Study On Production Of Phytase And Its Influence To The Utilization Of Ca And P In Pigs

The phytase can be used to degrade the phytate in the feedstuffs and releaseinorganic phosphate.It is important to increase the availability of phosphate in thefeedstuffs,decrease the environmental phosphate pollution from the dejection oflivestock and poultry with high level of phosphate and improve the absorption of themineral nutrition in feedstuffs by monogastric animals.So the study on phytase is ofgreat value in science and application.The strains to produce the high-activity phytase were identified by mutation andselection to aspergillus niger in experiment, and on this basis, through thesingle-factor test, and the solid medium was optimized. Highly active phytase wasproduced by solid fermentation. Finally, phytase to be produced was applied in thepractice of raising pigs in the rural traditional breeding methods to be tested useefficiency of Ca and P.The main conclusions of the study are as follows:1. Through mutation and selection to Aspergillus niger, two strains to producehigh-activity phyase were selected, the two mutant strains through generationsshowed the UV-30 had the stable heredity.2. Through the optimization of the media, the best formula of mediawere:Ratio of nutrient salt and training matrix were 1:1. formula of nutrient salt were:KH₂PO₄17ppm, KCl 0.04%, MgSO₄0.2%, FeSO₄·7H₂O 0.003%, 0.2%Tween-80,(NH₄) ₂SO₄0.94%, pH value 5.0. The matrix is composed by the rice bran and thecorn, the ratio of the two were 3:1. In addition, each adding casein 0.17g in 8g drymedia. Ratio of dry media and water were 2:3, phytase activity produced by themutant strains of Aspergillus niger in optimized media could reached 70U/g drymedia.3. The experiments proved that thermostability of the phytase fluid is good, andit was better that phytase was extracted continuously 10-12h in acetic buffer.4. Adding a certain amount of phytase in sow feedstuffs by the rural traditionalway of feed had apparently effect to reduce fecal phosphorus emission, to promote theavailability of phosphorus in feed, However, it had not significant results to the utilityof calcium.