Inclusion of lemon balm (Lippia alba) as a phytogenic additive in the diet of Japanese quail

Abstract

Japanese quail is a small bird with a short production period. However, the use of performance-enhancing antibiotics can leave residues in its meat and eggs. As an alternative, phytogenic additives can be used to cultivate beneficial bacteria in the gastrointestinal tract, improving the digestion and absorption of ingested nutrients. This study aimed to evaluate the effects of adding different concentrations of lemon balm as a phytogenic additive on the performance, egg quality, and differential leukocyte count of Japanese quail raised in the semiarid region of Brazil. The experiment was conducted in the poultry sector of the Paraíba Institute of Science and Technology – Sousa-PB campus, from June to September 2022. Eighty Japanese quail, 80 days old and standardized by production and body weight, were utilized. The design was completely randomized with four treatments and four replicates, each containing five birds per plot. The experimental period was 88 days, consisting of four 22-day cycles. Dried lemon balm was incorporated as a phytogenic additive in the birds' diet at concentrations of 0, 0.3, 0.6, and 0.9%. Performance variables and egg quality were assessed. Regression analysis was conducted for statistical analysis using SAS software. To determine the differential leukocyte count, two blood samples were collected and analyzed with blood smears. The leukocyte counts underwent analysis of variance and Tukey's test, at a significance level of 5%, using the statistical program R. A significant decreasing linear effect was observed for feed conversion per dozen eggs, as well as a quadratic effect for conversion per egg mass. Albumen height showed a significant quadratic effect, and there was a decreasing linear effect on albumen percentage. Additionally, a quadratic effect was noted for Haugh Unit. The inclusion of lemon balm had a positive effect on feed conversion per dozen eggs and enhanced albumen height, suggesting a requirement of 0.501% for optimal results, as well as on yolk color, which showed an intensified shade with increased herb inclusion. The Haugh Unit also demonstrated a significant effect, with an optimal concentration of 0.495%. The use of 0.5% dried lemon balm (Lippia alba) is recommended as a phytogenic additive for Japanese quail in the laying phase. The addition of different concentrations of dried lemon balm did not influence the differential leukocyte count or the heterophil:lymphocyte ratio of Japanese quail in the semiarid region.