ISSUE FOCUS 24 FEED & ADDITIVE MAGAZINE November 2022 In animal feed, fat and oil are important sources of energy. They have to be absorbed and metabolized to be efficiently used by the host, driving the energy to body weight gain. As fat sources represent an important cost in formulation, some feed additives were developed to enhance fat digestion and improves performance. Monovalent copper is one of them with a specific mode of action now well described. 1. ABSORPTION OF LIPIDS IN MONOGASTRIC The first and limiting step of lipid absorption is the emulsification process, which happens thanks to the bile salts action. They coat the fatty acid, decreasing the size of fat globule and providing more surface area for lipase action. Thanks to their action, the lipase can transform the fat globule into micelles which can be easily absorbed in the intestine. Bile acids (BA) are synthesized from cholesterol in the liver (primary BA), conjugated to glycine or taurine (conjugated BA) and stored in the gallbladder to be released in the intestine. In their conjugated form, they are efficient emulsifiers improving lipid digestion. However, they can be deconjugated by the gut microbiota via the enzyme bile salt hydrolase (BSH), and also be converted into secondary BA by the 7α-dehydroxylation. These enzymatic reactions done by the microbiota are not profitable for the animal metabolism: deconjugated BA are not efficient to emulsify fat; secondary BA can be toxic to the body if in high concentrations. The ideMICROFLORA MODULATION BY MONOVALENT COPPER & FAT DIGESTIBILITY, A RELATION? “High dietary levels of copper (Cu) are being used since long time to promote the growth of monogastric animals. There are no doubts about the efficacy of Cu in promoting growth, but its mode of action is still under debate. One of possible mechanisms is the inhibition of bile salt hydrolase (BSH) activity, which has an effect on the dietary utilization and metabolism of lipid.” Axel Minetto Product Manager Animine Alessandra Monteiro R&D Manager Animine
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