A new study has demonstrated that mannanase, an enzyme designed to break down complex carbohydrates in soybean meal (SBM), can significantly enhance broiler performance—particularly in diets with moderate to high levels of SBM under energy-restricted conditions.
Soybean meal is widely used as a protein source in poultry feed, but it contains indigestible compounds such as mannans that can interfere with nutrient absorption and increase energy loss due to immune stimulation. Mannanase helps counteract these effects by breaking down the mannans, thus reducing gut viscosity and improving nutrient uptake.
Researchers from China Agricultural University and partner institutions explored how varying levels of SBM interact with mannanase in low-energy broiler diets. Using Arbor Acres broilers, they designed a controlled 3×2 factorial experiment. Broilers were fed diets containing different SBM concentrations (35.66%, 17.83%, and 8.92%) either with or without 100 mg/kg of mannanase. All diets were formulated with a 50 kcal/kg deficit in metabolizable energy.
The study revealed that mannanase supplementation improved growth performance, especially at SBM levels of 17.83% and 35.66%. Key metrics such as body weight and feed conversion ratio improved, while respiratory metabolism assessments showed more efficient energy use and better nitrogen retention.
At the gut level, mannanase enhanced protein and amino acid digestibility, reduced gut viscosity, improved villus development, and strengthened intestinal barrier function. Inflammatory markers were also reduced, suggesting a more stable immune environment in the gut. Microbial analysis showed reduced levels of harmful bacteria like E. coli and a shift toward beneficial microbial metabolic pathways.
However, these benefits were not observed when SBM content dropped to 8.92%, suggesting the enzyme’s effectiveness depends on having enough substrate (mannans) to act upon.
Overall, the findings offer a practical solution for feed producers and poultry integrators aiming to reduce costs or energy inputs without compromising growth performance. By strategically including mannanase in diets containing moderate levels of SBM, producers can enhance feed efficiency, support bird health, and lessen the environmental footprint of poultry production.
