PHOTO: REWAT WANNASUK
β-glucans: Effective antibiotic alternative
BY MATTHEW WEDZERAI, INDEPENDENT CORRESPONDENT N
ot only in poultry alone is the effort to reduce the use of antibiotics important but cross all animal species and feed industries, scientists are battling a worthy battle to reduce the use of antibiotics. We
all know the occurrence of microbial challenges in commer- cial poultry farming causes significant economic losses. But the incidence of antibiotic resistance turns out to be a bigger challenge putting pressure on producers to reduce antibiotic use. Reducing antibiotic use should come with alternatives. With this reality at hand, poultry producers are looking for feed additives to stimulate the immune system of the chicken to resist microbial infection. β-glucans are effective alterna- tives. But how? In a recent publication in Molecules, research- ers elaborate the potential benefits of β-glucans as poultry feed additives.
What are beta glucans? β-glucans are carbohydrates (or biologically active fibres) made of complex glucose polymers that provide the major structure found in the cell wall of yeast, fungi, algae, and cereal grains such as oats and barley. The structures of β-glucans vary depending on the original source and the type of linkages present on the glucose polymers (Figure 1). β-glucans consist of a backbone of glucose molecules linked at the 1 and 3 carbon atoms. The six-sided glucose rings are connected in linear or branched forms with glycosidic linkages. The structure of these glycosidic linkages affects the functionality of β-glucan molecules. Depending on their molecular structure, they are considered a biological response modifier due to their immunomodulatory potential. β-glucans are recognised by specific cell receptors, enabling them to enhance the host’s immune response. The β-glucans from yeast, S. cerevisiae, are the most widely studied. This yeast is responsible for the fermentation processes in the production of fuel alcohol, breads, and alcoholic beverages.
Enhance immune system The researchers reviewed several benefits of β-glucans to the poultry immune system. Yeast β-glucan supplementation in broiler chickens results in larger lymphoid organs, the organs that produce lymphocytes — precursor cells for both the adaptive immune system and for the natural killer cells. In
Researchers unveil how β-glucans hold the potential as alternatives to the use of antibiotics in poultry production. The beneficial properties of β-glucans behind the efficacy are elaborated.
chicks, β-glucans increases phagocytosis (bactericidal killing), and oxidative burst in heterophils. β-glucans derived from the yeast S. cerevisiae have demonstrated to exert the most significant positive effect. β-glucans stimulates macrophage production and proliferation of T cells. In broilers, they upregulate the enzyme iNOS (nitric oxide synthase) intestinal expression, implying the increased capacity of intestinal macrophages to destroy pathogens. The down regulation of cytokine IL-8 following β-glucan supplementation in chicks suggests the function of β-glucan as an anti-inflammatory immunomodulatory agent. β-glucans also have protective effects against stress in chickens as seen by decreased levels of cortisol and TNF-α following an LPS challenge. In chickens, the spleen serves both as a reservoir of leukocytes as well as a target organ of immune cells activation. Feeding β-glucan in broilers significantly increases the relative weight of the spleen.
Improves GIT health According to the researchers, β-glucans modulate the intestinal profile of cytokines in broiler chickens, activating the production of monocytes and macrophages, resulting in
▶ ANTIBIOTIC REDUCTION | DECEMBER 2021 27
β-glucans are potential growth promoters and antibiotic alternatives in poultry production.
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