1. Biological enzyme preparation should be included in formula cost calculation

Microbial Phytase Produced by bioengineering can degrade phytate, release available phosphorus, calcium, energy and protein, and the amount of phosphorus, calcium and other nutrients released increases linearly at the recommended level. When the phytase level was higher than 500ftu / kg, the release of nutrients would continue to increase, but the release of phytate per unit tended to decrease.

Therefore, it is not economical to add phytase beyond the recommended level. β - glucanase and pentosanase can effectively degrade β - glucan and pentosan contained in some feedstuffs. These two water-soluble non starch polysaccharides are antinutritional factors. These antinutritional factors can combine with a large amount of water to increase the viscosity of digestive fluid. Reduce the effect of nutrient substrate and digestive tract endogenous enzymes, resulting in the decrease of the effectiveness of nutrients. When β - glucanase and pentosanase were added to corn soybean meal diet with less antinutritional factors, the improvement of animal production performance was not obvious; when β - glucanase and pentosanase were added to rye, barley and wheat diets and diets with more unconventional feed materials, the improvement of animal production performance was significant.

With the increase of the content of unconventional feed in the same diet, the improvement effect of biological enzyme is more obvious; with the increase of the content of enzyme in the same diet, the improvement effect is more obvious, but the improvement effect of unit enzyme is decreased. No matter what kind of feed material, it is not economical to add β - glucanase and pentosanase in excess. In conclusion, enzyme preparation should be included in formula cost calculation when preparing low cost diets and calculating benefit.