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

断奶后一段时间内消化功能紊乱和生长率下降是保育猪管理的主要问题之一。仔猪在此期间经历应激，主要是由于食物成分的变化，导致黏膜受损，减少营养物质的消化和吸收。因此，更多的底物可用于肠道致病菌，仔猪变得更容易感染和腹泻。开发一种促进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生产性能。已知表皮生长因子（EGF）可刺激肠道发育，在配方奶中添加EGF可促进轮状病毒感染仔猪肠道的恢复。我们假设，使用食品级乳酸乳球菌将EGF局部输送到胃肠道可能有利于改善早期断奶仔猪的生产性能。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，并测试将这些表皮生长因子传递细菌添加到饲料中是否能促进仔猪肠道发育，从而提高早期断奶仔猪的生产性能。这是第一个利用食品级细菌（乳酸乳球菌）作为生物反应器，在体内传递对家畜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.