An Introduction to the Avian Gut Microbiota and the Effects of Yeast-Based Prebiotic-Type Compounds as Potential Feed Additives

Abstract

The poultry industry has been searching for a replacement for antibiotic growth promoters in poultry feed as public concerns over the use of antibiotics and the appearance of antibiotic resistance has become more intense. An ideal replacement would be feed amendments that could eliminate pathogens and disease while retaining economic value via improvements on body weight and feed conversion ratios. Establishing a healthy gut microbiota can have a positive impact on growth and development of both body weight and the immune system of poultry while reducing pathogen invasion and disease. The addition of prebiotics to poultry feed represents one such recognized way to establish a healthy gut microbiota. Prebiotics are feed additives, mainly in the form of specific types of carbohydrates that are indigestible to the host while serving as substrates to select beneficial bacteria and altering the gut microbiota. Beneficial bacteria in the ceca easily ferment commonly studied prebiotics, producing short-chain fatty acids, while pathogenic bacteria and the host are unable to digest their molecular bonds. Prebiotic-like substances are less commonly studied, but show promise in their effects on the prevention of pathogen colonization, improvements on the immune system, and host growth. Inclusion of yeast and yeast derivatives as probiotic and prebiotic-like substances, respectively, in animal feed has demonstrated positive associations with growth performance and modification of gut morphology. This review will aim to link together how such prebiotics and prebiotic-like substances function to influence the native and beneficial microorganisms that result in a diverse and well-developed gut microbiota.

Effects of Acidified Yeast and Whey Powder on Performance, Organ Weights, Intestinal Microflora, and Gut Morphology of Male Broilers

“…Gao et al (2008) reported that growth performance and immune modulatory functions improved in broilers fed with yeast product. It has been shown that yeast product contains beneficial nutrients such as peptides, oligosaccharides, flavors and aroma substances which increase nutrient digestibility, enhance the growth of beneficial bacteria such as Lactobacillus and improve gut immunity against pathogens (Roto et al, 2015). Adil et al (2010) supplemented broiler diets with various levels of different organic acids to evaluate the effects of acidifiers on productive performance and gut morphology.…”

“…The beneficial effects of yeast, whey and acidifiers as growth promoters and immune enhancers have already been demonstrated (Gao et al, 2008;Szczurek et al, 2013;Ricke, 2003). For example, yeast product, which contains high amounts of mannan chains (Roto et al, 2015), is a basic component of some commercially available prebiotics and has been shown to improve body weight gain, feed conversion ratio and immune response in broilers (Gao et al, 2008). Whey, another known additive that is a source of different nutrients such as proteins and carbohydrates (Szczurek et al, 2013) is also a source of lactose.…”

Getting Better Intestinal Health through the Addition of Yeast (Saccharomyces Cerevisiae) Combined with Threonine in Broilers Diets

“…They are mainly carbohydrates that are indigestible to the host, are selectively fermented by beneficial microbiota in the gut, so as to provide energy to promote bacterial growth and metabolism in the colon. These contribute to specific changes that lead to improved host health (Roto et al, 2015;Maynard et al, 2012). Prebiotics act under different mechanisms, whose depends on the nature of the compound.…”

“…Sc is used as a feed additive in avian production because it is a rich source of protein, fiber, and minerals, provides essential B vitamins (biotin, niacin, pantothenic acid and thiamin and its biological value is high) and organic acids (Adebiyi et al, 2012;Roto et al, 2015), resulted in increased growth and improved health in broilers (Miazzo et al, 2001(Miazzo et al, , 2010Zang et al, 2005;Hosseini, 2011;Adebiyi et al, 2012;Roto et al, 2015).…”

“…The fermentation of Sc produces yeast cell wall fragments and residual live yeast cells or their extract; thus, Sc share characteristics in both probiotic and prebiotic (Li et al, 2006;Gao et al, 2008;Haldar, 2011;Roto et al, 2015).…”