ISSUE FOCUS FEED & ADDITIVE MAGAZINE March 2024 27 tamination hot spots can be found in North America and in parts of Europe and Asia. Extreme weather events such as drought and flooding, as well as changing weather patterns, can lead to substantial changes in mycotoxin distribution, frequency and spread. In a hanging climate, mycotoxins have the potential to contaminate new geographical areas and crops. INDIVIDUAL FEED INGREDIENTS Maize, millet, wheat, sorghum, soybeans, peanuts, and by-products created from contaminated core ingredients are the most sensitive crops to mycotoxins. In poultry diets, corn and its by-products tend to contribute the most risk, while small grains tend to be lower-risk ingredients. However, when we look at the individual ingredients from the 700 poultry samples, we can see that low-risk does not mean no risk. While on average wheat and soybeans have a low number of mycotoxins per sample, there were as many as 15 (soybean) and 18 (wheat) different mycotoxins detected in individual samples. THE EFFECTS OF MYCOTOXINS IN BROILER-BREEDERS Mycotoxins can cause damage to organs and have a negative impact on reproduction, gut health and immunity, directly affecting breeder performance, hatchability and therefore profitability. Once in the body, mycotoxins distribute through different pathways. They can accumulate in fat tissues, leading to penetration of the blood-brain barrier and the placental barrier. The half-life elimination time, or the time required to reduce the initial plasma concentration of the toxin, can be very long in the case of chronic exposure. DAMAGE TO ORGANS The gastrointestinal tract of the bird is the first organ to encounter mycotoxin contamination in the feed. Aflatoxins, type A trichothecenes (for example, T-2 toxins), type B trichothecenes (for example, deoxynivalenol, or DON), fumonisins, ochratoxins and ergot toxins all damage the gastrointestinal tract in various ways, causing problems such as mouth lesions, compromised intestinal integrity, reduced feed intake, reduced nutrient absorption, immunosuppression and wet litter. REPRODUCTION In breeders, these toxins can impact sexual maturity and can decrease egg production, egg quality and immune protection in day-old chicks. Poor fertility in both males and females is a common symptom of mycotoxin contamination. In males, mycotoxins such as diacetoxyscirpenol (DAS) can reduce reproductive organ weights and cause degenerative processes of the testes, which leads to reduced spermatozoa quality and an overall diminished semen quality. GUT HEALTH Ochratoxin contamination can lead to a variety of issues, including intestinal inflammation, diarrhoea, intestinal fragility and, in some cases, feed refusal. A classic sign of ochratoxin toxicity is kidney damage marked with increased levels of uric acid. Fusarium mycotoxins such as trichothecenes, fumonisins and zearalenone can all harm the gastrointestinal tract. The trichothecene group contains mycotoxins like DON and T-2/HT-2 toxins. Studies have demonstrated how the presence of T-2 toxins can lead to mouth lesions, growth depression, reduced feed consumption and decreased egg production. Although DON has been found to decrease nutrient uptake and intestinal cell integrity, its presence can actually increase the nutrients available for certain bacterial growth (for example, Clostridium perfringens, which causes necrotic enteritis). It also increases gut permeability, allowing nutrients to leak outside of the intestines. IMMUNITY AND VACCINE FAILURE Mycotoxins, even at lower levels, can impact the innate and acquired immune responses in birds, which in turn decreases the response to vaccines. Although mycotoxins’ effects on rapidly differentiating and proliferating cells are complex, the common mechanism for immunosuppression is through inhibiting protein synthesis. As a result, signals for the synthesis of antibodies and immunoglobulins are downregulated. Studies looking at vaccine response in the face of a mycotoxin challenge have consistently reported a reduction in titers, decreased white blood cell counts, reduced immunoglobulin levels and low immune organ weights. Contamination of
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