The Influence of Dietary Supplementation with Dried Olive Pulp on Gut Microbiota, Production Performance, Egg Quality Traits, and Health of Laying Hens

This study examines the dietary effect of dried olive pulp (OP) on the overall performance, egg quality, health, and gut microbiota of laying hens during a 36-week trial. A total of 180 Isa Brown layers, aged 23 weeks, were assigned to 15-floor pens and divided into three feeding groups (CON, OP4, and OP6) based on the dietary level of OP. Egg quality and biochemical parameters were assessed in 39- and 59-week-old hens. Fecal samples were collected for microbiota analysis. Data were analyzed with an Analysis of Variance. The percentage of broken eggshells was found to be 15-34% lower in the OP groups compared to the CON groups. At 59 weeks of age, a significant reduction in shell thickness was observed in the CON eggs compared to the OP eggs (<i>p</i> < 0.05). At 39 weeks of age, OP6 eggs had the darkest yolk color of all groups (<i>p</i> < 0.05). Fecal microbial diversity was affected only by hens' age. However, an enrichment in bacterial species belonging to the genera <i>Megasphaera</i> and <i>Megamonas</i> was found in the OP groups at 59 weeks of age. Our results demonstrate that OP feeding beneficially affects egg quality and promotes the proliferation of bacteria involved in the degradation of complex plant compounds, potentially contributing to the overall health of the gut microbiota.