Microalgae additives may help seabream handle plant-based diets

Juvenile gilthead seabream fed a plant protein-heavy diet showed weaker growth and signs of impaired gut function, but adding low levels of microalgae-based nutraceuticals helped offset some of those effects, according to recent research in Animals and related follow-up work from the same research group. In a 90-day trial, fish on a low-fishmeal, low-fish-oil diet performed worse than fish on a more conventional control diet, while supplementation with the microalgae-derived additive LB-IMMUNOboost partly restored growth, metabolic measures, stress markers, and intestinal barrier function. A companion intestinal-function study also reported higher digestive enzyme activity and improved nutrient absorption markers with low dietary inclusion of related microalgae-based ingredients. (sciencedirect.com)

Why it matters: For veterinary professionals working in aquaculture, the findings add to the evidence that functional feed additives may help reduce the physiological tradeoffs that come with replacing marine ingredients with plant proteins. That matters because plant-based formulations can introduce anti-nutritional factors and are associated with altered digestive function, intestinal physiology, and chronic nutritional stress in carnivorous fish species. The practical takeaway is not that microalgae “solve” plant-based diets, but that targeted additives may help support gut integrity, feed efficiency, and fish welfare as producers push for more sustainable formulations. (rodin.uca.es)

What to watch: Expect more work on dose, cost-effectiveness, and whether these gut and stress-response benefits hold up at commercial scale and across other species. (sciencedirect.com)