Evaluation of <scp> <i>Sargassum ilicifolium</i> </scp> as a functional feed additive to improve growth, haematology and disease resistance in <scp> <i>Catla catla</i> </scp>

This experiment was conducted to evaluate the efficacy of brown seaweed (Sargassum ilicifolium) supplementation on growth performance, blood parameters and digestive enzyme activity in Catla catla for 60 days. Three hundred fingerlings were acclimatized for a week and then stocked into four experimental groups with triplicates (25 fish/aquarium), including T0: control group and three treatments supplemented with brown seaweed (T1: 3% BSW, T2: 5% BSW and T3: 7% BSW). Fingerlings were fed at 4% of their total body weight, provided twice a day. The results showed that T3 (7% BSW) treatment had the highest average body weight, average body length, protein efficiency ratio and specific growth rate. Haemoglobin levels, red blood cells and mean cell haemoglobin concentration (MCHC) were significantly (p < 0.05) higher in fish fed with diets 3% BSW (T1) compared to other dietary groups. In contrast, white blood cells, neutrophils and eosinophils were significantly (p < 0.05) higher in the T3 treatment. Furthermore, inclusion of 7% BSW into the fish diet improved the activity of digestive enzymes, such as amylase and protease, in the liver and gut. Findings also indicated a significantly higher survival rate observed in treatment groups challenged with Aeromonas hydrophila. In conclusion, 7% supplementation enhanced the growth and immunity of C. catla. The findings suggest that S. ilicifolium can serve as a promising herbal immunostimulant in aquaculture, offering a sustainable and eco-friendly approach to improve fish health and disease resistance.