The interrelationship between Phosphorus utilization and  metagenome in two contrasting high-yielding laying hen strains
Phosphorus (P) is an important nutrient in poultry nutrition. Organic P stored as phytates in plants is hard to be utilized by non-ruminant animals because of the lack of endogenous phytase enzymes. Accordingly, mineral phosphate or phytase enzymes are supplemented in poultry feed. However, mineral phosphate will be exhausted in the next 100 years. Thus, it is crucial to identify possibilities for improving the P utilization (PU) by poultry and sustainability in the use of P in the diet. Microorganisms present in the gastrointestinal tract (GIT) of layers are involved in the degradation of phytate and phosphorus utilization and are influenced by the host genetics. Therefore, this study aims to characterize the GIT microbiome of two high-yielding laying hens Lohmann Brown-Classic (LB) and Lohmann LSL-Classic (LSL). In Analysis 1, we identified the strain effect on the composition of gut microbiota in low-P-fed laying hens. The results showed that the structure of ileal microbiota in LB hens was different from that in LSL hens, such as Turicibacter sp. TJ11, Turicibacter bilis, and Turicibacter sp. H121, were significant abundant in LB hens. Those species were positively correlated with BW and had moderately positive correlation with the concentration of plasma P. In Analysis 2, we addressed the strain and P effect on the ileal microbiota of hens. The results revealed that diet (normal-P or low-P supply) affected only qualitative aspect of microbiota of LB and LSL hens and strain affected both qualitative and quantitative aspects of microbiota of LB and LSL hens. The abundance of the species Ligilactobacillus animalis, Lactiplantibacillus plantarum, and Loigolactobacillus backii was relatively higher in LSL groups and the abundance of the species Ligilactobacillus salivarius, Ligilactobacillus agilis, Turicibacter sp. TJ11, and Turicibacter sp. H121 was significantly higher in LB groups. These fours species were positively correlated with BW. In the future, we will describe the functionality of the ileum microbiome and reveal the different functional signals related to PU and other efficiency traits in LB and LSL hens. Further, mixed linear models will be utilized to estimate microbiabilities and to determine if the ileal microbiota drives the variation in PU.