Exogenous alkaline phosphatases in improving growth, efficiency of nutrient utilization and gut fermentation in pigs

提高饲料转化效率，同时最大限度地减少对环境的不利影响，是提高安大略和加拿大养猪业有限利润率的主要方向，特别是当饲料抗菌剂作为生长促进剂现已被禁止在加拿大的商业断奶猪饲料。已有大量文献证明，碱性磷酸酶（AP）对肠道环境中病原菌的内毒素解毒至关重要，从而维持猪的肠道功能。但断奶仔猪肠道内源AP活性不足以发挥这种生物学作用。因此，需要开发外源性补充AP作为肠道调节剂，以增强肠道消化功能，改善肠道发酵，提高猪的生长性能。此外，外源性饲料AP可以调节肠道微生物平衡，从而潜在地调节和减少挥发性致臭化合物如粪臭素在猪中的生物合成和粪便排泄。在猪营养中使用外源性补充AP的概念已被报道;然而，外源性饲料AP作为新型外源性饲料酶和肠道改良剂的商业应用尚未得到政府的建立和批准。因此，本研究拟开展以下研究：（1）研究在典型的加拿大东部和西部猪日粮中添加外源性饲料AP对提高断奶仔猪的总体生长性能和营养物质消化利用率的影响;和ii）检查饲喂外源饲料AP的最佳水平对总体生长性能的影响，营养物质的消化利用和挥发性气味引起的化合物在生长肥育猪饲养典型的东部和西部加拿大猪饮食，分别粪便排泄。加拿大猪肉行业通过实施该拟议项目的预期效益将通过促进外源饲料AP作为一种新出现的有效肠道调节剂的商业化和应用来实现，以提高整体生长性能，饲料转化率和利润率;并减少来自猪的粪便挥发性气味化合物对环境的负面影响。

Improving feed conversion efficiency while minimizing detrimental impacts on the environment is a major direction to improve limited profit margins in Ontario and the Canadian swine industry particularly when feed antimicrobials as growth promoters have now been banned in commercial weanling swine diets in Canada. It has been well documented that alkaline phosphatases (AP) are essential to detoxify endotoxins from pathogenic bacteria in the gut environment, thus maintaining gut functions in pigs. However, weanling pig gut endogenous AP activities are insufficient in playing such biological roles. Thus, exogenous supplemental AP need to be developed as gut modifiers to enhance gut digestive functions, improve gut fermentation, and increase growth performances in swine feeding. Furthermore, exogenous feed AP can modulate gut microbial balancing, thus potentially modulate and reduce biogenesis and fecal excretion of volatile odor-causing compounds such as skatole in pigs. The concept of using exogenous supplemental AP in swine nutrition has been reported; however, commercial applications of exogenous feed AP as novel exogenous feed enzymes and gut modifiers are yet to be established and approved by the government. Therefore, this proposed research project is: i) to investigate effects of dietary supplementation of optimal levels of exogenous feed AP on improving overall growth performances and digestive utilization of nutrients in weanling pigs fed typical Eastern and Western Canadian swine diets; and ii) to examine effects of feeding optimal levels of exogenous feed AP on overall growth performances, digestive utilization of nutrients and fecal excretion of volatile odor-causing compounds in growing-finishing pigs fed on typical Eastern and Western Canadian swine diets, respectively. Anticipated benefits for Canadian pork industry through conducting this proposed project will be achieved through facilitating the commercialization and applications of exogenous feed AP as a newly emerged effective gut modifier to improve overall growth performances, feed conversion and profit margins; and to reduce the negative environmental impacts of the fecal volatile odor-causing compounds from swine.