EVALUATION OF NUTRITIVE VALUE OF N-ALKANE GROWN YEAST
- VernacularTitle:正烷酵母的营养评价
- Author:
Zeying LI
;
Xihe ZHAO
;
Aizhong FU
;
Yuhai LIU
;
Yanjie SUN
;
Daxun JIN
- Publication Type:Journal Article
- From:
Acta Nutrimenta Sinica
1956;0(02):-
- CountryChina
- Language:Chinese
-
Abstract:
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%.
