Nutritional and functional properties of mixed brown seaweeds and the growth performance of goldfish fed a pellet diet formulated with seaweeds

The nutrient profile and pharmaceutical activities were analyzed for seaweeds (Ascophyllum nodosum, Sargassum polycystum, Sargassum cristaefolium, Hormophysa cuneiformis, and Hormophysa triquetra) in the fish diet. The total protein content was greatest (8.4±0.2%) in S. polycystum, and the highest lipid content was detected in S. cristaefolium (3.7±0.1%). The crude fiber content was greatest (13.8±0.7%) in S. polycystum, and the carbohydrate content was high (35.2±0.5%) in S. polycystum. The phenol (73.1±1.1 mg GAE/g DW) and flavonoid (85.2±1.1 mg CE/g DW) contents were high in S. polycystum, whereas the tannin content was high in S. cristaefolium (15.5±0.8 mg GAE/g DW). Sargassum polycystum presented the maximum DPPH activity (64.4±2.2%) and H2O2 activity (45.8±1.3%). Equal amounts of seaweed (A. nodosum, S. polycystum, S. cristaefolium, H. cuneiformis, and H. triquetra) were mixed and used for feed formulation. The experimental diet was prepared by mixing 5% to 10% seaweed with other feed ingredients. The experimental diet was prepared with soybean oil, fish oil, and water. Compared with the control diet, the seaweed-supplemented diet improved fish growth (p<0.05). Overall, the results revealed the beneficial effects of seaweed on the feed of goldfish.