Review maps smarter nutrition strategies for low-fishmeal aquafeeds
Bottom line
Version 1 — Brief
A new systematic review in Veterinary Sciences argues that formulating low-fishmeal aquafeeds takes more than simply correcting lysine and methionine. Using a PRISMA 2020-based approach, the authors synthesized peer-reviewed feeding trials on low-fishmeal, fishmeal-free, and high-alternative-protein diets, and found that other nutritional levers, including taurine, histidine, enzymes such as phytase and protease, fermentation, and other functional additives, often shape whether fish maintain growth, feed efficiency, and health when fishmeal is reduced. That matters because fishmeal brings more than protein: it also contributes palatability, digestibility, minerals, and bioactive compounds that can be hard to replicate with plant, animal by-product, insect, algal, or single-cell alternatives. (pubmed.ncbi.nlm.nih.gov)
Why it matters: For veterinary and aquaculture professionals, the review reinforces a practical point: low-fishmeal formulation is increasingly a whole-diet balancing exercise, not a two-amino-acid fix. Prior literature shows taurine can improve performance in some high-plant diets, histidine may become limiting in certain species such as tilapia, and phytase or fermentation can improve nutrient availability and help offset anti-nutritional factors in plant-heavy rations. In other words, feed changes aimed at sustainability or cost control can ripple into fish health, welfare, and production outcomes if the broader nutrient matrix is overlooked. (pubmed.ncbi.nlm.nih.gov)
What to watch: Expect follow-up work to focus on species-specific, additive-specific formulations that define which combinations best preserve health and performance as fishmeal inclusion keeps falling. (doi.org)
Version 2 — Full analysis
A new review in Veterinary Sciences adds nuance to one of aquaculture nutrition’s biggest questions: what does it really take to make low-fishmeal diets work? The authors conclude that balancing lysine and methionine alone often isn’t enough when fishmeal is heavily reduced or removed. Instead, successful formulations frequently depend on a broader package of amino acids, enzymes, processing strategies, and functional additives that help restore the nutritional and physiological roles fishmeal used to provide. (pubmed.ncbi.nlm.nih.gov)
That conclusion lands at a time when the industry is under growing pressure to reduce reliance on marine ingredients. Fishmeal remains nutritionally valuable because of its digestibility, amino acid profile, palatability, mineral content, and bioactive compounds, but supply is finite and pricing can be volatile. Recent industry reporting has highlighted tightening fishmeal availability, while newer reviews continue to frame fishmeal replacement as central to aquaculture’s sustainability and growth strategy. (seafoodsource.com)
Against that backdrop, the review’s main contribution is its emphasis on “nutritional balancing strategies” beyond the usual methionine-and-lysine correction. The broader literature supports that framing. Taurine supplementation has improved growth and product quality in some high-plant or low-fishmeal diets, including European seabass and pompano. Histidine can also become limiting in plant-based formulations for some species, and feed enzymes such as phytase and protease are widely studied for improving nutrient digestibility and phosphorus or protein utilization in alternative-protein diets. Fermentation is another recurring strategy because it can improve palatability and reduce anti-nutritional factors in plant ingredients. (pubmed.ncbi.nlm.nih.gov)
The paper also fits with a wider shift in the science from asking whether fishmeal can be replaced to asking how replacement can be made biologically reliable. Reviews published in the past two years have pointed to persistent gaps around health, welfare, digestibility, anti-nutritional factors, and species-specific limits for alternative proteins. Newer work on single-cell proteins, microalgae, insect meals, and poultry by-product meal suggests that alternatives can perform well, but usually not as drop-in substitutes across all species and production settings. (pubmed.ncbi.nlm.nih.gov)
Industry commentary is moving in the same direction. SeafoodSource recently reported that fishmeal and fish oil remain difficult to replicate fully, especially for functions tied to omega-3s, highly digestible marine proteins, and fish health, even as the sector pushes novel ingredients toward scale. That doesn’t contradict the review’s message so much as sharpen it: replacement is possible, but only with more precise nutritional engineering than early substitution efforts sometimes assumed. (seafoodsource.com)
Why it matters: For veterinarians, fish health specialists, and aquaculture teams, this review is a reminder that feed reformulation is also a health management decision. Low-fishmeal diets can affect growth, gut function, mineral utilization, immune status, behavior, and fillet quality if deficiencies or digestibility problems go unaddressed. The practical takeaway is that ration evaluation should look past crude protein and the headline amino acids, especially when pet parents, retailers, or sustainability programs are pushing for lower marine ingredient use. Species, life stage, ingredient source, processing method, and additive package all matter. (pubmed.ncbi.nlm.nih.gov)
What to watch: The next phase is likely to be more targeted and more commercial: species-specific decision frameworks, better evidence on additive combinations, and more data linking low-fishmeal formulations to health and performance under farm conditions, not just controlled trials. As fishmeal supply pressure continues and alternative ingredients scale up, the winning diets will probably be the ones that treat fishmeal replacement as a full nutrient-function replacement problem, not a simple protein swap. (doi.org)
Common questions
Do low-fishmeal aquafeeds need more than lysine and methionine correction?
Yes. The review says successful low-fishmeal diets often need a broader package of amino acids, enzymes, processing strategies, and functional additives, not just lysine and methionine.What other ingredients or strategies did the review highlight?
Taurine, histidine, enzymes such as phytase and protease, fermentation, and other functional additives were all cited as important in some diets.Why is fishmeal hard to replace in aquafeeds?
Fishmeal provides more than protein. It also contributes palatability, digestibility, minerals, and bioactive compounds that can be difficult to match with alternative ingredients.What can happen if low-fishmeal diets are not balanced well?
The article says growth, feed efficiency, health, gut function, mineral utilization, immune status, behavior, and fillet quality can be affected if deficiencies or digestibility problems are not addressed.