The use of probiotics as eco-friendly alternatives for antibiotics in poultry nutrition

Probiotics are gaining more and more interest as alternatives for antibiotics or anti-inflammatory drugs. However, their mode of action is poorly understood. This review will present examples of probiotic actions from three general modes of actions into which probiotic effects can be classified. Probiotics might modulate the host's immune system, affect other microorganisms directly or act on microbial products, host products or food components. What kind of effect(s) a certain probiotic executes depends on its metabolic properties, the molecules presented at its surface or on the components secreted. Even integral parts of the bacterial cell such as its DNA or peptidoglycan might be of importance for its probiotic effectiveness. The individual combination of such properties in a certain probiotic strain determines its specific probiotic action and as a consequence its effective application for the prevention and/or treatment of a certain disease. Copyright 2009 Elsevier GmbH. All rights reserved.

The increase of productivity in the poultry industry has been accompanied by various impacts, including emergence of a large variety of pathogens and bacterial resistance. These impacts are in part due to the indiscriminate use of chemotherapeutic agents as a result of management practices in rearing cycles. This review provides a summary of the use of probiotics for prevention of bacterial diseases in poultry, as well as demonstrating the potential role of probiotics in the growth performance and immune response of poultry, safety and wholesomeness of dressed poultry meat evidencing consumer’s protection, with a critical evaluation of results obtained to date.

Probiotics are defined as live microorganisms that, when administered in adequate amounts, confer a health benefit on the host, including the gastrointestinal tract. While this beneficial effect was originally thought to stem from improvements in the intestinal microbial balance, there is now substantial evidence that probiotics can also provide benefits by modulating immune functions. In animal models, probiotic supplementation is able to provide protection from spontaneous and chemically induced colitis by downregulating inflammatory cytokines or inducing regulatory mechanisms in a strain-specific manner. In animal models of allergen sensitization and murine models of asthma and allergic rhinitis, orally administered probiotics can strain-dependently decrease allergen-specific IgE production, in part by modulating systemic cytokine production. Certain probiotics have been shown to decrease airway hyperresponsiveness and inflammation by inducing regulatory mechanisms. Promising results have been obtained with probiotics in the treatment of human inflammatory diseases of the intestine and in the prevention and treatment of atopic eczema in neonates and infants. However, the findings are too variable to allow firm conclusions as to the effectiveness of specific probiotics in these conditions.