Effect of oregano and its components on the morphometry and intestinal microbiota of broiler chickens: A meta-analytical approach.

• Grant number: 24/02281-1
• Support Opportunities: Regular Research Grants
• Start date: February 01, 2025
• End date: January 31, 2027
• Field of knowledge: Agronomical Sciences - Animal Husbandry - Animal Nutrition and Feeding
• Principal Investigator: Gustavo Do Valle Polycarpo
• Grantee: Gustavo Do Valle Polycarpo
• Host Institution: Faculdade de Ciências Agrárias e Tecnológicas. Universidade Estadual Paulista (UNESP). Campus de Dracena. Dracena , SP, Brazil
• Associated research grant: 23/12871-8 - Meta-analysis of the effect of oregan as a dietary additive for broiler chickens on growth performance and nutrient digestibility, AP.R

Abstract

Phytogenic additives are characterized as an alternative to enhance the efficiency of diets for broiler chickens by modulating the intestinal microbiome. Additionally, they have several other benefits, such as stimulating digestive enzymes and intestinal morphometry resulting in increased feed digestibility and productive performance. The use of oregano as a dietary additive seems promising; however, different evaluation conditions (heterogeneity among studies) result in inconsistent evidence. Oregano can be used in the form of plant extract (dehydrated and ground) or processed (e.g., aqueous extract or essential oil), may vary in quality, and be included in the diet at different doses, making interpretation difficult. Moreover, other factors that may interfere with the effectiveness of this additive include the sanitary condition in which the experiment is conducted, the genetics and physiology of the chickens, the composition of the feed, among others. At the same time, no meta-analysis work was identified that aimed to organize the subject. Therefore, the objective of this project will be to evaluate the effect of oregano as an additive in diets for broiler chickens on intestinal morphometry and microbiota through a meta-analytical study, identifying factors that may interfere with the results. Only scientific articles published in international journals will be analyzed, with searches conducted in the Scopus, PubMed, and Web of Science databases, aiming to minimize possible biases due to the use of only a single source of information. The main criteria for the selection of studies are: a) involvement of broiler chickens, b) supplementation of the diet with oregano and its essential oils thymol and carvacrol, c) results related to intestinal morphometry (measurements of villi and crypts in duodenum, jejunum, and ileum), and d) responses related to the composition of the intestinal microbiota (including different groups of microorganisms). Positive results are expected with the use of oregano and to identify the factors that explain the divergence of results in the literature, demonstrating the benefit of this additive in the nutrition and health of poultry. (AU)