Methodologies for selecting and characterizing plant extracts and evaluating their biological activities on the immunity of chickens

Abstract

The potential of plants known for their medicinal virtues is of great interest in a global context of reducing the risks of antibiotic resistance. In the context of animal nutrition, the use of plant extracts is part of an integrated management approach to animal health, with the aim of promoting immunity and limiting the onset of disease. The support of immune functions by the contribution of plant extracts is a way to reinforce the adaptation capacities of chickens, especially in the chick. To implement their use, this requires adapted and reliable complementary methodologies to ensure the quality and the functional added value of the extracts for the health of the chickens. The described steps, independent and complementary, allowed to elaborate and validate a global, relevant and robust methodology to select, characterize and evaluate the quality and the effects of plant extracts on the immunity of chickens in rearing situations. Analytical grids were gathered in a decision support tool (CHECK'MEX). Selected plant extracts such as lemon balm and ginseng were tested for their ability to stimulate innate immunity in poultry in cell models or in ex vivo models of inflammation and oxidative stress in chicken cells. The extracts were then evaluated in chickens under experimental conditions close to the field to validate their effects and to perform a multicriteria analysis including health, welfare and zootechnical indicators. This approach is applicable to all types of plant extracts and can be adapted for other animal species or other biological effects.