Transgenic mice expressing bacterial phytase as a model for phosphorus pollution control

Area of Science:

• Animal biotechnology
• Molecular biology
• Agricultural science

Background:

• Phytate is a major source of phosphorus in monogastric diets but is poorly digestible.
• Dietary phosphate supplements are common, contributing to environmental phosphorus pollution.

Purpose of the Study:

• To investigate the efficacy of endogenous phytase transgene expression in the digestive tract.
• To assess the impact of salivary phytase on phosphorus bioavailability and excretion.

Main Methods:

• Development of transgenic mouse models expressing phytase transgenes.
• Utilized rat R15 proline-rich protein promoter and mouse parotid secretory protein promoter for salivary gland expression.
• Quantified fecal phosphorus levels to determine bioavailability.

Main Results:

• Transgenic phytase was highly expressed in parotid salivary glands and secreted as active enzyme in saliva.
• Salivary phytase expression led to an 11% reduction in fecal phosphorus.
• Demonstrated enzymatic activity of the 55 kDa glycosylated phytase protein.

Conclusions:

• Endogenous expression of salivary phytase transgenes is effective in increasing phosphorus bioavailability.
• This biotechnology presents a viable strategy to reduce reliance on dietary phosphate supplements.
• Salivary phytase offers a promising approach to mitigate phosphorus pollution in animal agriculture.