Feeding of phytase over-expressed Lactobacillus decreases fecal phosphate in chicken

Phytic acid is the main phosphate pool in plant seeds which are widely used as chicken feedstuff. However, as monogastric animal, chicken can only utilize phytic acid very inefficiently because of lacking effective phytase. The current situation is mineral phosphate supplemented in feedstuff increasing cost and organic phosphate in phytic acid excreted in feces leading to environmental pollution. Probiotic lactobacilli, especially L. acidophilus were innate isolate of health chicken gut microbiota. Except their health-promoting effect, using them as hosts for delivery and secret the appA gene into chicken digestive tract is attractive. The study validated the applicability of this novel strategy with the recombinant L. acidophilus/pTRKH2P that can secret the Eschericha coli appA encoded phytase under the promoter region and signal peptide sequence of lactococcal usp45 gene. In this study, we report the engineering of the recombinant strain L. acidophilus/pTRKH2P, which secrets active phytase and can degrade phytic acid in maize. Feeding of this construct decreased fecal phosphate in chicks compared to control strain that harboring empty vector. Such a strategy improved the utilization of phosphate in phytic acid and decreased phosphate excretion at the same time.