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harmful biofilms can build up, which act as nucleus for infec- tion to be spread by water. “Poultry farmers should look to effective water sanitisers to keep biofilms in check. To maximise biosecurity, do a full clean of pipework and drinking equipment between flocks and check the hygiene of the original water sources if you are not drawing off the mains supply. “Compared to water, biosecurity with feed is a bit more com- plicated, for starters there is no agreed benchmark for a safe level of bacteria in feed although Anitox has years of data showing fewer bacteria results in better performance across the board. But like in-coming chicks, feed must be consid- ered as a critical control point in any well designed, compre- hensive biosecurity programme, i.e. feed is delivered to every farm multiple times throughout the grow-out cycle, and is consumed by every bird. If a pathogen is in the feed, even at very low levels, there is a very good chance that the birds are going to find it.”
Feed treatment With feed, you need to consider what happens in the feed mill but also how it is stored and transported. On farm, there are basic steps like keeping stores and silos secure from ver- min and water penetration but the challenge is at the micro- biological level. The first question is how clean is the feed coming from the feed mill? Heat treatment is the most common method for controlling bacteria in the mill. When done with the correct duration (several minutes), it is very effective at reducing bacteria but not all mills have the capacity to heat treat for long enough as it may cause a backlog. The other thing is that heat treat- ment offers no residual protection hence, feed can be
Physical biosecurity and gut health
In addition to feed, water and stock – poultry farmers need to consider the envi- ronmental challenges at the farm. It will require upgrading older equipment, put- ting the right hygiene protocols in place and backing it up with good staff train- ing. The breeding and turkey sector have already implemented better biosecurity at the farm, “no antibiotic ever chicken” means the broiler producer is going to have to close this gap. “Once you’ve taken the right biosecurity steps for in-com- ing chicks, water, feed and the environment, the other part of the challenge is to promote beneficial bacteria,” says Kurt Richardson. “Chicks receive some microflo- ra by maternal transmission but it takes around three weeks to reach homeosta- sis – during this time in particular farmers should to support the development of the gut microflora.” There are several supplements claiming to improve gut health. The most common are prebiotics and probiotics. Prebiotics are nutrition for gut microflora whereas probiotics are the beneficial bacteria themselves. Dr Richardson believes that both pre- and probiotics will play a useful supporting role in broiler production but that biosecurity, particularly of feed and the environment, is likely to be most important for production without antibiotics.
22 ▶ POULTRY WORLD | No. 2, 2018
re-contaminated by bacteria the second it leaves the pellet die. Sometimes this is not necessarily a high challenge prob- lem if the feed is going to be consumed without a long delay but on farm feed is often left in silos and hoppers for days so bacteria can multiply to high numbers. Other common options for feed treatment, including irradia- tion and organic acids, also lack residual protection which raise questions over their value for antibiotic free produc- tion. “Short chain organic acids are great for water treatment but the evidence for feed is hit and miss. Efficacy varies and we don’t have a good handle on why,” explains Dr Richard- son. “Anyone looking at organic acids as a direct replacement for AGPs will be disappointed – at high levels they are good bactericide but they don’t keep the feed clean and I’m not convinced that they have any benefits to the function of gut microflora because the shorter chain acids are broken down by the time they reach the intestine. “With feed, I would look to the provide the best protection against bacteria and then look to manage the gut microflora with other products. A treatment like Termin-8 has proven superior kill activity with significant residual control of bac- teria for greater than 14 days, this gives producers the best chance to keep the microbiological burden low and help with antibiotic free production.”
Grey areas Another thing to keep in mind is that the birds themselves can also be a carrier for bacteria if they come from breeder houses with existing disease problems. In fact, breeders are a big part of the antibiotic free production picture. Breeders obviously have a longer production cycle than broilers, are usually on very restrictive diets in the pullet cycle, and under stress during the lay cycle so are more at risk of colonisation by pathogens for much longer meaning antibiotics are very important for disease prevention. According to Dr Richard- son whether antibiotics will still be widely used in breeders is not clear. Breeders aren’t the only question; the definition of antibiotic is not fixed. For Dr Richardson, whether ionophore anti-coc- cidials also face restrictions in antibiotic free production is a big concern: “Coccidial protozoa are like the artillery which weakens the gut defences and then clostridia follow up – if ionophore anti-coccidials are also restricted then I believe dealing with clostridium is going to be a lot tougher.” “In Europe the indication is that ionophore anti-coccidials will be restricted so we need to see how that plays out.” On the question of Europe, Dr Richardson has sobering thoughts for anyone who believes that antibiotic free is going to be easy. “When Europe ruled out AGPs, therapeutic use rocketed – the legislation made no real difference to usage of antibi- otics just to how they were classified. However, I don’t think that is going to be the case in other markets and Europe is likely to become more stringent on therapeutic use too.”
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