Production of epidermal growth factor expressing Lactococcus Lactis and its potential for enhancing early-weaned piglet growth

仔猪断奶后消化功能紊乱和生长速度下降是保育猪管理中的主要问题之一。仔猪在此期间经历应激，主要是由于食物成分的变化，导致粘膜受损，减少营养消化和吸收。 因此，更多的基质可用于肠道致病菌和仔猪变得更容易感染和腹泻。开发刺激早期断奶仔猪肠道发育的日粮可能有助于优化其在这一关键阶段的性能。已知表皮生长因子（EGF）刺激肠道发育，并且其补充到配方中显示出促进仔猪肠道从轮状病毒感染中恢复。我们假设使用食品级乳酸乳球菌将EGF局部递送到胃肠道可能有利于改善早期断奶仔猪的性能。我们将使用基因工程的方法来产生分泌表皮生长因子的乳酸乳球菌，并测试是否将这些EGF传递细菌纳入饲料中可以增强仔猪肠道发育，从而提高早期断奶仔猪的性能。这是第一次使用食品级细菌（乳酸乳球菌）作为生物反应器，使用体内方法来递送对家畜动物有益的重组因子的研究。因此，该项目的成功完成将产生高质量的出版物，并为改善动物生产提供新的机会。

Disturbed digestive function and the associated reductions in growth rates during the period immediately after weaning is one of the major problems in nursery pig management. Piglets experience stress during this period, largely due to changes in food composition, leading to a damaged mucosa and to reduce nutrient digestion and absorption.  As a result, more substrate it available for enteric pathogenic bacteria and piglets become more susceptible to infection and diarrhea. Developing a diet to stimulate intestinal development of early weaned pigs may help to optimize their performance in this critical stage. Epidermal growth factor (EGF) is known to stimulate the development of intestine and its supplementation into formulas was shown to facilitate the recovery of intestines in piglets from rotavirus infection. We hypothesized that locally deliver EGF to the GI tract using food-grade Lactococcus Lactis may be beneficial for improving early-weaned piglet performance. We will use a genetic engineering approach to generate Lactococcus Lactis that secrets epidermal growth factor and test if including these EGF delivering bacteria into feed enhances piglet intestinal development, and thus, early-weaned piglet performance. This is the first study using the in vivo approach to deliver recombinant factors that are beneficial to the livestock animals using food grade bacteria (Lactococcus Lactis) as bioreactor. Successful completion of the project should therefore generate  high quality publications and provide novel opportunities for improving animal production.