Allium-Based Phytobiotic Enhances Egg Production in Laying Hens through Microbial Composition Changes in Ileum and Cecum

Simple Summary: The misuse of antibiotics has led several countries to ban their use as prophylactics against bacterial diseases or as growth promoters in livestock and poultry. Phytobiotics (bioactivecompounds extracted from plants) are one of the alternatives, due to their antimicrobial activity andits modulation of the gut microbiota and the improvement of productive properties. Garlic and onionextracts, rich in antimicrobial compounds, are of the most promising alternative to antibiotics. We supplemented a garlic- and onion-based product in the diet to laying hens at the beginning of their productivelife. The group supplied with this product produced in one month more eggs and with bigger size.This increase in production was accompanied by changes in the bacterial community of the gut. Thesechanges in the microbiota suggest an improvement in food digestibility, as the most important changesproduced by these compounds occur in the most distal parts of the gut. The relative abundance ofbeneficial Lactococcus in the ileum and Lactobacillus in the cecum increased in the experimental group.Both genera are known to have beneficial effects on host. These results are very promising for the use ofthese compounds in poultry for short periods.Abstract: Phytobiotics (bioactive compounds extracted from plants) are one of the explored alternativesto antibiotics in poultry and livestock due to their antimicrobial activity and its positive effects ongut microbiota and productive properties. In this study, we supplemented a product based on garlicand onion compounds in the diet to laying hens at the beginning of their productive life (from 16 to20 weeks post-hatching). The experimental group showed a significant increase in the number of eggslaid and in their size, produced in one month compared to the control. This increase in production wasaccompanied by microbiota changes in the ileum and cecum by means of high throughput sequencinganalyses. These bacterial shifts in the ileum were mainly the result of compositional changes in the rarebiosphere (unweighted UniFrac), while in the cecum, treatment affected both majority and minoritybacterial groups (weighted and unweighted UniFrac). These changes in the microbiota suggest animprovement in food digestibility. The relative abundance of Lactococcus in the ileum and Lactobacillus inthe cecum increased significantly in the experimental group. The relative abundance of these bacterialgenera are known to have positive effects on the hosts. These results are very promising for the use ofthese compounds in poultry for short periods.