{"id":4031,"date":"2026-03-23T20:09:21","date_gmt":"2026-03-23T19:09:21","guid":{"rendered":"https:\/\/kigen.nl\/knowledge\/rg-92\/"},"modified":"2026-06-19T14:44:31","modified_gmt":"2026-06-19T12:44:31","slug":"rg-92","status":"publish","type":"page","link":"https:\/\/kigen.nl\/en\/knowledge\/rg-92\/","title":{"rendered":"RG-92"},"content":{"rendered":"

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RG-92<\/span><\/span><\/h1>
RG-92 is the additive that KiGen uses in the Marujyu Special food<\/div><\/header>
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What is RG-92?<\/span><\/span><\/h2>
To provide the most honest picture possible of the RG-92 product, we have gathered as much information as possible and described it below.<\/div><\/header>
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RG92 in the context of the koi hobby<\/p>\n

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  • RG92 is described by the producer (SARABiO \u6e29\u6cc9\u5fae\u751f\u7269\u7814\u7a76\u6240<\/span> in Beppu) as a natural extract derived from a unique micro-alga (green alga) that lives in hot springs.<\/li>\n
  • It is therefore not a “classic” chemical additive, but a hot-spring algae extract that is also positioned as a feed ingredient in livestock farming and aquaculture.<\/li>\n
  • SARABiO also mentions (on their own site) that in 2021 it was classified as feed\/\u98fc\u6599<\/span><\/li>\n<\/ul>\n

    Application in aquaculture (what is the objective)?<\/b><\/p>\n

    On the same page, SARABiO mentions that trials have been conducted in aquatic animals\/aquaculture (including with hirame \/ flounder) and that these trials showed, among other things:<\/p>\n

      \n
    • Faster growth (\u5897\u4f53\u4fc3\u9032<\/span>)<\/li>\n
    • Lower mortality (\u3078\u3044\u6b7b\u6291\u5236<\/span>)<\/li>\n
    • Better FCR \/ feed efficiency (\u5897\u8089\u4fc2\u6570\u6539\u5584<\/span>)<\/li>\n<\/ul>\n

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      RG-92<\/span><\/span><\/h3>
      How does RG92 get \"into the fish\"?<\/div><\/header>
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      <\/p>\n

      According to SARABiO’s FAQ, the standard administration is:<\/p>\n

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      • By mixing it with the food.<\/li>\n
      • They also explicitly mention that it can (alternatively or additionally) be mixed with water and that it can be mixed with regular compound feed or drinking\/breeding water.<\/li>\n<\/ul>\n

        Practical use in the farm\/koi pond (what does that usually mean)?<\/b><\/p>\n

        In aquaculture, this almost always comes down to one of these routes in practice:<\/p>\n

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        1. Adding it into pellets (in the feed factory as a premix\/ingredient in the recipe), or<\/li>\n
        2. Top-dressing \/ coating on-site (mixing\/coating extract over existing pellets just before feeding), or<\/li>\n
        3. Via water administration (if the product is intended\/stable for that; they suggest “water etc.” as an option).<\/li>\n<\/ol>\n

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          RG-92<\/span><\/span><\/h3><\/header>
          <\/p>\n

          In close consultation with the producer of RG-92, KiGen has consciously chosen to mix RG-92 directly into the food. Thanks to its excellent heat resistance\u2014the algae from which RG-92 is extracted originate from hot springs\u2014this ingredient is ideally suited for application during the extrusion process. <\/p>\n

          The result of this choice is clear and consistent: RG-92 is present as a full ingredient in every single food pellet. This ensures even intake and maximum effectiveness with every feeding. <\/p>\n

          And from a biological perspective?<\/b><\/p>\n

          When mixed with food, RG92 enters via oral intake into:<\/p>\n

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          • The gastrointestinal tract (where effects on gut health\/inflammation\/energy metabolism are claimed), and then<\/li>\n
          • (Depending on the active fractions) absorption through the gut to the rest of the body.<\/li>\n<\/ul>\n

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            RG-92 Flowchart<\/span><\/span><\/h3><\/header>
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            Intake of RG-92 via food
            \u2193
            <\/span>Release in the gastrointestinal tract
            \u2193
            <\/span>Support of gut function & intestinal barrier
            \u2193
            <\/span>Improved nutrient absorption (protein \/ fat \/ energy)
            \u2193
            <\/span>Absorption of bioactive fractions via the gut
            \u2193
            <\/span>More efficient energy metabolism at the cellular level
            \u2193
            <\/span>Healthy growth + increased vitality + better resistance<\/p>\n

            RG-92 and heat: what does 90 \u00b0C during extrusion mean?<\/b><\/p>\n

            The answer to this question is obviously very important.<\/p>\n

            In the section on pro- and prebiotics, KiGen argues that living organisms largely or entirely die off during extrusion. KiGen does not want to market koi food that doesn’t do what we promise. <\/p>\n

            RG-92 is (according to the Japanese producer SARABiO) an extract of thermophilic micro-algae from hot springs (onsen) in Beppu. That is a major advantage here: <\/p>\n

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            • The origin is an organism that naturally lives at elevated temperatures<\/li>\n
            • The active fractions are described as more heat- and pH-stable than many classic vitamins, enzymes, or probiotics<\/li>\n<\/ul>\n

              This makes RG-92 more suitable for extrusion than, for example, live bacteria or sensitive enzymes.<\/p>\n

              90 \u00b0C: a problem or not?<\/b><\/p>\n

              In feed technology, the rule of thumb is:<\/p>\n

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              • 90 \u00b0C \u2013 briefly \u2192<\/span> usually acceptable for:\n
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                • Algae extracts<\/li>\n
                • Polysaccharides<\/li>\n
                • Certain lipid fractions<\/li>\n
                • Non-living bioactive components<\/li>\n<\/ul>\n<\/li>\n
                • >120 \u00b0C or long residence time \u2192<\/span> often results in degradation<\/li>\n
                • KiGen food is heated to 90\u00b0C for 3 minutes<\/li>\n<\/ul>\n

                  Does RG-92 remain biologically “active” after extrusion?<\/b><\/p>\n

                  Important distinction:<\/p>\n

                  RG-92 is not a probiotic (no living cells), so it doesn’t need to survive, it just needs to not break down chemically.<\/p>\n

                  Probable mechanism of action (based on what SARABiO claims + comparable products):<\/p>\n

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                  • Metabolic modulation<\/li>\n
                  • Gut health \/ anti-inflammatory effects<\/li>\n
                  • Improved nutrient utilization (FCR)<\/li>\n
                  • Possible effect on mitochondrial activity (this is often mentioned for RG-92 in livestock farming)<\/li>\n<\/ul>\n

                    These are effects that:<\/p>\n

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                    • Are not dependent on living structures<\/li>\n
                    • Are dependent on the structural integrity of extract components<\/li>\n<\/ul>\n

                      Extrusion at 90 \u00b0C is therefore perfectly compatible with its function.<\/p>\n

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