According to the FAO’s SOFIA report 2024, global aquaculture production in 2022 reached an unprecedented 223.2 million tonnes and for the first time in history, raised fish officially surpassed wild-caught fish. This is a significant point in history. However, there also exists a growing crisis that will be caused by the run-on effects of disease outbreaks, overuse of antibiotics and stress in fish resulting in slower growth rates than expected.
Aquaculture producers, researchers and policy makers are now looking to what has existed for much longer than any pharmaceutical products, nature itself. Peer-reviewed studies published during 2024 – 2025 have been supporting what a number of veteran aquaculture professionals have been thinking for some time. The correct natural additives do not only replace antibiotics, but many times they outperform antibiotic treatments.
Let’s talk about Phytogenics.
Phytogenic feed additives (PFAs), which include compounds extracted from plants such as herbs and spices, have recently been receiving considerable attention in aquaculture. A recent research conducted on Nile tilapia involving the use of phytogenic mixtures encapsulated within a matrix indicated that the inclusion of PFAs resulted in an increase in the final body weight, specific growth rates (SGRs), and tank biomass of fish. At the same time, there was a reduction in the feed conversion ratio (FCRs) of the fish by about 8%-9%. Alongside these advantages, it was observed that PFAs increased the survival rates of fish against the bacterium Streptococcus agalactiae, which causes massive deaths among tilapia.
How do PFAs enhance feed ingestion?
PFAs contain bioactive compounds such as flavonoids, essential oils, and saponins, which stimulate digestive enzyme activity, decrease gut inflammation, and modulate immune responses. A recent review article published in Aquaculture International suggested that phyto-nutrients support the structural integrity of mucosal membranes and promote cytokine activity, thereby keeping the immune function of the fish at a low grade of readiness (a “readiness state”) so that it can mount an immediate response to infections.
Probiotics & Prebiotics
Just like your gut health, the fish gut is about maintaining microbiome diversity so it stays healthy. Probiotics play a role by adding beneficial bacteria, while prebiotics (such as inulin and fructo-oligosaccharides) help feed those bacteria and encourage their growth.
And we are seeing the impact of this strategy grow. In one study of hybrid sturgeon conducted in 2025, adding Bacillus subtilis as a supplement improved both growth and disease resistance against Aeromonas hydrophila (one of the most prevalent bacterial pathogens in freshwater aquaculture). In addition, during studies of Mystus cavasius, using synbiotics (a blend of prebiotics and probiotics) significantly reduced fish mortality after infection by Aeromonas hydrophila compared to control groups receiving no prebiotics/probiotics.
According to a review published in Fishes MDPI in 2025, the addition of probiotics to fish intestines directly enhances T-lymphocyte activity and phagocyte response, both of which are critical components of immune function in fish. When the microbiota of the gut has a proper balance, it acts as both an engine of growth and a fortress against disease.
Natural Antioxidants Fights Oxidative Stress
A factor that is often overlooked by many fish producers, is that oxidative stress may be secretly diminishing their production levels. Stressed fishes experience high levels of reactive oxygen species (ROS), which damage DNA, lipids and proteins, and are produced when fish are subjected to high-density stocking, poor-quality water, fluctuating temperatures, and/or exposure to ammonia. The result of this oxidative stress can be slower growth, weakened immune systems, lower fillet quality, and increased susceptibility to disease.
In January 2025, an article published in the journal Biology (MDPI) discussed how naturally-occurring antioxidants like carotenoids, polyphenols, vitamins C and E, flavonoids, and polysaccharides, can neutralize ROS and help activate the Nrf2/ARE gene expression pathway. This activation signals the fish to turn on its own internal antioxidant defence system. Therefore, these natural antioxidants are more than just dietary supplements; they act as “switches” to turn on the fish’s antioxidant defence system.
A good example of a natural antioxidant is astaxanthin (a carotenoid found in crustaceans and algae). Astaxanthin not only provides colour enhancement but also an immune boosting function, making it a great option for producers focused on premium-quality fish and seafood products.
Beta-Glucans & Nucleotides
Beta-glucans are among the most investigated naturally occurring immunostimulants in aquaculture research. These naturally occurring immunostimulants are found in the cell wall of yeast and certain fungi, which interact with specific cell receptors present on immune cells’ surface and lead to a chain of activities that improve non-specific and specific immune responses.
Nucleotides are the basic units of DNA and RNA and are classified as semi-essential during times of rapid growth. Research on red sea bream has shown that feeding diets containing nucleotides results in improved growth performance, immune response, and oxidative stress resistance. Juvenile fish require high nucleotides due to the increased number of cell divisions. Hence, adding nucleotides to their feed is physiologically beneficial.
In a review article published in Fish & Fishes (MDPI) in 2025, nucleotides are listed together with phytogenics and probiotics as the top three categories of compounds driving the natural additive trend in finfish and shrimp aquaculture.
Fish that eat smarter, grow faster and fall sick less often.
Presently, the aquaculture sector is experiencing rapid change due to increased consumer scrutiny, a growing demand for antibiotic-free methods of production, and stricter government regulations regarding environmental impacts. There is no longer any doubt that this transition will be successful because the available scientific data can support it not at the expense of previous modes of operation, but rather as an actual leap forward in technology.
Unfortunately, there is no ‘one-size-fits-all’ solution to aquaculture nutrition. Things such as dosage, mixture, specificity by the type of animal, and how the ingredient is delivered (microencapsulation has been demonstrated to play a vital role in helping preserve the bioactivity of the nutritional ingredients through their incorporation into the diet) will have a tremendous effect on the success of these products. Therefore, fish that eat smarter, grow faster and fall sick less often.
Frequently Asked Questions
Q1. Are natural feed additives as effective as antibiotics for preventing disease in farmed fish?
There is no doubt that there are numerous studies confirming that natural products, especially phytochemicals, probiotics, and beta-glucans, strengthen immunity and prevent infections. However, when it comes to treating existing bacterial infections, antibiotic use can be justified in clinical settings. What really makes natural feed supplements effective is their capacity to minimize the necessity for such interventions.
Q2. Can these additives be used across all fish species, or are they species-specific?
Numerous experiments have been conducted involving such fish species as tilapia, salmon, sea bass, shrimps, sturgeon, among others. Usually, the outcome is positive; however, the required dosage, and additives may differ depending on the fish species. For instance, beta-glucan application in Nile tilapia in tropical environment can be quite effective, whereas in Atlantic salmon in RAS might fail to bring expected results.
Q3. Do natural feed additives affect the taste or quality of fish for consumers?
Generally positively. Antioxidants such as astaxanthin contribute to the improvement of the flesh coloring and prevent lipid oxidation. A few researches have proven that fish fed on natural additives-containing diet have the same or even better quality fillets than those reared traditionally.
Q4. How are these additives delivered to fish? Are they just mixed into the feed?
Yes, most of the additives are included in the pellets produced by the manufacturer. But there is a specific thing here that phytogenic additives may decompose at high temperatures in the extrusion process. Therefore, microencapsulation plays a crucial role here.
Q5. Are natural feed additives approved and regulated worldwide?
The regulatory framework differs across nations and geographical regions. The European Union, United States, and several Asian countries regulate the approval of feed additives. However, there is no universal regulation system in place for natural feed additives yet. In a Fishes journal article from 2025, it was recommended that better international harmonization be established with an increase in implementation.
