Relative phytase efficacy values as affected by response traits, including ileal microbiota composition

Area of Science:

• Animal Nutrition
• Microbiology
• Biochemistry

Background:

• Phytase supplementation is crucial for improving phosphorus utilization in broiler diets.
• Evaluating phytase efficacy requires considering diverse response traits.
• Understanding the impact on gut microbiota is essential for holistic assessment.

Purpose of the Study:

• To compare the relative efficacy of two phytase products (Natuphos E 5000 G and Natuphos 5000 G) against a mineral phosphorus source (dicalcium phosphate) in broiler chickens.
• To investigate the influence of different response traits on phytase efficacy estimation.
• To analyze the effect of these supplements on ileum microbiota composition.

Main Methods:

• Eleven experimental diets were formulated with varying levels of dicalcium phosphate, Natuphos E 5000 G, and Natuphos 5000 G.
• Performance traits, prececal phosphorus digestibility, and tibia/foot ash were assessed.
• Regression analysis and slope ratios were employed for efficacy comparison.
• 16S rRNA gene amplicon sequencing was used to analyze ileum microbiota composition.

Main Results:

• Different response traits resulted in significantly different estimates of relative phytase efficacy.
• Natuphos 5000 G required a 1.75-fold higher activity to match Natuphos E 5000 G's response, with variability from 1.59 to 1.91 across traits.
• Ileum microbiota composition, including specific Lactobacillus species, showed no significant differences among dietary groups.

Conclusions:

• The choice of response trait critically influences the estimated relative efficacy of phytase products.
• Phytase supplementation, at the tested levels, did not alter the overall ileum microbiota composition in broiler chickens.
• Further research is needed to harmonize methods for accurate phytase efficacy evaluation.