“STRATEGIES EXIST FOR COPING WITH POOR QUALITY GRAIN: PART 3”
In the previous two issues of Milwhite’s Journal information was presented that identified the various enemies of grain during storage and how to prevent damage from occurring to stored grain by implementing a quality control program within a poultry company and/or feed mill. Discussed were strategies for storing good quality grain as well as poor quality grain and how to maintain the quality of the good quality grain during storage by maintaining a proper storage silo environment. In this third and final part of this series about grain quality and its storage, strategies are presented that will assist poultry companies in minimizing the damage to their birds when forced to make decisions relating to having to use poor quality grain in feed formulation.
MINIMIZING THE DAMAGE TO POULTRY PERFORMANCE CAUSED BY FEEDING POOR QUALITY GRAIN
It is not possible to produce high quality feed with poor quality ingredients. The most obvious way to prevent poor quality grain, such as that contaminated with mycotoxins, from causing problems with poultry performance and health is to never use the grain in feed formulation. Avoidance is considered one of the best methods of protection against mycotoxins. However, in most cases, avoidance is impossible or impractical. This is especially true in countries that depend on imported grains to sustain their intensive animal industries, especially the poultry industry. Using poor quality grain will mean that a company must implement a specific plan for its use in order to minimize the damage that it will have on the health and performance of their birds.
If mycotoxins exist in grain then the first step taken in order to minimize mycotoxin damage to poultry flocks is to have the ability to quickly and reliably determine the presence of specific mycotoxins in incoming grain so decisions can be made to accept or reject the grain. Of course, any mycotoxin analysis is only as good as the sampling technique used to obtain a representative grain sample. Reliable procedures to follow when sampling grain exist and should be used each time samples are taken. Despite what some people think, It is not possible to correlate the number of mold counts in grain with the actual amount of mold and/or mycotoxin present since mold spore counts only provide an indication of the degree of sporulation that has occurred and not the actual amount of mold present. Today, using mycotoxin test kits is a reliable way to screen for mycotoxins. It is possible to have a high mold count without the presence of high concentrations of mycotoxin. Pelleting of a formulated feed is known to kill bacteria and mold and will also decrease viability of many mold spores, but mycotoxins will persist in pelleted diets. No amount of mycotoxin is safe and no universal recommendation is applicable for all mycotoxins. Knowing which specific mycotoxin is present is essential because a recommendation made to divert contaminated diets among different species of animals in an attempt to minimize damage from one mycotoxin may not necessarily work for another mycotoxin. For example, poultry are extremely sensitive to the adverse effects of aflatoxin (E.g., B-1) whereas beef cattle are more tolerant just as poultry are more tolerant of the estrogenic effects of zearalenone than swine.
MOLD INHIBITORS/BINDING AGENTS
If a decision is made to use poor quality grain a poultry company puts itself in a defensive situation since it has to implement ways to minimize the damage that the grain will cause in flock performance and health. One recommendation would be to use feed additives such as organic acids and approved mold inhibitors that inhibit any further mold growth. This should be followed by a plan to continually monitor the grain on a regular basis for mold growth and keeping in mind that these feed additives have no effect on reducing the concentration of mycotoxins already present in the stored grain. If mycotoxins are present then the use of binding agents is justified and there are many such agents available for use in the mixed feed. Selecting the correct binder is very important since some agents bind certain mycotoxins better than others and there is presently no binding agent that will bind all mycotoxins once it is in the gastrointestinal tract. Also, it must be remembered that just because a mycotoxin binder is effective at binding in-vitro does not mean that it will be effective in-vivo. This means that at a sales meeting when companies are showing mycotoxin binding ability of their binding agent the poultry companies should always, without exception, demand to see how effective the agent is in binding mycotoxins at the point of use, which is in the animal’s gastrointestinal tract.
STRESSORS AND PROPER NUTRITION
It is possible to minimize the amount of damage that mycotoxins, especially low levels, exert on bird performance by minimizing the number and intensity of stressors to which the birds are exposed within the chicken house. This is accomplished by using good management and also providing the bird with the best nutrition possible when it is known that mycotoxins are present. Mycotoxins are known to target the immune system which results in immunosuppression and the amount of mycotoxin required to depress the immune system has been shown to be much less than that required to observe a negative effect on animal performance. Research data in the scientific literature have shown that there is a definite link between a healthy, non-stressed bird receiving a properly formulated diet and its ability to cope with mycotoxins. Birds and other animals have enzymatic systems in their bodies, especially the liver, which are capable of detoxifying mycotoxins. However, nutritional deficiencies compromise these systems and also compromise the animal’s immune system.
Once a company categorizes grain quality as good or poor a decision has to be made concerning how the grain can be used to minimize damage to performance and health. Every company should establish a mycotoxin tolerance scale that can be used to allocate the contaminated grain within their poultry operation. The mycotoxin concentration range of the scale should be associated with the bird’s age and the purpose of the bird within the company. A broiler breeder, broiler and a commercial egg-type laying hen each have different tolerances for different mycotoxins. High quality grain should be used in diets of broiler breeders of all ages and young growing broilers less than three weeks of age. For example, research studies have shown that older broilers and mature commercial egg-type laying hens are more tolerant to aflatoxin B-1. A company’s tolerance scale for aflatoxin B-1 could possibly be divided into concentration ranges of from 0 to 20 ppb, 20 to 100 ppb, 100 to 1,000 ppb and more than 1,000 ppb. Once such a scale is developed decisions by the company can be made regarding the allocation of the grain to the appropriate birds or other animals such as ruminants since they are less sensitive to mycotoxins. Of course, one of the safest ways to be sure that birds are protected from the negative effects of mycotoxins is to use a proven binding agent. In the above “scale scenario” aflatoxin B-1 was used only as an example and this type of scale should be established for each of the most important mycotoxins with which the company may be confronted. When multiple mycotoxins are present it becomes very difficult to implement a program to completely control the damage that each mycotoxin and their interactions will have on bird performance. However, in such cases, every attempt must be made to decide which mycotoxin(s) will likely cause the most damage and use every possible method available to minimize their detrimental effects.
If the mycotoxin concentration is known and the grain has been stabilized so that mold growth is not occurring a decision could be made to decrease the percentage used in the formulation in an attempt to obtain a final concentration in the diet lower than 20 ppb, for example. This is not considered grain blending, which is no longer recommended. In the 1970’s blending contaminated grain with higher quality grain was a common practice. However, it was quickly discovered, that instead of simply diluting out the negative effects of the mycotoxins found in the contaminated grain, the mold in some cases was actually contributing to the rapid deterioration of the good quality grain.
Nutritionists play an important role in minimizing the damage that mycotoxins may have on poultry performance by making dietary adjustments. In the August, 2016 issue of Milwhite’s Journal all of the nutritional adjustments that are commonly made to a diet contaminated with mold and mycotoxins are discussed. It is hoped that the information in this issue and the two previous issues of Milwhite’s Journal shows how important it is for a poultry company’s feedmill manager, quality control personnel, veterinarians, production managers and nutritionists to work together as a team in order to establish and follow company guidelines for their incoming grain and other feed ingredients so as to provide their birds with the best quality feed available.