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.

Sixty-seven students suffering from nightblindness in a middle school in Peking were examined with a new apparatus designed by us for the dark adaptation test before and after the treatment of the disease during April, 1955. This apparatus was equipped with a series of holes with different luminosity. The time needed to see all the holes before and after the treatment with vitamin A, was 118 and 62 seconds respectively. In the following spring, a year after diet improvement program was started, there were no complaint of nightblindness among the students. In May, 1956, 49 students who had sufferred from nightblindness in the previous year, were reexamined with the same apparatus, and the time needed was 45 seconds When this result was compared with that of a vitamin A supplemented group (31 seconds), there was no significant difference.From the above findings, it has been shown that nightblindness can be prevented by improvement of the diet alone, and the above apparatus is suitable for the diagnosis of nightblindness for mass nutritional survey. The description of the apparatus is presented in the text.

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.

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

1.The nutrient content of yeast (Condida Y-17) grown on n-alkane studied in this experiment was comparable to that of the same type of yeast produced in other countries. Its content of lead, arsenic, mercury and benzo (a) pyrene were within the limit proposed by the Protein-Calorie Advisory Group of the United Nations System. The Content of its residual n-alkanes and total aromatic hydrocarbons were within or a little over that limit. It is a good supplementary protein feed.2.The corrected PER values were, yeast grown on n-alkane 1.18; deli pid and denucleic acid yeast grown on n-alkane 1.16; brewer's yeast 1.52; full fat soybean meal 1.81. The PER of yeast grown on n-alkane was significantly lower than those of other samples. When 0.3% DL-methionine was added to the diet, the corrected PER values increased: n-alkane grown yeast 2.32; delipid and denucleic acid n-alkane grown yeast 2.49; brewer's yeast 2.35; full fat soybean meal 2.28. The corrected PER value of casein used for correction was 2.43, it was standardized with ANRC reference protein (PER = 2.50).3.Yeast grown on n-alkane with and without removal of lipids and nucleic acid was fed to groups of rats at a dietary level of 25% and 35% respectively for 1 year. A stock diet group and a brewer's yeast diet group were used as control. In the first 3 months the weight gain and feed consumption of the rats fed n-alkanc grown yeast diet were lower than those of the two control groups. The male rats were more sensitive to the change of diet. In the later 9 months the difference of weight gain among different groups were not significant. The concentration of haemoglobin, red cell counts, white cell counts, GPTase activity, serum cholesterol levels and serum urea levels determined at the beginning and the end of the experiment were all in the normal ranges. The concentrations of n-alkanes and odd-chain fatty acids in the adipose tissue of the n-alkane grown yeast group were higher than those of the two control groups, and the difference was highly significant. The concentrations of total aromatic hydrocarbons and benzo(a) pyrene in the muscle of different groups of rats were 0.4-0.6 ppm and 0.4 ppb respectively. No detrimental effect was observed in pathological examination.4.When 5% fish meal or 3.5% casein was added to the 25% n-alkane grown yeast diet, the weight gain and feed consumption of weanling rats were improved significantly, though it was still inferior to those fed with stock diet.5.Strongly growth depressive effect was noted as the level of n-alkane grown yeast was increased to 20% in the diet. This depressive effect was neither due to the toxicity of the residual n-alkanes and aromatic hydrocarbons, nor due to the deficiencies of potassium and selenium in the diet. It might be the result of nutrient or nutrients imbalance of the diet. The appropriate amount of yeast grown on n-alkane used in mixed feed should not be more than 15%.