If severe inflammation occurs in the gut it has a negative effect on animal performance, because it tells the gut to stop absorbing nutrients – making more nutrients available to bacteria. It does this by breaking the bond between the 2 sugars that make up the backbone of peptidoglycan. Muramidases are enzymes that can breakdown PGN, forming muramyldipeptide (MDP). But a bird with a high feed intake like a broiler cannot make enough lysozyme to breakdown the amount of PGN present in its gut. For example, lysozyme is an endogenous enzyme that can break down PGN, hydrolysing the cell wall of the bacteria and killing it. In the gut, PGN recognition proteins bind to PGN and are able to cleave the molecule into smaller pieces. They can help to modulate the host’s immune system when pathogens are present, with some having an antibacterial effect. Enzymes for gut healthĮnzymes produced in response to infection are the cornerstones of innate immunity. In return animals can take advantage of the nutrients bacteria produce including B vitamins and short chain fatty acids like butyrate and propionate. Here they multiply and feed on the indigestible parts of plant cell wall, such as polysaccharides. In fact, the environment supports them to do so, creating a symbiosis between microbes and host.
Once in the caeca, in the case of birds, the bacteria recover. Here the flow of digesta is relatively fast to prevent recovery of the bacteria before they reach the large intestine. They pass to the small intestine, where the nutrients from the feed can be absorbed by the bird. This means that they can no longer take up nutrients intended for the host animal. The acidic environment of the stomach kills certain bacteria, whilst putting others into a dormant state where they are no longer metabolically active. Photo: DSMĪll animals are taking in microbes constantly from their food and the environment – the gastrointestinal tract has evolved to cope with this normal threat. – scouring and vomiting to quickly expel pathogens).īalance in inflammatory responses means a healthy gut and increases efficiency. If it needs to be increased in response to a threat from pathogens, it is easier to do so from that position (e.g. Even animals in the best of health always have some inflammation in their gut. This is due to intestinal inflammation reactions PGN may trigger by binding to the epithelial receptor TLR2. Bacterial cell wall fragments present in the gut, including PGN, can impact nutrient digestion and absorption. But in commercial broiler production, damage to the intestine is inevitable. In a healthy gut, tight junctions are maintained, and pathogens can’t move through the gut barrier. Gram-positive bacteria have a thick outer layer of PGN, whilst gram-negative bacteria have a thinner PGN layer in between the inner and outer membrane that is covered by lipopolysaccharides ( Figure 1). Figure 1 – PGN is present in the cell walls of both Gram- and Gram+ bacteria.īacterial cells are protected by several layers including membranes, lipopolysaccharides, proteins and peptidoglycans (PGN). Proteases and lipases on the other hand, support and reinforce the action of the bird’s own digestive enzymes to break-down protein and fat. Carbohydrases – like xylanases, gluconases, furanosidases – degrade non-starch polysaccharides, allowing the animals to obtain more energy and/or nutrients from their diet. Phytases are enzymes that enhance the release of phosphorus and trace minerals from plant phytate. Phytases, carbohydrases, lipases and proteases – as well as increasing the nutritional value of feed – help prevent the negative effects of anti-nutritional factors in raw materials. The practise of adding enzymes to poultry feed is virtually an industry standard.
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