ISSUE FOCUS 58 FEED & ADDITIVE MAGAZINE May 2024 “In the animal nutrition industry, various chelated Zn sources have been marketed for their claimed superior bioavailability over traditional sulfates. However, it is crucial to highlight that EFSA's opinions have not definitively concluded on this matter. To date, EFSA's scientific evaluations consistently challenge these claims of higher bioavailability for chelated Zn sources compared to standard sulfates.” STABILITY OF TRACE MINERALS: DOES THE SOURCE MATTER? Dr. Yron Joseph Y. Manaig R&D Animine Marion Taris R&D Animine Nutrients such as carbohydrates, fats, proteins, including minerals and vitamins, are primarily absorbed within the intestine. Before reaching this organ, the ingested bolus has to pass through an acidic environment: the stomach. The gastric milieu plays a crucial role in the digestion process across animal species, facilitating the activation of enzymes and the pre-digestion of proteins and lipids. TRACE MINERALS AND THE ACIDIC GASTRIC ENVIRONMENT As the feed enters the digestive system, pepsinogen and hydrochloric acid will be secreted to assist in the breakdown of feed and facilitate digestion. Across swine, poultry and ruminant species, the pH conditions in the gastric chyme usually range between 2.0 to 5.0 (Figure 1), before it reaches the small intestine. The acidic environment aids in the mineral solubilization for their absorption in the intestinal tract (Broom et al., 2021). Among the trace mineral sources in the market, we can find sulfates, oxides, chlorides, chelates, among others. In this article, we are going to focus on positively charged metals (cations). Regardless of the source, the first stage of trace mineral absorption is the exposure to the acidic environment of the stomach, where gastric juices and low pH promote the solubilization of trace minerals. During this stage, the physical-chemical properties of trace mineral sources play an important role: sources with large particles which are not completely soluble in mild acidic conditions, such as low-quality metal oxides, are
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