[Absorption and use of differently structured protein isolates by rats]

Area of Science:

• Nutritional biochemistry
• Animal nutrition
• Protein metabolism

Background:

• Dietary protein structure influences nutrient bioavailability.
• Understanding protein digestion and absorption is crucial for animal health and feed formulation.
• Horse bean protein is a potential plant-based protein source.

Purpose of the Study:

• To investigate the impact of different protein structures on nitrogen balance and absorption in growing rats.
• To compare the nutritional value of isolated, hydrolyzed, and fiber-bound horse bean proteins.
• To assess the influence of protein processing on endogenous nitrogen excretion and true nitrogen absorption.

Main Methods:

• Nitrogen balance and absorption experiments were conducted using growing albino rats.
• Four different protein preparations were tested: isolated horse bean protein, hydrolyzed horse bean protein with supplements, horse bean-casein fibers, and supplemented isolated horse bean protein.
• Endogenous nitrogen excretion was quantified using the isotope dilution method.

Main Results:

• Hydrolyzed horse bean protein exhibited the lowest digestibility and utilization values.
• Endogenous nitrogen excretion was significantly higher for hydrolyzed protein compared to intact proteins.
• True nitrogen absorption in the small intestine was diminished with hydrolyzed protein, impacting chyme transit.
• Horse bean protein-casein fibers showed reduced protein utilization and increased endogenous nitrogen excretion compared to supplemented isolated protein.

Conclusions:

• Protein hydrolysis and fiber incorporation alter protein digestibility and utilization negatively.
• Processing methods significantly affect nitrogen absorption and endogenous nitrogen excretion.
• The endogenous nitrogen contribution is relatively constant in the small intestine but varies in the large intestine based on protein utilization.