| 摘要 |
To an animal feed is added the liquor (or the dried solids of the liquor) resulting from the aerobic fermentation with Streptomyces aureofaciens of a nutrient medium, exemplified by a medium containing 1 per cent corn steep liquor, 1 per cent sucrose, 0.2 per cent (NH4)2HPO4, 0.2 per cent K2HPO4, 0.025 per cent MgSO4.7H2O, 0.1 per cent CaCO3. Before incorporation in the feed, aureomycin may be removed from the liquor, e.g. from a liquor which has fermented for 24-72 hours at pH 5-8 at 28 DEG C., the aureomycin is removed by increasing the pH to 8.5 or more and separating the precipitate which forms. S. aureofaciens produces in the liquor aureomycin, vitamin B12, another vitamin designated vitamin B12b, and apparently still another growth-stimulating factor, and there are described experiments involving the feeding of chicks to demonstrate that only part of the growth response on diets including the liquor is due to vitamin B12.ALSO:An animal feed contains the growth-promoting factors produced by aerobic fermentation of a nutrient medium with Streptomyces aureofaciens. The value of vegetable protein in particular, in feeds containing such protein, is enhanced by supplementing the feeds with liquor resulting from the fermentation, or the dried residue of this liquor; aureomycin may previously have been extracted from the liquor. Experiments involving the feeding of chicks and of pigs on basal diets supplemented by the liquor are described.ALSO:To an animal feed is added the liquor (or the dried solids of the liquor) resulting from the aerobic fermentation with Streptomyces aureofaciens of a nutrient medium comprising a source of assimilable carbon, a source of nitrogen, e.g. amino acids, casein, meat extract, soybean meal, corn steep liquor, urea, nitrates, and inorganic salts including phosphates, calcium, magnesium, potassium and iron, a typical medium containing 1 per cent corn steep liquor, 1 per cent sucrose, 0.2 per cent (NH4)2HPO4, 0.2 per cent K2HPO4, 0.025 per cent MgSO47H2O, 0.1 per cent CaCO3. |
