Simply removing antibiotics from a production system will lead to problems with bird health, mortality and product quality because of contamination or infections in the flock. However, there are several alternative management practices that can be used to prevent and eliminate such risks. Figure 1 below illustrates some potential sources of contamination on poultry farms. Improving biosecurity can dramatically reduce and even eliminate these sources.
Figure 1. Potential sources of contamination on poultry farms
Another consideration before starting an antibiotic free system is the quality of the day-old chicks used at the beginning of the production cycle. If the quality of the chick arriving on to the farm is compromised, antibiotics will be required to ensure the chicks survive.
Many antibiotic treatments have been, and still are being used to maintain intestinal health thereby ensuring efficient productivity. This can be achieved through low-level antibiotic inclusion for growth promotion, or in therapeutic doses to control disease. Either way, maintaining a healthy gut is the desired outcome. Most threats to gut health stem from outside the body. These are illustrated in Figure 2 below.
Figure 2. Threats to poultry gut health
Improvements in biosecurity at breeder farms and in the hatchery, result in very low bacteria numbers in the intestinal tract of chicks. And on farm, increasingly high standards of hygiene prevent the chicks being exposed to commensal bacteria. Therefore, the development of a healthy gut microflora in these chicks is more difficult and takes longer, jeopardizing production efficiencies. Probiotic supplements (PoultryStar®) administered at hatching and in the first days of life can overcome this shortfall in immune development.
A chicken will drink approximately two to three times the amount of water compared to the amount of food it eats, which reinforces the importance of this often forgotten nutrient. In developing countries, some poultry production farms rely on water from a well or bore hole to supply the houses. Contaminated water can be a major vector for the introduction of pathogenic bacteria into the house. The risks of coliform contamination in water from untreated sources is understood and management techniques should be employed to minimize such risk. Thorough cleaning of water lines and the addition of liquid acidifiers such as Biotronic® to maintain a low pH are two such techniques.
Some feed ingredients have a higher risk of carrying contamination than others, particularly in the case of salmonella. However, poor handling and storage practices could result in any ingredient becoming contaminated. Heat treatment through conditioning or pelleting can be used to positive effect on feed hygiene, however the results of these processes are not residual and the feed can become re-contaminated if poor handling and storage practices continue. Application of an acid mix product (e.g. Biotronic® Top3, or Top liquid) to the feed can overcome the risk of contamination to a reasonable degree, provided that sufficient product is used to meet the challenge. Applying the minimum amount of product will not prevent contamination if the risk is high.
Anti-nutritional agents can either be naturally present in the raw materials (e.g. non-starch polysaccharides in wheat) or through the incomplete heat treatments (e.g. trypsin inhibitors in soy bean meal). Such anti-nutritional agents can be avoided through close quality control of raw materials, and by using specific enzymes to neutralise them. Watch this video on how proper nutrition can reduce gut stress, and consequently allow for the reduction of antibiotic use, featuring Ellen van Eerden, researcher at Schothorst Feed Research.
Reduced digestibility of feed results in undigested nutrients passing to the hindgut where they can be utilised by pathogenic bacteria to develop, causing problems including clostridium perfringens and even necrotic enteritis. To help enhance the digestibility of feed, phytogenic products (e.g. Digestrom®) can be added. A recent survey carried out by BIOMIN revealed that the main reasons for including phytogenic products are improved feed efficiency and better microbial modulation. These two factors work synergistically as though the endogenous enzyme secretions of the small intestine were increased. More digestion by the animal means fewer nutrients available to the bacteria in the hind gut, resulting in a natural modulation of the bacterial populations.
Mycotoxins are present in all raw materials at differing levels depending on a variety of environmental and management factors. The most commonly occurring mycotoxins are fumonisins, of which trichothocenes and zearalenone are the most common. The BIOMIN Mycotoxin Survey regularly identified deoxynivalenol (DON) and fumonisin B1 (FUM) as the most common mycotoxins contaminating feedstuffs and raw materials in thousands of tests carried out globally. DON and FUM are known to have detrimental effects on gut integrity through various mechanisms. (Read How Mycotoxins Aggravate Coccidiosis in Poultry). Therefore, regular monitoring of the mycotoxin levels in raw materials and finished feeds is advisable. The inclusion of a suitable mycotoxin deactivator (Mycofix®) at the correct inclusion levels will help to manage any potential contamination.
In some countries, ionophore coccidiostats are not permitted in diets if the producer wants to achieve antibiotic-free status. In such cases, vaccination with anti-coccidial vaccines is practiced. Research has shown that where vaccines are used, synbiotic products (PoultryStar®) can enhance the anti-coccidial effects of the vaccines.
As seen, there are several levers of gut health that need to be considered, monitored and managed by the poultry producer. But there are also several feed additives that can be used to overcome these challenges. The feed additives offered by BIOMIN all complement each other and work together to facilitate antibiotic-free production.