Lei Wang, Yuxin Yang, Bei Cai, Pinghua Cao, Mingming Yang,Yulin Chen
International Journal of Molecular Sciences2014,15(7):12842–12860.
Abstract:A multifunctional transgenic Lactobacillus with probiotic characteristics and an ability to degradeÎ²-glucan and phytic acid (phytate) was engineered to improve nutrient utilization, increase production performance and decrease digestive diseases inbroiler chickens. The Bacillus subtilis WL001 endoglucanase gene (celW) and Aspergillus fumigatus WL002 phytase gene (phyW) mature peptide (phyWM) were cloned into an expression vector with the lactate dehydrogenase promoter of Lactobacillus casei and the secretion signal peptide of the Lactococcus lactisusp45 gene. This construct was then transformed into Lactobacillus reuteri XC1 that had been isolated from the gastrointestinal tract of broilers.Heterologous enzyme production and feed effectiveness of this genetically modified L. reuteri strain were investigated and evaluated. Sodium dodecylsulfate polyacrylamide gel electrophoresis analysis showed that the molecularmass of phyWM and celW was approximately 48.2 and 55 kDa, respectively,consistent with their predicted molecular weights. Endoglucanase and phytase activities in the extracellular fraction of the transformed L. reuteri culturewere 0.68 and 0.42 U/mL, respectively. Transformed L. reuteri improved the feedconversion ratio of broilers from 21 to 42 days of age and over the whole feeding period. However, there was no effect on body weight gain and feed in take of chicks. Transformed L. reuteri supplementation improved levels of ash, calcium and phosphorus in tibiae at day 21 and of phosphorus at day 42. In addition, populations of Escherichia coli, Veillonella spp. and Bacteroidesvulgatus were decreased, while populations of Bifidobacterium genus and Lactobacillus spp. were increased in the cecum at day 21.