DOSAGE AND DURATION OF ADMINISTRATION

The effectiveness of probiotics in supporting poultry health and immunity depends heavily on the dosage and duration of administration [80]. Appropriate dosing is crucial for stabilizing beneficial microbial populations in the digestive tract, enabling them to compete with pathogens, produce bioactive metabolites, and effectively modulate the immune system [216]. Dosage is typically determined by the type of probiotic, the age of the poultry, environmental conditions, and the intended purpose, such as enhancing growth, strengthening mucosal immunity, or improving the response to vaccination [217].

The duration of probiotic administration also plays a significant role [218]. Short-term administration may be sufficient to trigger a temporary immune response, but long-term supplementation has been shown to be more effective in establishing a stable gut microbiota balance, increasing mucosal antibody (IgA) production, and strengthening innate and adaptive immunity [219]. Research shows that administering probiotics early in life in birds can stimulate the development of lymphoid organs, such as the bursa of Fabricius, thymus, and spleen, thus supporting optimal immune system maturation [220].

Furthermore, administering probiotics at too low a dose may have only a minimal effect, whereas administering too high a dose does not always confer benefits and can disrupt the microbiota balance [221]. From a cost–benefit standpoint, identifying the minimal effective dose is essential to avoid unnecessary product expenditure without proportional performance gains. Non-linear dose–response patterns suggest that increasing dosage beyond the optimal threshold may increase cost without improving biological outcomes [222]. This approach aims to ensure probiotics provide optimal benefits in improving health, disease resistance, and sustainable poultry production performance [223].