Gut health Colonisation of the intestinal tract by pathogens can reduce feed conversion rates and bird health in general, critically any infection can quickly spread within the flock. Pathogens rapidly multiply inside the gut in infected birds and are shed in the faeces in high numbers. This serves as a vector to spread the disease to the entire flock, thus infection of one begets infection of all. Using AGPs prevents colonisation of the gut in this way by eliminating pathogenic bacteria, AGPs also make the gut more hostile to infection by modulating the mucosal immune system. For example, Clostridia thrives in the mucus produced as a result of inflammation so con- trolling mucus production makes a large contribution to controlling infection. Considering beneficial bacteria, AGPs tend to target gram-negative bacteria as these are typically pathogenic. This allows gram-positive bacteria including beneficials like lactobacillus to take advantage and fully colonise the gut. Lactobacillus and similar bacteria increase synthesis of a wide range of beneficial metabolites which extends the microvilli in the intestine improving the uptake of nutrition from feed. The benefit shows in the feed conversion and


faster development rates in the flock. “Looking at what AGPs have given us, we can see there are two things we need to do to maintain current productivity in an antibiotic free system: Prevent infection and enhance gut microflora.”


Prevent infection “To prevent infection, you need to consider all the different ways that pathogens can be brought into the chicken house,” says Dr Richardson. “Water, feed, rodents, wild birds, insects, personnel, farm equipment and the young chicks them- selves are all potential vectors so biosecurity has to be im- proved all around. Without AGPs there is no final line of de- fence so pathogens have to be stopped before they get into the bird.” Birds consume 1.6-2 times more water per day than feed a day so if the water is contaminated, the flock will suffer from gut health problems and poor performance. The recom- mended maximum level of bacteria in drinking water target is 100cfu/litre. Big strides have been made in the industry in recent decades with the introduction of nipple waterers to replace trays or troughs where bacteria could proliferate. The main danger in modern systems is in the plastic pipework,


▶ POULTRY WORLD | No. 2, 2018


Colonisation of the intestinal tract by patho- gens can reduce feed conversion rates and bird health in gener- al, critically any infection can quickly spread within the flock.


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