Dietary Azolla meal enhances growth, immune status, and liver health in thin-lip grey mullet (Liza ramada) fingerlings: a sustainable approach to Aquafeed optimization

This study assessed the nutritional, immunological, and hepatic impacts of dietary Azolla meal (Azolla pinnata) as a sustainable alternative to conventional plant-based feed ingredients in Liza ramada (thin-lip grey mullet) aquaculture. Fingerlings were fed isonitrogenous and isocaloric diets where Azolla meal progressively replaced soybean meal and yellow corn at inclusion levels of 0%, 5%, 10%, 15%, and 20% over a 10-week period. Results revealed that the 10% inclusion level optimally enhanced growth performance (final body weight, weight gain), feed conversion ratio (1.78), and protein efficiency ratio. Hematological analysis revealed significant improvements in red blood cell count, hemoglobin concentration, and hematocrit levels, indicating enhanced systemic oxygen transport and improved metabolic status. Additionally, fish in the 10% Azolla group exhibited superior liver function, characterized by reduced ALT, AST, and urea levels, as well as enhanced albumin and globulin profiles. Immune markers, including lysozyme and IgM were markedly elevated, alongside improved antioxidant enzyme activities. Digestive enzyme analysis revealed improved protease and amylase activity, particularly at the 10% level. However, a 20% inclusion induced signs of metabolic stress, suggesting a threshold beyond which Azolla may be detrimental. This study conclusively demonstrates that a 10% dietary inclusion of Azolla meal is optimal for enhancing growth, immunity, and hepatic health in thin-lip grey mullet, providing a viable strategy for sustainable Aquafeed formulation. Thereby supporting cost-effective and eco-friendly aquaculture practices.