Comparison of two phytase products assessed by different regression approaches and the ileal microbiota

The principal reserve of phosphorous in plants, the phytate is a complex substrate which cannot be easily assimilated by broiler chickens, diminishing the availability of nutrients in the gastrointestinal tract (GIT). Thus, it is common to supply alternative sources like mineral feed phosphates and phytase enzymes to meet requirements for phosphorus (P). We aim to study the efficacy of two phytase products, supplemented with different concentrations, on different traits of P determination and their effect in the microbial composition of the GIT. Experimental diets were provided to a total of 864 birds (unsexed broiler strain Ross 308) distributed in 72 pens with 12 birds each. Diets were corn-soybean based, and the treatments consisted in one control and supplementation based on four concentrations of dicalcium phosphate (DCP) (0.7, 1.4, 2.1 and 2.9 g/kg), three concentrations of Natuphos E (250, 500 and 750 FTU/kg) and three concentrations of Natuphos (250, 500 and 1000 FTU/kg). On day 21, birds were euthanized by carbon dioxide followed by anesthesia in a gas mixture. Ileum samples were collected, pooled on a pen basis, and stored at -80°C. Performance data was determined based on feed consumption and weight gain. For microbiota analysis, total nucleic acids were extracted, and 16S rRNA gene was targeted to proceed with amplicon sequencing. Phylogenetic analysis was assessed using Mothur, followed by multivariate statistical analysis.Results: The supplementation of Natuphos E and Natuphos improved bird performance in comparison to the basal diet (control); however, the highest dose for DCP resulted in the higher values. The microbial community showed statistical differences, where the higher levels of supplementation impact in a similar microbial distribution. The OTUs responsible for the changes corresponded to the genus Lactobacillus. The highest abundance across all treatments was registered for Lactobacillus crispatus with 42% for the phytase Natuphos 250 and L. gallinarum with 45% for Natuphos 1000. Conclusions: The presence of phytase in different doses improves bird performance, where high dominance of Lactobacillus was found in the ileum samples. A strong effect is observed with high levels of supplementation in the microbial ecology distribution. Differences are found based on the greater abundance of OTUs, explicitly L. crispatus and L. salivarius, which would have a direct impact on biological functions.