IMPROVED MILBOND-TX® “ASSISTING POULTRY NUTRITIONALLY IN THE PRESENCE OF MOLDS AND MYCOTOXINS”
There have been tens of thousands of publications which have detailed the negative effects that mycotoxins have on survivability and performance of poultry and other animals since the term “mycotoxin” was first used in 1962 to describe the reason for the death of approximately 100,000 turkey poults near London England. During the past 60 years, because of the highly toxic nature of mycotoxins in humans and domesticated animals, a tremendous amount of fundamental information has been learned about the molds (fungi) that produce specific mycotoxins and their mechanisms of action which are directly responsible for their lethal effects at the cellular level. We now know that the mechanism of the most toxic mycotoxins is a direct interference with DNA, RNA and protein synthesis within all body cells. Since mycotoxins are produced by various species of fungi, one of the best ways to prevent mycotoxin contamination is to prevent the growth of molds on foodstuffs, especially grains, which are a major source of nutrients and energy required for mold growth. Controlling the moisture content of grains post-harvest is essential if mold growth and subsequent mycotoxin synthesis is to be prevented. Also, there are several products available to the animal feed industry which are very effective in preventing mold growth in stored grain and mixed feed. The most common of these products are the organic acids, especially propionic acid. The organic acids will only inhibit mold growth, but will not have any effect on the mycotoxins already present. Stopping any further mold growth is the first step that should be taken.
If mycotoxins are already present in animal feed there are numerous commercially available products that are beneficial in preventing the devastating effects of mycotoxins. One of the most common approaches today, which is used world-wide, to prevent the negative effects mycotoxins have on animal performance is to use mycotoxin binders. These binders are added to the feed and will adsorb (bind) specific mycotoxins and prevent their absorption into the body from the digestive tract. Previous issues of Milwhite’s Journal have addressed the efficacy of various binders used by the animal industry, especially the safety and effectiveness of Milbond TX® against Aflatoxin B-1 (AFB-1). If molds and mycotoxins are present in feed there are certain nutritional recommendations which have been shown to be beneficial in assisting poultry in coping with them. A decrease in feed intake is common when mold(s) and/or mycotoxin(s) contaminate feed. In this case, a universal recommendation often followed by nutritionists is to simply increase the nutrient density of the diet to help restore nutrient intake. In such situations feeding high quality, highly digestible feed ingredients will assist the bird greatly. Bird performance may not be fully restored, but increased nutrient intake and consuming high quality ingredients will help the bird to cope with the mold and mycotoxins. Knowing specifically which mycotoxin is present in the feed is very valuable information since certain nutritional recommendations are more effective against specific mycotoxins. The following is a brief summary of the nutritional recommendations that have been reported in the scientific literature as being beneficial, especially to poultry.
MOLD GROWTH AND RECOMMENDATIONS: Molds are heterotrophic organisms, just as all animals, protozoa and most bacteria are heterotrophic. Heterotrophs are not able to synthesize their own carbon-based food as autotrophs (i.e., plants) are able to do. Therefore, heterotrophs require preformed complex organic molecules present in plants and animals, to supply their nutrients and energy. A result of mold growing on grain is lower crude protein (CP) and metabolizable energy (ME) values of the grain and nutritionists must take this into consideration when formulating diets. Data collected with grain (especially corn) moderately infected with mold have shown that contaminated grain contains approximately 5% less protein and 10% less ME. For example, if uncontaminated corn had a value of 8% CP and 3,300 Kcal ME/Kg for poultry the values, because of mold damage, would be lower (i.e., 7.6% CP and 2,970 Kcal/Kg ME). Adjusting the computer program’s ingredient matrix CP and ME values for the grain will assist the nutritionist in meeting their requirement for poultry. Of course, experienced nutritionists would more than likely use their own values for adjusting the amount of a specific grain’s CP and ME.
Recently, (Chen et al. 2016, reference cited below) presented data showing that a high protein diet (26% CP) fed to broiler chicks from hatch to 20 days of age was able to completely prevent the detrimental effects that feeding a diet containing 1.5 mg/kg AFB-1 had on performance, nutrient digestibility and gut health. Feeding a diet containing 16 or 22% CP did not overcome the detrimental effects of AFB-1. Even though previous studies have shown that supplementing high protein and certain amino acids are beneficial to broilers fed diets containing AFB-1, this intensive study provided more detailed data on how a high protein diet assisted broiler chicks in overcoming the detrimental effects that AFB-1 had on overall intestinal anatomy and function, intestinal transporters, gut barrier/tight junction integrity, components of serum biochemistry, nutrient digestibility and breast meat yield.
OTHER RECOMMENDATIONS: When AFB-1 is the dietary contaminant an effective recommendation which will assist the bird nutritionally to minimize damage caused by AFB-1 is to supplement the diet with more synthetic methionine (e.g., 120-150% of requirement). Extra methionine will stimulate the synthesis of cysteine which is an amino acid essential for synthesis of the tri-peptide known as “glutathione (GSH)” which contains cysteine, glycine and glutamic acid. In the liver GSH binds with a very toxic metabolite of AFB-1 known as “AFB-1-8, 9 epoxide which is highly reactive and responsible for causing cellular damage at the level of DNA and RNA.
The GSH/epoxide complex forms “mercapturic acid” which is non-toxic and eventually excreted via urine and bile.
Supplementing 0.1% more choline to poultry diets has been shown to be effective with AFB-1 contamination. The extra choline will assist in moving lipid from the liver since AFB-1 is a hepatotoxin that injures the liver and interferes with lipid transport from the liver. Decreasing the lipid content of the diet when the fusarium toxin, diacetoxyscirpenol (DAS), is present has been shown to be beneficial in decreasing the absorption and subsequent negative effect on performance of this mycotoxin since it is lipid soluble. However, it is important to have some lipid in the diet since feeding a fat-free diet has been shown to depress the activity of certain liver enzyme systems that are responsible for detoxification of toxic compounds such as mycotoxins. The mechanism involved usually involves converting non-polar toxicants (i.e., mycotoxins) into more polar compounds which are more easily excreted from the body. These enzyme systems, along with other vital systems should not ever be limited from functioning at their full potential due to a lack of nutrients. It is believed, by researchers that this is why high quality, highly digestible protein sources such as fish meal have been shown to be beneficial in activating the protective enzyme systems that detoxify mycotoxins and help remove them from the body.
Using a vitamin/mineral stress package in the water and using specific antioxidants such as vitamins A, E, C is very beneficial during aflatoxicosis since AFB-1 induces oxidative stress in liver and other vital organs. Vitamin C is especially important in helping to maintaining the immune system. Selenium is also an essential part of antioxidant systems in the body and supplementing it to the diet at the highest legal amount permitted in the U.S. (i.e., 0.3 ppm) is beneficial. Fusarium mold interferes with the utilization of copper and thiamine. Supplementing 100 ppm Cu and 5 to 10 ppm thiamine during fusarium toxicosis has been shown to be beneficial and 200 ppm Cu has been reported to decrease the incidence of tibial dsychondroplasia caused by another Fusarium mycotoxin known as “fusarochromanone “. Supplementing the diets with 100 and 200 ppm Cu has also been shown to beneficial when less than 1 ppm AFB-1 is present.
All of the nutritional recommendations mentioned above were taken from various reports in the scientific literature during the past 50 years that have been shown to be beneficial to poultry and other animals in minimizing the damage that molds and mycotoxins have on their performance and survivability.
The information presented in this issue of Milwhite’s Journal was compiled by Dr. Orlando Osuna, Director of Health Services at Milwhite, Inc. and Dr. Richard Miles, Professor Emeritus, University of Florida, Gainesville, FL, USA.
Chen X., K. Naehrer, and T.J. Applegate. 2016. Interactive effects of dietary protein concentration and aflatoxin B-1 on performance, nutrient digestibility, and gut health in broiler chicks. Poultry Sci. 95: 1312-1315