Role of β-glucan on finfish and shellfish health and well-being: A systematic review and meta-analysis

This study aimed to conduct a systematic review and meta-analysis evaluating the inclusion of β-glucan in aquaculture animal diets and its impact on their health outcomes. Relevant studies were identified from Scopus and Web of Science databases. A total of 82 primary studies published between 1996 and 2024 were reviewed, of which 70 were included in the meta-analysis. The results revealed that the application of β-glucan to aquaculture animal's diets significantly enhanced specific growth rate (SGR; mean effect, g = 2.71; p < 0.001), feed conversion ratio (FCR; g = −3.88; p < 0.0001) and lowered mortality after exposure to pathogens. Likewise, β-glucan had a positive influence (p < 0.0001) on innate immune parameters (lysozyme and phagocyte activity, NBT, ACH50, and IgM). The study found that the effects of β-glucans varied among marine and freshwater fish where freshwater fishes (g = 2.05–6.57) exhibit better performance. This study also found a negative correlation between fish's innate immune response and trophic level, suggesting that fish with higher trophic levels may be less efficient at absorbing this bio-stimulant. Even though there were high heterogeneity (I² = 73%–97%, p < 0.05) due to the diversity of tested organisms and publication bias, our model and findings are valid. The findings suggest that the dietary application of β-glucans can have beneficial effects on growth and immune responses especially for freshwater species. The validity of these observations needs to be confirmed by further prospective studies.