A trial was conducted to evaluate the efficacy of essential oil supplementation on laying hen egg production and quality, and gut health. Fifty-four Lohman LSL-Classic laying hens were randomly assigned to 3 treatments and provided different levels of a liquid essential oil blend containing Citrus, Oregano, and Anis oils in drinking water from 31 to 39 weeks of age. Hens received a control treatment (no essential oils), essential oils level-1 (30 ml per 1000 ml of water), or essential oils level-2 (60 ml per 1000 ml of water). The layer diet was formulated according to the specifications listed in the nutrition guidelines of Lohman LSL-Classic and fed throughout the experimental period. Each of the 3 treatments had 6 replicates of 3 hens each. Data were analyzed as a one-way ANOVA using the GLM procedure. No significant differences were observed in egg production data between the groups. Heavier egg weights (P<0.01) were observed in the control treatment followed by level 2 and then level 1 for weeks 1 and 3. However, egg weight was heavier (P<0.0001) for levels 2 and 1 compared to the control treatment at week 4. No significant difference were observed for shell thickness. Haugh units were higher (P<0.01) for level 2 compared to control and level 1 at week 4. At the end of the study, jejunum villi length and crypt depth were higher (P<0.01) for levels 2 and 1 compared to the control treatment. There were no significant differences among ileum measurements or blood chemistry parameters at any point during the experiment.
Based on these results, it was concluded that adding essential oils to drinking water positively improved jejunum histology and resulted in heavier egg weights in Lohman laying hens.