| 摘要 |
An additive for an animal feedstuff comprises dried invertase-containing micro-organisms, particularly yeast, having an invertase activity of at least 10. (The invertase activity is the number of grams of sucrose which would be hydrolysed by 1 gram of the dry yeast when incubated with sucrose in acetic acid buffer of pH 4.5 at 37 DEG C. for 2 hours). Other invertase-containing micro-organisms such as Aspergillus and Penicillium spp. may be employed. The dried additive may form from 0.05-5% by weight of the dry feedstuff. When included with sucrose, the dried additive and the sucrose may form from 0.01-3% and from 10-30%, respectively, by weight of the dry feedstuff, the dried additive being present in an amount sufficient to hydrolyse all but a small amount (say 5%) of the sucrose. According to an example, a yeast slurry of 15% solids content was spray-dried to a moisture content of 5.6% in an apparatus providing an inlet temperature of 170 DEG C., an outlet temperature of 85 DEG C. and an average residence time at 85-90 DEG C. of 1 1/2 minutes. The invertase activity of the spray-dried yeast was 500, as compared with 650 for the fresh yeast. |
