ratio was decreased about 30% when compared with the two other groups, but with no statistical significance.Male Wistar rats were divided into 4 groups of 30 animals each and were fed for 9 weeks with semisynthetic diets containing 15% coconut, teaseed or safflower oil and 1% cholesterol respectively. Teaseed oil was found to cause a lower level in platelet aggregation and a significant reduction in plasma TXB2/PGF1a ratio. Analyses of fatty acid composition of platelet membrane showed the MUFA content was much higher and that of the ?-6 PUFA was obviously less in teaseed oil group. The results together with that obtained in rabbit experiment clearly indicated MUFA (mainly oleic acid) exerting beneficial effect on the prevention of cardiovascular diseases. Its possible pathway was discussed in the text.

The effects of synthetic oil used as dietary fat source on the body weight, organ weight, liver and serum lipids of rats during the hypercho-lesterolemic inducing period were investigated, and comparison was made with lard and soybean oil diets.Weanling albino rats were fed first with stock diet for 3 weeks. Bloods were collected from tails, and serum cholesterol contents were determined. Based upon the body weight and serum cholesterol level, animals were then divided into 5 groups. Four groups were fed respectively with synthetic oil, synthetic oil plus linoleic acid, lard and soybean oil diets, all were supplemented with 1% cholesterol. The, fifth group served as control, was fed with soybean oil diet without cholesterol. Body weights and serum lipids (cholesterol and triglyceride) were measured at intervals during the experiment. Organ weights and liver lipids (total fat, cholesterol and triglyceride) were determined at the end of the experiment.The results showed that there was marked sex difference between male and female rats, that is, synthetic oil diet caused significant lower body weights and lower serum cholesterol levels to female but not to male rats.Cholesterol inducing diets apparently increased the liver weights of all animals, yet fat accumulation only occured in those livers of rats fed with lard and soybean oil diets. The liver fat contents of animals of both synthetic oil and synthetic oil plus linoleic acid groups were at normal level.This experiment reveals that when dietary cholesterol intake is high, the use of synthetic oil as a dietary fat source for maintaining a normal lipid metabolic condition in the body seems beneficial.

A nutritional survey of lactating mothers in different lactating periods was carried out in urban, suburban and rural districts of beijing in 1983-1984. Milk were collected, and its lipid compositions, including specific gravity, fat, cholesterol and fatty acids were analyzed. The results were as follows:1.The average of specific gravity of 207 milk samples were from 1.018 to 1.022. Though the value of the rural district was higher (1.022). The difference was rather small.2.216 milk samples were determined for the fat content (g%). The average of urban district was 3.78, of suburban 3.31 and of rural 3.08. Differ-eces between urban and other two districts were significant.3 .Milk cholesterol content was determined in 194 samples. The content in colostrum was the highest, 23.4mg/100g, but decreased gradually and steadied at about 10mg/100g in three months. No differece was observed among three districts.4.221 milk samples were analyzed for its fatty acid composition. The main components were oleic acid (29-37%), palmitic acid (17-25%) and lino-leic acid (12-25%), with 1-2% of erucic acid. The linoleic acid content was the highest in rural district.5.Statistical analysis showed that the correlations between milk fat and cholesterol content were significant in all the three districts, but the regression coefficient of urban district was significantly lower than that of rural district.6.There was significant correlation between fat intake of mothers and their milk fat content in total 188 samples, but no correlation was found when three districts were examined separately. All the results showed that the dietary fat intake of mothers might influence their milk fat content. The characteristics of fatty acids pattern of Chinese breast milk was the higher linoleic acid content as compared with other countries. The essential fatty acids in breast milk could meet the infant's need. The cholesterol allowance from breast milk was about 70-85mg per day.